| 1. |
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| 2. |
- Kennergren, Charles, 1948, et al.
(författare)
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A single-centre experience of over one thousand lead extractions.
- 2009
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Ingår i: Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology. - : Oxford University Press (OUP). - 1532-2092. ; 11:5, s. 612-7
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: The aim of the study was to present a single-centre experience of pacemaker and implantable cardioverter defibrillator (ICD) lead extraction using different methods, mainly laser-assisted extraction. METHODS AND RESULTS: Data from 1032 leads and 647 procedures were gathered. A step-by-step approach using different techniques while performing an ongoing risk-benefit analysis was used. The most common indications were local infection, systemic infection, non-functional lead, elective lead replacement, and J-wire fracture. Mean implantation time for all leads was 69 months and for laser-extracted leads 91 months. Laser technique was used to extract 60% of the leads, 29% were manually extracted, 6% extracted with mechanical tools, 4% were surgically removed, and 0.6% extracted by a femoral approach. Failure rate was 0.7%, and major complication rate was 0.9%. No extraction-related mortality occurred. Median time for laser extraction was 2 min. Long implantation time was not a risk factor for failure or for complication. CONCLUSION: Pacing and ICD leads can safely, successfully, and effectively be extracted. Leads can often be extracted by a superior transvenous approach; however, open-chest and femoral extractions are still required. Laser-assisted lead extraction proved to be a useful technique to extract leads that could not be removed by manual traction. The results indicate that the paradigm of abandoning redundant leads, instead of removing them, may have to be reconsidered.
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| 3. |
- Kennergren, Charles, 1948
(författare)
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Cardiac implantable electronic device treatment: taking care of complications.
- 2009
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Ingår i: Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology. - : Oxford University Press (OUP). - 1532-2092. ; 11:11, s. 1419-20
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Kennergren, Charles, 1948, et al.
(författare)
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Laser-assisted lead extraction: the European experience.
- 2007
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Ingår i: Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology. - : Oxford University Press (OUP). - 1099-5129. ; 9:8, s. 651-6
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: The aim of this study is to investigate the safety and effectiveness of Excimer laser-assisted lead extraction in Europe. The final European multi-centre study experience is presented. METHOD AND RESULTS: The Excimer is a cool cutting laser (50 degrees C) with a wavelength of 308 nm. The energy is emitted from the tip of a flexible sheath and is absorbed by proteins and lipids, 64% of the energy is absorbed at a tissue depth of 0.06 mm. The sheath is positioned over the lead, and the fibrosis surrounding the lead is vaporized while advancing the sheath without damaging other leads. From August 1996 to March 2001, 383 leads (170 atrial, 213 ventricular) in 292 patients (mean age 61.6 years, range 13-96) were extracted at 14 European centres. Mean implantation time was 74 months (3-358). Most frequent indications were pocket infection (26%), non-functional leads (21%), patient morbidity (21%), septicaemia or endocarditis (14%), erosion (5%), and lead interference (8%). Median extraction time was 15 min (1-300). Complete extraction was achieved in 90.9% of the leads and partial extraction in 3.4%. Extraction failed in 5.7% of the leads. Major complications = perforations caused 10/22 (3.4/5.7%) of the failures. Most partially extracted patients were considered clinically successful, as only minor lead parts without clinical significance were left. Femoral non-laser technique was used to remove 8/12 of the non-complication failures. The total complication rate, including five minor complications (1.7%), was 5.1%. No in-hospital mortality occurred. CONCLUSION: Pacing and implantable cardioverter-defibrillator leads can safely, effectively, and predictably be extracted. Open-heart extractions can be limited to special cases. The results indicate that the traditional policy of abandoning redundant leads, instead of removing them, may be obsolete in many patients.
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| 5. |
- Raak, Ragnhild, 1948-, et al.
(författare)
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Thermal thresholds and catastrophizing in individuals with chronic pain after whiplash injury
- 2006
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Ingår i: Biological Research for Nursing. - : SAGE Publications. - 1099-8004 .- 1552-4175. ; 8:2, s. 138-146
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Tidskriftsartikel (refereegranskat)abstract
- Thermal sensitivity, thermal pain thresholds, and catastrophizing were examined in individuals with whiplash associated disorders (WAD) and in healthy pain-free participants. Quantitative sensory testing (QST) was used to measure skin sensitivity to cold and warmth and cold and heat pain thresholds over both the thenar eminence and the trapezius muscle (TrM) in 17 participants with WAD (age 50.8± 11.3 years) and 18 healthy participants (age 44.8± 10.2 years). The Pain Catastrophizing Scale (PCS) was used to determine pain coping strategies, and visual analogue scales were used for self-assessment of current background pain in individuals in the WAD group as well as experienced pain intensity and unpleasantness after QST and sleep quality in all participants. There were significant differences in warmth threshold and cold and heat pain thresholds of the TrM site between the WAD and pain-free groups. Significant differences between the two groups were also found for the catastrophizing dimension of helplessness in the PCS and in self-assessed quality of sleep. A correlational analysis showed that current background pain is significantly correlated with both cold discrimination and cold pain threshold in the skin over the TrM in individuals with WAD. These findings imply that thermal sensitivity is an important factor to consider in providing nursing care to individuals with WAD. Because biopsychosocial factors also influence the experience of pain in individuals with WAD, the role of nurses includes not only the description of the pain phenomenon but also the identification of relieving and aggravating factors.
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| 6. |
- Salander, Pär, 1948-
(författare)
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Attributions of lung cancer : my own illness is hardly caused by smoking
- 2007
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Ingår i: Psycho-Oncology. - : Wiley. - 1057-9249 .- 1099-1611. ; 16:6, s. 587-592
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Tidskriftsartikel (refereegranskat)abstract
- People experiencing unexpected negative events tend to make sense of the situation through causal attributions. It seems that having some sort of answer to “why-me” makes the event less shattering and the world more controllable. We know for instance that the great majority of women with breast cancer tend to have clear ideas about its causes. Lung cancer, in contrast to breast cancer, has a well-known significant cause, as smoking explains about 80% of the incidence. This paper deals with the attribution process in lung cancer. It examines how lung cancer patients attribute the cause to their disease and how this relates to an understanding of how people deal with strain. Twenty-three patients with advanced non-small-cell lung cancer were consecutively followed by means of repeated interviews throughout the course of the disease. It emerged that among the smokers the most common attribution was “don’t know” – smoking was not seen as the prime cause to their cancer. This finding is discussed in relation to the few earlier somewhat contradictory studies that exist and it is argued that the finding is according well with the concept of ‘disavowal’ being the central process concerned in dealing with strain.
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| 7. |
- Salander, Pär, 1948-, et al.
(författare)
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Gender differences in patient´s written narratives when being diagnosed with cancer
- 2005
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Ingår i: Psycho-Oncology. - : John Wiley & Sons. - 1057-9249 .- 1099-1611. ; 14:8, s. 685-695
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Tidskriftsartikel (refereegranskat)abstract
- The medical field has shown a growing interest in gender and gender differences. In psychosocial oncology, for example, some studies suggest that men and women cope differently with cancer; e.g. women express their emotions more readily than men do, and men rely more on their healthy spouse.Using a qualitative perspective, this study examines 83 narratives written by male and female cancer patients who were asked to write down how they experienced receiving their cancer diagnosis. The narratives were analyzed both as to structure and content.The women wrote longer, more personally, and more emotionally than the men, and to a greater extent they included family members and other relatives in their stories. When the men mentioned relatives, they mainly referred to their spouse. Men and women commented differently as to their experiences of ‘reception’; i.e. how their psychological needs were addressed and ‘connection’; i.e. whether they felt in sufficient contact with medical staff. Although the women described good reception, they complained a lot about bad connection. Among the men, it was just as common to report about positive as negative experiences in both categories.There are reasons to be cautious when evaluating these findings. The found differences may be due to different ways of reacting to similar situations or different willingness and ways of commenting on similar situations, but also to different reception and connection for men and women. Further research should focus on the basic question: Are men and women without medical reasons being treated differently during their oncological treatment?
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| 8. |
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| 9. |
- Salander, Pär, 1948-
(författare)
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Who needs the concept of spirituality?
- 2006
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Ingår i: Psycho-Oncology. - 1057-9249 .- 1099-1611. ; 15:7, s. 647-9
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 10. |
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| 11. |
- Anderlund, Magnus F., et al.
(författare)
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Redox chemistry of a dimanganese(II,III) complex with an unsymmetric ligand : Water binding, deprotonation and accumulative light-induced oxidation
- 2006
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :24, s. 5033-5047
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Tidskriftsartikel (refereegranskat)abstract
- A dinuclear manganese complex {[(Mn2L)-L-II,IIII(mu-OAc)(2)]-ClO4} has been synthesised, where L is the dianion of 2-{[bis-(pyrid-2-ylmethyl)amino]methyl}-6-{[(3,5-di-tert-butyl-2- hydroxybenzyl)(pyrid-2-ylmethyl)amino]methyl)-4-methylphenol, an unsymmetric binucleating ligand with two coordinating phenol groups. The two manganese ions, with a Mn-Mn distance of 3.498 angstrom, are bridged by the two bidentate acetate ligands and the 4-methylphenolate group of the ligand, resulting in a N3O3 and N2O4 donor set of Mn-II and Mn-II, respectively. Electrochemically [Mn2(II,III)L(mu-OAc)(2)](+) is reduced to [(Mn2L)-L-II,II(mu-OAc)(2)] at E-1/2(1)=-0.53 V versus Fc(+/0) and oxidised to [(Mn2L)-L-III,III(mu-OAC)(2)](2+) at E-1/2(2)=0.38 V versus Fc(+/0). All three redox states have been characterised by EPR, IR and UV/Vis spectroscopy. Subsequent oxidation of [(Mn2L)-L-II,III(mu-OAc)(2)](2+) [E-1/2(3)=0.75 V vs. Fc(+/0)] in dry acetonitrile results in an unstable primary product with a lifetime of about 100 ins. At high scan rates quasireversible voltammetric behaviour is found for all three electrode processes, with particularly slow electron transfer for the II,III/II,II [k(o)(1) = 0.002 cms(-1) and III,III/II,III [k(o)(2) = 0.005 cms(-1)] couples, which can be rationalised in terms of major distortions of the Mn-II centres. In aqueous media the bridging acetates are replaced by water-derived ligands. Deprotonation of these stabilises higher valence states, and photo-induced oxidation of the manganese complex results in a (Mn2L)-L-IlI,IV complex with oxo or hydroxo bridging ligands, which is further oxidised to an EPR-silent product. These results demonstrate that a larger number of metal-centred oxidations can be compressed in a narrow potential range if build up of charge is avoided by charge-compensating reactions.
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| 12. |
- Andersson, Lena, et al.
(författare)
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Methodological aspects on measurement of Clara cell protein in urine as a biomarker for airway toxicity, compared with serum levels.
- 2007
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Ingår i: Journal of applied toxicology : JAT. - : Wiley. - 0260-437X .- 1099-1263. ; 27:1, s. 60-6
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Tidskriftsartikel (refereegranskat)abstract
- The Clara cell protein CC16, secreted from Clara cells in the lung, is discussed as a potential biomarker for toxic effects on the airways. An increased concentration of CC16 in serum may be caused by increased permeability of the lungs, caused by high levels of air pollution. Since CC16 is eliminated by renal excretion, it may be possible to use urine instead of serum samples. Few studies have been conducted on urinary CC16 (U-CC16), however.The aim was to investigate the optimal way of sampling and quantifying CC16 in urine samples and compare CC16 in human serum and urinary samples. Repeated sampling was performed in two groups of healthy subjects. First morning urine, 24 h urine, and matched blood and urine samples were collected.The excretion of U-CC16 increased over the day, e.g. from 0.08 microg h(-1) in the morning to 0.28 microg h(-1) in daytime and 0.16 microg h(-1) in the evening (medians in males). Morning samples (microg h(-1)) from males properly reflected the 24 h excretion (r = 0.91). The best correlation with 24 h excretion was obtained with creatinine-corrected first morning urine samples (r > 0.9). Generally, females had lower excretion of CC16 than males (medians 2.5 microg 24 h(-1) in females and 16 microg 24 h(-1) in males). There was significant intraindividual variation, but the interindividual variation was larger in both groups. There was an association between serum CC16 (S-CC16) and U-CC16 in morning samples. With optimal methods for sampling U-CC16, urine samples may be used in experimental studies of air pollution.
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| 13. |
- Bányai, István, et al.
(författare)
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On the Nature of VV Species in Hydrophilic Ionic Liquids: A Spectroscopic Approach
- 2008
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :34, s. 5373-81
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Tidskriftsartikel (refereegranskat)abstract
- Heteronuclear NMR experiments, in particular 51V, wereperformed with the aim to elucidate the nature of vanadates and peroxovanadates in hydrophilic ionic liquids (i.e., [bmim][BF4], [bmim][TfO] and [bdmim][BF4]). The data so far reported clearly indicate that ionic liquids have a strong influence on the solution chemistry of vanadate in water both for the formation of the aggregates (with and without H2O2) and for the rate of peroxide consumption catalyzed by vanadium. In BF4- containing ionic liquids, formation of vanadate-fluoride adducts is suggested. The obtained results are also discussed in the light of the reactivity data of peroxovanadates in ionic liquids.
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| 14. |
- Camenzind, Adrian, et al.
(författare)
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Nanostructure evolution : From aggregated to spherical SiO2 particles made in diffusion flames
- 2008
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :6, s. 911-918
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Tidskriftsartikel (refereegranskat)abstract
- The formation of nanostructured silica particles by oxidation of hexamethyldisiloxane (HMDSO) in co-annular diffusion flames is investigated by in-situ small-angle X-ray scattering (SAXS). This enabled the nonintrusive monitoring of the mass fractal dimension, the aggregate size, and the number of primary particles per aggregate, along with the silica volume fraction, the primary particle diameter, the geometric standard deviation, and the number density along the flame axis. Parallel to this, thermophoretic sampling (TS) of the particles and analysis by transmission electron microscopy (TEM) allowed for direct comparison of particle morphology to that obtained from the above SAXS analysis, which were compared also to the ultra-small-angle X-ray scattering (US-AXS) data for product particles collected from the filter. The flame temperature was measured by in-situ Fourier transform infrared (FTIR) spectroscopy. By increasing the oxygen flow rate, the laminar diffusion flame changed to a turbulent, premixed-like flame. Non-aggregated, spherical particles were formed in the former, while aggregates were formed in the latter flame. The relatively long high-temperature particle residence times in the laminar diffusion flame facilitated sintering of the aggregates formed earlier into compact spherical particles at later stages of the flame. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).
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| 15. |
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| 16. |
- Durieux, Guillaume, et al.
(författare)
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Rate and Mechanism of the Oxidative Addition of a Silylborane to Pt0 Complexes : Mechanism for the Pt-Catalyzed Silaboration of 1,3-Cyclohexadiene
- 2008
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Ingår i: European Journal of Inorganic Chemistry. - Weinheim : Wiley-VCH. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :27, s. 4236-4241
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Tidskriftsartikel (refereegranskat)abstract
- The chemical reduction of Pt(acac)(2) by DIBALH in the presence of phosphanes, which is used to generate active Pt-0 complexes in the Pt-catalyzed silaboration of cyclohexadiene by 2-(diinethylphenylsilyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1) leading to the 1,4-silaborated product, was mimicked by the electrochemical reduction of Pt(acac)(2) in the presence of 2 equiv. of PR3 (R = Ph, nBu). The electrochemical reduction generates free acac anions and neutral Pt-0-(PR3)(2) complexes. The kinetics of the oxidative addition of bromobenzene (used first as a model molecule) and silylborane 1 to the Pt-0 complexes was investigated and the rate constants determined. Pt-0(PnBu(3))(2) is much more reactive than Pt-0(PPh3)(2) towards 1. From the electrochemical study, it emerges that the acac anions released in the reduction of Pt(acac)(2) do not coordinate to the Pt-0(PR3)(2) complexes. Consequently, the rate of the oxidative addition of 1 to Pt-0(PR3)(2), generated either by the electrochemical reduction or by the chemical reduction by DIBALH, is not affected by the acac anions and a posteriori not by aluminum cations. The oxidative addition and the further step of the catalytic cycle [insertion of the diene into the Pt-B bond of the Si-Pt-B complex generated in the oxidative addition, with formation of the eta(3)-allyl)Pt-Si complex] were monitored by NMR spectroscopy. Pt-0 and Pt-II complexes involved in the catalytic cycle were characterized. The oxidative addition is faster when the ligand is PMe2Ph relative to that obtained with PPh3, in agreement with the electrochemical data. No reductive elimination within the ((eta(3)-allyl))Pt-Si complex is observed when the ligand is PMe2Ph, whereas reactions in the presence of PPh3 proceeded to give the final product. As a consequence, PPh3 is a better ligand than PMe2Ph for the catalytic reaction, as observed experimentally.
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| 17. |
- Forcato, M., et al.
(författare)
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Chiral, enantiopure aluminum(III) and titanium(IV) azatranes
- 2006
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :5, s. 1032-1040
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Tidskriftsartikel (refereegranskat)abstract
- Al-III and Ti-IV complexes of C-3-symmetric tetradentate trisamidoamme ligands with trigonal bipyramidal coordination geometry, containing chlorine or dialkylamido groups, or with a free coordination site in the apical position, have been synthesised by salt metathesis and amine elimination. Products with threefold symmetry were generally obtained for tetravalent titanium, whereas for the aluminium complexes either asymmetric structures with two of the three podand arms taking part in coordination to the metal or symmetric arrangements possessing the full threefold symmetry were formed depending on the steric properties of the ligands.
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| 18. |
- Gorlov, Mikhail, et al.
(författare)
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Mononuclear eta(6)-Arene Complexes of Lanthanides : One-Step Syntheses, Crystal Structures, and Arene Exchange
- 2008
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :33, s. 5191-5195
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Tidskriftsartikel (refereegranskat)abstract
- Gallium(III) halides react with cerium(III), ytterbium(III), or dysprosium(III) halides in the presence of alkylated benzenes yielding mononuclear complexes of the general formula [Ln(eta(6)-arene)(GaX4)(3)]. The X-ray structures of [Ce(C6H5Me)- (GaCl4)(3)] (1), [Ce(p-C6H4Me2)(GaCl4)(3)]center dot 0.5(p-C6H4Me2) (2), [Yb(C6H5Me)(GaCl4)(3)] (3), [Yb(p-C6H4Me2)(GaCl4)(3)]center dot 0.5(p- C6H4Me2) (4), and [Dy(C6H5Me)(GaBr4)(3)] (5) were determined. Arene ligands in the cerium-toluene compound 1 can be substituted by polycyclic aromatic hydrocarbons (PAHs); the compounds [Ce(naphthalene) (GaCl4)(3)] (6) and [Ce(pyrene)(GaCl4)(3)]center dot 0.5(pyrene) (7) have been isolated and structurally characterized.
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| 19. |
- Hopmann, Kathrin H., et al.
(författare)
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On the Role of Tyrosine as Catalytic Base in Nitrile Hydratase
- 2008
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :22, s. 3452-3459
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Tidskriftsartikel (refereegranskat)abstract
- Nitrile Hydratases (NHases) catalyze the conversion of nitriles to their corresponding amides. Two NHase classes exist, the Fe-III-NHases and the Co-III-NHases. Both harbour an intriguing active site, with a low-spin metal ion coordinated to deprotonated back-bone amides and oxidized cysteine residues. So far it has not been possible to conclusively determine the reaction mechanism of NHase. Here we employ density functional theory to investigate the recent proposal that a fully conserved second-shell tyrosine residue is the catalytic base of nitrile hydratase (J. Biol. Chem. 2007, 282, 7397-7404). In the proposed mechanism, the tyrosine is suggested to be in the tyrosinate state and to mediate nitrile hydration through activation of a water molecule, which attacks the metal-bound substrate. We have explored this mechanism employing quantum chemical active site models on the basis of the Co-III-NHase from P. thermophila JCM 3095 and the Fe-III-NHase from R. erythropolis N-771. Potential energy curves and optimized transition states are presented. The computed barriers for the two models are a few kcal/mol above the experimental value, indicating that the conserved second-shell tyrosine could function as the catalytic base of NHase. To further evaluate the likelihood of this mechanism, we estimated the pK(a) value of the second-shell tyrosine in each model. We also provide estimates of the energy involved in the exchange of a metal-bound water molecule with a nitrile substrate.
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| 20. |
- Hopmann, Kathrin H., et al.
(författare)
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Theoretical Investigation of the Second-Shell Mechanism of Nitrile Hydratase
- 2008
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :9, s. 1406-1412
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Tidskriftsartikel (refereegranskat)abstract
- Nitrile hydratases (NHases) are biocatalytically important enzymes that are utilized in the industrial production of acrylamide and nicotinamide. There are two different classes of NHases, harbouring either a low-spin Fe-III or a low-spin Co-III ion in the active site, in each case with the same peculiar set of ligands, involving deprotonated backbone amides and oxidized cysteine residues. The detailed reaction mechanism of NHase has not been established yet, but different proposals have been put forward. Depending on the binding site of the substrate, these can be divided into first-shell and second-shell mechanisms, respectively, Recently, we have investigated different first-shell mechanisms using quantum-chemical active-site models based on the iron-dependent NHase (Inorg. Chem. 2007, 46, 4850). Here we continue our investigation of the NHase reaction by exploring two different variations of the second-shell mechanism of the iron-dependent NHase. In the first, a metal-bound hydroxide ion performs a nucleophilic attack on the nitrile substrate, while in the second investigated mechanism, the oxidized cysteine, Cys114-SO-, acts as the nucleophile. We report energies, optimized transition state, and intermediate geometries for both investigated mechanisms. The calculated barriers are similar to the previously reported first-shell mechanism involving Cys114-SO- as catalytic base.
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| 21. |
- Höglund, Carina, 1981-, et al.
(författare)
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Sc3AlN : A New Perovskite
- 2008
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; 2008:8, s. 1193-1195
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Tidskriftsartikel (refereegranskat)abstract
- Sc3AlN with perovskite structure has been synthesized as the first ternary phase in the Sc–Al–N system. Magnetron sputter epitaxy at 650 °C was used to grow single-crystal, stoichiometric Sc3AlN(111) thin films onto MgO(111) substrates with ScN(111) seed layers as shown by elastic recoil detection analysis, X-ray diffraction, and transmission electron microscopy. The Sc3AlN phase has a lattice parameter of 4.40 Å, which is in good agreement with the theoretically predicted 4.42 Å. Comparisons of total formation energies show that Sc3AlN is thermodynamically stable with respect to all known binary compounds. Sc3AlN(111) films of 1.75 μm thickness exhibit a nanoindentation hardness of 14.2 GPa, an elastic modulus of 249 GPa, and a roomtemperature electrical resistivity of 41.2 μΩ cm.
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| 22. |
- Kurz, Philipp, et al.
(författare)
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Ligand variations in [ReX(diimine)(CO)(3)] complexes : Effects on photocatalytic CO2 reduction
- 2006
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :15, s. 2966-2974
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Tidskriftsartikel (refereegranskat)abstract
- Two series of complexes [MX(diimine)(CO)(3)] (M = Tc, Re) have been prepared, fully characterised and investigated for their ability to act as photocatalysts for the reduction of CO2 to CO. One series consists of complexes with different aromatic diimine ligands while keeping X = Br- constant. The second series describes complexes with diimine = 2,2-bipyridine and variations in the anionic ligand X-. Although numerous complexes of this type have been prepared and investigated before, a systematic study of their photocatalytic activity has not yet been carried out. Electrochemical and spectroscopic characterisation of these complexes has been performed with the objective of better understanding their respective activity in the photocatalytic CO2 reduction. Despite various modifications, catalytic activity is retained for all compounds exhibiting fluorescence, including [(TcCl)-Tc-99(bipy)(CO)(3)], whereas nonfluorescing compounds did not convert CO2 to CO. The correlation of catalytic activity and spectroscopic or electrochemical properties such as absorption or emission wavelengths, redox potentials or Stern-Volmer constants for the reductive quenching of the excited complexes is difficult. Nevertheless, the study emphasises the possibility to obtain [ReX(CO)(3)(diimine)] complexes with a wide range of physicochemical properties by ligand variations and the great potential of compounds of this class of complexes as inorganic photosensitisers.
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| 23. |
- Kurz, Philipp, et al.
(författare)
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Redox reactions of a dinuclear manganese complex : the influence of water
- 2008
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :5, s. 762-770
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Tidskriftsartikel (refereegranskat)abstract
- The redox properties of the dinuclear manganese complex [(Mn2L)-L-III,III(mu-OAC)(2)](+) (1) (where L is the trianion of the heptadentate ligand 2,6-bis{[(3,5-di-tert-butyl-2-hydroxybenzyl)(2-pyridylmethyl)amino]methy l)-4-methylphenol) were studied in acetonitrile solutions containing different concentrations of water. Electrochemical reactions as well as reactions with different chemical and photochemical redox reagents were monitored, using a variety of analytical techniques, namely cyclic voltammetry, UV/Vis spectroelectrochemistry, and EPR spectroscopy. We found that even small concentrations of water influence the compound's redox behaviour significantly, especially the oxidation reactions. As a consequence, the presence of water reduces the overall potential span needed to reach the highest oxidation state observed for 1 (M-2(III,IV)) from its most reduced state (Mn-2(II,II)) to about 1.1 V Higher oxidation states of I are stabilized, most likely by water coordination and the formation of mu-oxido bridge(s) between the two manganese atoms. For reducing conditions, an unprecedented 25-line EPR signal was observed, which might originate from reduced 1 in its Mn-2(II,II) or Mn-2(II,II) state after considerable ligand rearrangement. As complexes like I have been designed to act as potential water oxidation catalysts, the complicated redox- and ligand-exchange chemistry found for 1 in the presence of water, its intended substrate, might be exemplary for many of the dinuclear manganese compounds currently under investigation.
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| 24. |
- Kuznetsov, Alexei N., et al.
(författare)
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Synthesis of main group polycations in molten and pseudo-molten GaBr3 media
- 2005
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :24, s. 4907-4913
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Tidskriftsartikel (refereegranskat)abstract
- The prospects of synthesizing polycationic species using GaBr3 in benzene solution at room temperature have been investigated. The salts Bi-8[GaBr4](2), Sb-8[GaBr4](2) and Te-4- [Ga2Br7](2) have been isolated and characterized. The first two compounds are isotypic with Sb-8[GaCl4](2), crystallize in the space group Pna2(1), and feature square anti-prismatic E-8(2+) polycations (E = Sb, Bi). Unit-cell parameters for Bi-8[GaBr4](2) are a = 18.3014(10) angstrom, b = 10.3391(6) angstrom and c = 13.5763(7) angstrom, and for Sb-8[GaBr4](2); a = 18.096(2) angstrom, b = 10.1572(9) angstrom and c = 13.2168(10) angstrom. Te-4[Ga2Br7](2) crystallizes in the space group P2(1)/c with a = 10.1600(9) angstrom, b = 10.8314(9) angstrom, c = 13.8922(10) angstrom and beta = 99.182(7)degrees, and features a square-planar Te-4(2+) polycation. The compound Bi-5[GaBr4](3) has been synthesized from molten GaBr3 and characterized by using powder diffractometry in space group Fm-3c; a = 17.6263(8) angstrom. The structure model for this compound suggests the included Bi-5(3+) cations to be practically freely oriented within its cavities in the solid phase.
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| 25. |
- Li, P., et al.
(författare)
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Influence of tertiary phosphanes on the coordination configurations and electrochemical properties of iron hydrogenase model complexes : Crystal structures of (mu-S2C3H6)Fe-2(CO)(6-n)L-n (L = PMe2Ph, n=1, 2; PPh3 P(OEt)(3), n=1)
- 2005
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :12, s. 2506-2513
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Tidskriftsartikel (refereegranskat)abstract
- A series of mono- and disubstituted diiron complexes [(mu-pdt)-Fe-2(CO)(5)L] [pdt = 1,3-propanedithiolato; L = PMe3 (2), PMe2Ph (3), PPh3 (4), P(OEt)(3) (5)] and [(mu-pdt)Fe-2(CO)(4)L-2] [L = PMe2Ph (6), PPh3 (7), P(OEt)3 (8)] were prepared as Fe-only hydrogenase-active-site models by controllable CO displacement of [(mu-pdt)Fe-2(CO)(6)] by tertiary phosphanes. The coordination configurations of 3-6 were characterized by X-ray crystallography. Disubstituted diiron complex 6 features an apical/apical coordination mode, instead of the typical transoid basal/basal configuration. The electrochemistry of 2-6 and 8 was studied by cyclic voltammetry to evaluate the effects of different tertiary phosphane ligands on the redox properties of the iron atoms of model complexes.
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| 26. |
- Li, Ping, et al.
(författare)
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Phosphane and phosphite unsymmetrically disubstituted diiron complexes related to the Fe-only hydrogenase active site
- 2007
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :23, s. 3718-3727
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Tidskriftsartikel (refereegranskat)abstract
- A series of unsymmetrically disubstituted diiron complexes [(mu-pdt){Fe(CO)(2)L-1]{Fe(CO)(2)L-2}] [pdt = 1,3-propanedithiolato; L-1 = PMe3, L-2 = PMe2Ph, 4; PPh3, 5; PCy3, 6; P(OEt)(3), 7; L-1= PMe2Ph, L-2 = PPh3, 8; P(OEt)(3), 9; L-1 = P(OEt)(3), L-2 = PPh3, 10; PCy3, 11] and [(mu-edt){Fe(CO)(2)PMe3)}{Fe(CO)(2)PPh3}] (edt = 1, 2-ethane dithiolato, 12) were prepared by means of step-wise CO displacements of [(mu-pdt)Fe-2(CO)(6)] and [(mu-edt)-Fe-2(CO)(6)] by different tertiary phosphane and phosphite ligands. The interconversion of the irondithiacyclohexane ring and the rotation of the [Fe(CO)(2)PR3] subunit were studied using by variable-temperature P-31{H-1} NMR spectroscopy of 4, 6 and 12 in solution. The molecular structures of 4-6, 8-10 and 12 show that complexes 4-6, 8, 9 and 12 possess an apical/basal coordination mode and complex 10 has an apical/apical conformation. The X-ray analyses indicate that the PMe2Ph ligand in the apical position of the starting complex [(mu-pdt){Fe(CO)(3)}{FeCO2(PMe2Ph)}] rotates to the basal position on conversion to the products 8 and 9. Cyclic voltammograms of 4-11 were studied both under argon and CO. The influences of the phosphane and phosphite ligands on the redox properties of the unsymmetrically disubstituted diiron complexes are discussed. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
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| 27. |
- Liao, Rong-Zhen, et al.
(författare)
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Theoretical study of the RNA hydrolysis mechanism of the dinuclear zinc enzyme RNase Z
- 2009
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Ingår i: European Journal of Inorganic Chemistry. - Weinheim : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :20, s. 2967-2972
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Tidskriftsartikel (refereegranskat)abstract
- RNase Z is a dinuclear zinc enzyme that catalyzes the removal of the tRNA 3'-end trailer. Density functional theory is used to investigate the phosphodiester hydrolysis mechanism of this enzyme with a model of the active site constructed on the basis of the crystal structure. The calculations imply that the reaction proceeds through two steps. The first step is a nucleophihc attack by a bridging hydroxide coupled with protonation of the leaving group by a Glu-His diad. Subsequently, a water molecule activated by the same Glu-His diad makes a reverse attack, regenerating the bridging hydroxide. The second step is calculated to be the rate-limiting step with a barrier of 18 kcal/mol, in good agreement with experimental kinetic studies. Both zinc ions participate in substrate binding and orientation, facilitating nucleophilic attack. In addition, they act as electrophilic catalysts to stabilize the pentacoordinate trigonal-bipyramidal transition states.
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| 28. |
- Lindsjo, Martin, et al.
(författare)
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Bi16I4 - A New Bismuth Subiodide : An Analysis of Molecular Packing and Electronic Structures of the Compounds in the BimI4 (m=14, 16, 18) Family
- 2008
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :33, s. 5196-5202
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Tidskriftsartikel (refereegranskat)abstract
- A new bismuth subiodide Bi16I4 was synthesized by hightemperature synthesis. Its structure was determined by single-crystal X-ray diffraction analysis [C2/m (No. 12), a = 25.948(6) angstrom, b = 4.354(1) angstrom, c = 13.259(3) angstrom, beta = 104.48(2)circle, Z = 2, R-1 = 0.041, wR(all)(F-2) = 0.109]. The compound belongs to the BimI4 (m = 14, 16, 18) family of low-dimensional subhalides that feature one-dimensional bismuth stripes of varying width, terminated by iodine atoms. Ab initio calculations at the I)FT level were performed on 31) structures of all three BimI4 compounds of the family. According to the computational data all three compounds are expected to exhibit metallic behavior and Pauli paramagnetism, with a directional anisotropy of the properties indicated by the calculated band structures. The molecular packing in bismuth subiodides has been analyzed in detail and two homologous series - Bi8+4nI4 and Bi10+4nI4 (n = 0, 1, 2, ...) - are suggested to describe existing and possible structures of the compounds of the BimI4 family. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
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| 29. |
- Lindsjö, Martin, et al.
(författare)
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Improvements of and insights into the isolation of bismuth polycations from benzene solution - Single-crystal structure determinations of Bi-8[GaCl4](2) and Bi-5[GaCl4](3)
- 2005
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; 2005:4, s. 670-675
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis, crystal growth and structure are reported for the two salts Bi-5[GaCl4](3) and Bi-8[GaCl4](2). The compounds are prepared from a solution of BiCl3 and GaCl3 in benzene, using gallium metal as reducing agent. Bi-8[GaCl4](2) contains a Bi-8(2+) polycation that, essentially, adopts an ideal square antiprismatic geometry. The compound crystallizes in the P6(3) space group; a = 17.760(2) Angstrom and c = 12.979(3) Angstrom. Bi-5[GaCl4](3) crystallizes in the R3c space group, a = 11.814(2) Angstrom, c = 29.974(3) Angstrom, and contains a Bi-5(3+) cation adopting a trigonalbipyramidal geometry. The cation is slightly distorted from the ideal D-3h symmetry.
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| 30. |
- Ma, Ming-Guo, et al.
(författare)
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Solvothermal Synthesis and Characterization of Hierarchically Nanostructured Hydroxyapatite Hollow Spheres
- 2009
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley-VCH Verlag GmbH & Co. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :36, s. 5522-5526
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Tidskriftsartikel (refereegranskat)abstract
- Hierarchically nanostructured hydroxyapatite (HA) hollow spheres assembled from nanorods have been successfully synthesized using CaCl2, NaH2PO4, and potassium sodium tartrate via a solvothermal method at 200 °C for 24 h in water/N,N-dimethylformamide (DMF) mixed solvents. The ratio of water to DMF plays a key role in the formation of hierarchically nanostructured HA hollow spheres. The potassium sodium tartrate was used as a chelating ligand and a template molecule in the synthesis and self-assembly of HA nanorods. The products were characterized by X-ray powder diffraction, and field-emission scanning electron microscopy (FESEM), transmission electron microscopy, high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectra (EDS), Brunauer-Emmett-Teller (BET), and Fourier transform infrared spectrometry. FESEM and TEM images indicated that hollow spheres of about 3.6 μ m in diameter were built by HA nanorods. On the basis of experimental results, a possible formation mechanism of these hierarchically nanostructured HA hollow spheres in the growth processes was proposed.
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| 31. |
- Nurkkala, Lasse, et al.
(författare)
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The effects of pendant vs. fused thiophene attachment upon the luminescence lifetimes and electrochemistry of tris(2,2 '-bipyridine)ruthenium(II) complexes
- 2008
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Ingår i: European Journal of Inorganic Chemistry. - Weinheim : Wiley-VCH Verlag GmbH. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :26, s. 4101-4110
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Tidskriftsartikel (refereegranskat)abstract
- The electrochemical and photophysical properties for a range of ruthenium(II) tris-2,2’-bipyridine complexes in which a thiophene substituent is attached to one of the bipyridine ligands via either a pendant or a fused mode have been determined. The fused mode of attachment eliminates torsional movement between the thiophene unit and the chelating bipyridine, thereby offering optimal overlap between the p systems of the chelating unit and the attached thiophene unit. The electrochemical properties of these complexes were found to be similar, however the luminescence lifetimes and intensities (in CH3CN at room temperature) were found to be correlated to the mode of attachment. The longest luminescence lifetime wasobserved for the complex [Ru(bpy)2(4-thiophen-2-yl-[2,2']-bipyridine)]2+ (3000 ns), as compared to the prototypic [Ru(bpy)3]2+ (1745 ns). This complex also had the highest quantum yield (0.045). In the four isomeric complexes where the thiophene ring was fused to the b or c face of the pyridine the lifetimes fell in the interval 275-1510 ns and the quantum yield ranged between 0.0047-0.014. (© WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
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| 32. |
- Nyhlén, Jonas, et al.
(författare)
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"Frustration" of orbital interactions in Lewis base/Lewis acid adducts: a computational study of H2 uptake by phosphanylboranes R2P=BR'2
- 2009
-
Ingår i: European Journal of Inorganic Chemistry. - Weinheim : Wiley-VCH Verlag GmbH & Co. KGaA. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :19, s. 2759-2764
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Tidskriftsartikel (refereegranskat)abstract
- The reaction of mol. hydrogen with phosphanylboranes R2P:BR'2 (1) is systematically studied by d. functional theory calcns. and second order Moller-Plesset perturbation theory. The potential energy barriers and the exothermicity of H2 uptake are reported for a series of phosphanylboranes with different electron-donating and -withdrawing groups bound to phosphorus and boron. Systematic MO anal. reveals that the "frustration" between boron and phosphorus can be increased by modifying the substituents, and thus, AO interactions could be exploited in order to increase the reactivity of 1. Addnl., authors found a correlation between the potential energy barrier for H2 uptake and the energy of the HOMO of the P:B complex, which could be relevant for the prediction of the properties of candidate compds. for H2 activation and therefore useful for the development of such systems. [on SciFinder(R)]
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| 33. |
- Olsson, Lars-Fride, et al.
(författare)
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In vitro formation of nanocrystalline carbonate apatite - A structural and morphological analogue of atherosclerotic plaques
- 2007
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :26, s. 4123-4127
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Tidskriftsartikel (refereegranskat)abstract
- The in vitro formation of carbonate apatite in solutions with ion concentrations comparable to those in human serum was studied. The composition and morphology of the resulting apatite precipitate displayed a hierarchical assembly of elongated plate-shaped nanocrystals of carbonate apatite analogous to previously characterized bioapatites formed in The main conclusion is that so-called bioapatites may form in vitro and that precipitation inhibitors most likely are essential for the prevention of spontaneous calcification at normal human serum ion concentrations.
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| 34. |
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| 35. |
- Rosdahl, Jan, et al.
(författare)
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On the Structure of Sn9(4-) Cluster in Liquid and Solid State
- 2005
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :14, s. 2888-2894
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Tidskriftsartikel (refereegranskat)abstract
- The nonastannide clusters have been investigated usingEXAFS, NMR and Raman spectroscopy as well as quantum chemical calculations explicitly considering a model cationic field and solid-state statistics. NMR spectroscopic andEXAFS results are basically identical to those previously published and consistent with a fluctional model of the cluster. The quantum chemical calculations show that there is no significant difference in energy between the two model geometries, C4v and D3h, and that the vibrational frequencies are very low, clearly indicating that the cluster is expected to be fluctional. The solid-state statistics show that both model geometries can be used to describe all known nonastannide structures with reasonable success, illustrating that the classification of the nonastannide clusters in terms of specific symmetries is entirely arbitrary.
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| 36. |
- Sun, Hongfei, et al.
(författare)
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Effect of deprotonation of a benzimidazolyl ligand on the redox potential and the structures of mononuclear ruthenium(II) complexes
- 2007
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :26, s. 4128-4131
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Tidskriftsartikel (refereegranskat)abstract
- A monoruthenium(II) complex of the benzimidazolyl ligand and its deprotonated counterpart were prepared and structurally characterized. The reversible protonation/deprotonation process of the ancillary ligand switches the redox potential of the ruthenium(II) core from 0.69 to 0.26 V vs. Ag/AgNO3. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
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| 37. |
- Tobin, Gerard, et al.
(författare)
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What is the current evidence for antigen involvement in the development of chronic lymphocytic leukemia?
- 2006
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Ingår i: Hematological Oncology. - : Wiley. - 0278-0232 .- 1099-1069. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- For many years it has been evident that B-cell chronic lymphocytic leukemia (CLL) displays preferential usage of individual immunoglobulin (Ig) variable heavy chain (VJapanese sourceH) genes. The VH1-69 gene was the first to be reported overrepresented in a large number of CLL patients, where the VH1-69+ CLL rearrangements showed characteristic molecular features, such as unmutated VH genes, usage of specific diversity/joining gene segments, and a longer than average complementarity determining region (CDR) 3 with certain common amino acid motifs. Also, biased usage of the VH3-07 and VH4-34 genes with specific rearrangement characteristics was reported in CLL. These findings led to the speculation that antigens could be involved during CLL development by triggering proliferation of B-cells with specific B-cell receptors (BCRs) leading to an increased risk of transforming events. Recently, we characterized a subset of CLL utilizing the VH3-21 gene that also displayed peculiar Ig features, e.g. very short and homologous CDR3s, predominant λ expression and preferential Vλ2-14 gene usage. This VH3- 21+ subgroup also had poor prognosis despite the fact that two-thirds of cases carried mutated VH genes. Moreover, we and others have thereafter described further CLL subsets with very similar heavy and light chain gene rearrangement features. These latter findings of subsets expressing restricted BCRs have emphasized the hypothesis that antigens could play a role during the pathogenesis of CLL. Interestingly, recombinant antibodies produced from these restricted subsets showed similar cytoplasmatic reactivity within each group, thus suggesting recognition of a limited number of autoantigens. Further characterization of antigens is now necessary in order to understand their nature and exact role in CLL development.
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| 38. |
- Wentz, Elisabet, 1964, et al.
(författare)
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Brief report: Decreased bone mineral density as a long-term complication of teenage-onset anorexia nervosa.
- 2007
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Ingår i: European Eating Disorders Review. - : Wiley. - 1099-0968 .- 1072-4133. ; 15:4, s. 290-295
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To follow up bone mineral density (BMD) 4 years after decreased BMD was diagnosed in adult individuals with teenage-onset anorexia nervosa (AN). METHOD: In a previous study BMD was assessed in 39 individuals (36 women, 3 men) 11 years after AN onset. Decreased BMD occurred in a minority. In the present study, a 4-year follow-up of individuals with decreased BMD, 11 AN women were reassessed by using dual energy X-ray absorptiometry (DXA). Two women still had an eating disorder (ED). RESULTS: Eight out of eleven women met criteria for decreased BMD/osteoporosis. There was an increase in BMD of total body and lumbar spine (LS). There was a relationship between lumbar BMD and BMI. CONCLUSION: At follow-up of decreased BMD in adult women with teenage-onset of AN, there is a possibility of improvement of BMD.
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| 39. |
- Abu-Youssef, Morsy A.M., et al.
(författare)
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1D and 2D FeII Azide Coordination Polymers with Ferromagnetic Canting
- 2008
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-0682. ; 2008:1, s. 112-118
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Tidskriftsartikel (refereegranskat)abstract
- The two compounds [FeII(pyridine)2(N3)2(H2O)] (1) and [FeII(4-acetylpyridine)2(N3)2] (2) were prepared. The X-ray crystal structures show end-to-end (EE) bridging azides in both cases with a 1D Fe-NNN-Fe chain for 1 and a 2D Fe-NNN-Fe net in 2. Both compounds show similar magnetic behaviour where the high-temperature data are consistent with antiferromagnetic couplings and the low-temperature data indicate ferrimagnetic ordering based on spin canting at 20 and 45 K. Compound 2 also shows a hysteresis loop. These findings are compared to the related 3D coordination polymer [Fe(N3)2(4,4'-bipyridine)]. According to network analyses the latter compound was shown to contain the new uninodal six-connected-network topology (510 · 64 · 7)-jsm.
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| 40. |
- Abu-Youssef, Morsy A. M., et al.
(författare)
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New Polymeric Manganese Azide Derivatives with Quinazoline
- 2005
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Ingår i: European Journal of Inorganic Chemistry. - 1434-1948 .- 1099-0682. ; 2005:22, s. 4659 - 4664
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Tidskriftsartikel (refereegranskat)abstract
- Two new polymeric derivatives of the (azido)MnII system with formula [Mn(H2O)(μ-N3)(N3)(quinaz)2]n (1) and [Mn(μ-N3)2(quinaz)2]n (2) (quinaz = quinazoline) have been structurally and magnetically characterised. Compound 1 crystallises in the triclinic system, space group P-1, and consists of 1D chains with single end-to-end azido bridges. These chains give a two-dimensional supramolecular arrangement by means of H-bond interactions. Compound 2 crystallises in the monoclinic system, space group C2/c, and contains a square alternating 2D network bridged by azido ligands in the end-to-end coordination mode. Compound 2 exhibits some unusual features, such as the unprecedented linear coordination of the azido bridge. Magnetic analysis reveals moderate antiferromagnetic coupling, with J values in good agreement with the expected range, as a function of the Mn-N-N bond angles.
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| 41. |
- Deeming, AJ, et al.
(författare)
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Mechanisms of concurrent hydride migration processes in a triruthenium cluster capped by a phenylphosphinidene (PPh) ligand
- 2005
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1099-0682 .- 1434-1948. ; :21, s. 4352-4360
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Tidskriftsartikel (refereegranskat)abstract
- Two methods were used to synthesise [Ru-3(mu-H)(2)(mu(3)-PPh)-(CO)(7) (mu-dppm)] (3) (dppm = Ph2PCH2PPh2), the subject of this paper. Treatment of [Ru-3(CO)(10)(mu-dppm)] (1) with phenylphosphane in refluxing THF gave both [Ru-3(mu-H)(2)(mu-PHPh)-(CO)(8)(mu-dppm)] (2) and [Ru-3(mu-H)(2)(mu(3)-PPh)(CO)(7)(mu-dppm)] (3). Cluster 2 converts to 3 in refluxing THF. Alternatively the phenylphosphinidene cluster [Ru-3(mu-H)(2)(mu(3)-PPh)(CO)(9)] (4), prepared by the reported method of treating [Ru-3(CO)(12)] with phenylphosphane, reacts with dppm to produce cluster 3. The single-crystal X-ray structures of 2 and 3 are reported. Hydride mobility in [Ru-3(mu-H)(2)(mu(3)-PPh)(CO)(7)(mu-dppm)] (3) was analysed by variable-temperature H-1 and P-31(H-1) NMR methods. The variations in the spectra with temperature could not be interpreted by a single process, several of which were explored and which gave inadequately matching computed and experimental spectra. However, the spectra were successfully analysed by two concurrent processes, both involving the migration of hydride ligands between Ru-Ru edges. The faster process leads to the exchange of the nonequivalent phosphorus nuclei but not hydride exchange, whereas the hydrides are also exchanged in the slower process. Both processes require hydride ligand migration from one Ru-Ru edge to a vacant one. The hydride ligand bridging the same pair of ruthenium atoms as the dppm ligand is the slower to migrate.
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| 42. |
- Gorzsás, András, et al.
(författare)
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On the Fate of Vanadate in Human Blood
- 2006
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-0682. ; 18, s. 3559-65
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Tidskriftsartikel (refereegranskat)abstract
- The cover picture shows a symbolic representation of the fate of vanadate in human blood. Since the transition metal vanadium is named after Vanadis, the Nordic goddess of beauty, she is represented by the famous Venus de Milo sculpted in metal. Her cloth is decorated with the functional groups of the ligands that can form a complex (dress) with the metal while travelling in the blood vessels, the latter being symbolised by the caverns in the background. The water in the caves represents the aqueous solutions in which speciation studies have been carried out in the group of Professor Lage Pettersson. Further references to these studies are found as cave paintings on the walls: a distribution diagram and a set of 51V NMR spectra. The studies have been carried out in the framework of the COST D21/009 working group. The geographical locations of the research groups within this working group are shown by illuminated dots on the map of Europe in the background. The goal of the studies was to better understand the ability of vanadium to lower blood glucose levels (represented by the sugar cubes washed ashore on the left) and thus its potential as an orally applicable drug against diabetes. A Microreview, covering the results of the above mentioned speciation studies dealing with the fate of vanadate in human blood, is represented by A. Gorzsás, I. Andersson, and L. Pettersson on p. 3559 ff. The digital artwork for this cover was created by András Gorzsás.
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| 43. |
- Kiriakidou-Kazemifar, Nitsa, et al.
(författare)
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Syntheses and fluxional processes of diphenyl(2-thienyl)phosphane derivatives of triosmium clusters
- 2006
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1099-0682 .- 1434-1948. ; :10, s. 2058-2068
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Tidskriftsartikel (refereegranskat)abstract
- Thermal treatment of [OS3(CO)(12)] with diphenyl(2-thienyl)phosphane, Ph(2)p(C4H3S), results in the formation of [Os-3(CO)(12-x){Ph2P(C4H3S)}(x)] (x = 1-3, 1-3), but no C-H bond activation was observed. Reaction of [H2Os3(CO)(10)] with diphenyl(2-thienyl)phosphane at ambient temperature affords [HOs3(mu-H)(CO)(10){Ph2P(C4H3S}] (4), but when the same reaction is repeated at elevated temperatures, the cyclometallated species [(mu-H)Os-3(CO)(9){mu(3)-Ph(2)p(C4H2S)}] (5) and [mu-H) Os-3(CO)(8){mu 3-Ph2P(C4H2S)}(Ph2P(C4H3S)}] (6) are formed. In addition, two more products, tentatively assigned as [(mu-H)Os-3(CO)(6()mu(3)-Ph2P(C4H2S)}{mu-Ph2P(C4H3S)}{Ph2P-(C4H3S)}] (7) and [(mu-H)Os-3 (CO)(7) {mu-Ph2P(C4H2S)}] (4)tPh(2)P(C(4)H3(S)))(Ph2P(C4H3S))] (8) are obtained. The dynamic behaviours of 2, 5 and 6 have been studied by variable-temperature (VT) and H-1 P-31{H-1} NMR spectroscopy. The VT P-31{H-1} NMR spectra of [Os-3(CO)(10){Ph2P(C4H3S)}(2)] (2) demonstrate that a mixture of two isomers, which are in rapid exchange at room temperature, is present and that the less common cis-trans isomer, whose structure has been determined by X-ray crystallography, is favoured for this cluster. The VT H-1 NMR spectra of 5 indicate the presence of two isomers which are proposed to arise from an oscillation of the sigma,eta(2)-vinyl group of the thienyl moiety between two metal atoms. A similar fluxional process is proposed to occur in 6 and the assignment of the room-temperature structure(s) of this cluster was confirmed by H-1-Os-187 2D HMQC spectroscopy. In addition to 2, the solid-state structures of 3, 5 and 6 have been determined by X-ray crystallography. (c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006.
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| 44. |
- Kopel, Pavel, et al.
(författare)
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Ferromagnetic Properties of a Trinuclear Nickel(II) Complex with a Trithiocyanurate Bridge
- 2009
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Ingår i: European Journal of Inorganic Chemistry. - 1434-1948 .- 1099-0682. ; 2009:36, s. 5475-5482
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Tidskriftsartikel (refereegranskat)abstract
- A novel trinuclear nickel(II) complex with N,N,N',N'',N''-pentamethyldiethylenetriamine (pmdien) and a trithiocyanurate(3-) (ttc3-) bridge of composition [Ni3(pmdien)3(μ-ttc)](ClO4)3 (1) was prepared. The X-ray crystal structure of 1 was determined, revealing the tris-N,S chelating mode of the trithiocyanurate bridge, forming a regular triangular NiII3 core. A deformed trigonal bipyramidal arrangement of the central atoms was further achieved by coordination of three pmdien N atoms. The complex shows a ferromagnetic exchange interaction among the NiII magnetic centers that is tuned by single-ion anisotropy and/or antisymmetric exchange. The complex orders ferromagnetically at Tc = 10 K and exhibits spin-glass properties.
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| 45. |
- Steen, Robert O., et al.
(författare)
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The role of isomeric effects on the luminescence lifetimes and electrochemistry of oligothienyl-bridged dinuclear tris(2,2′-bipyridine) ruthenium(II) complexes
- 2008
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-0682. ; :11, s. 1784-1794
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Tidskriftsartikel (refereegranskat)abstract
- The luminescence lifetimes (in CH 3CN at room temperature) and electrochemical potentials (in CH 3CN) of a range of mono- and bis(bidentate) 2,2′-bipyridine-capped oligothiophene-bridged Ru II complexes based on the 6-(2-thienyl)-2,2′-bipyridine and 4-(2-thienyl)-2,2′-bipyridine motifs have been measured. The redox potentials occurred in a very narrow range and showed only small shifts from that of [Ru(bpy) 3] 2+, which indicates that the inductive effects of the substituents on the 2,2′-bipyridine ligands are very similar across this series. In the complexes that incorporated a bithiophene moiety the oxidation of the bithienyl group occurred at higher potentials than the metal-centered Ru III/II oxidation. No or very weak interaction between the metal cores in the dinuclear complexes was observed. It was found that the luminescence lifetimes of the complexes where the attachment point of the oligothiophene bridge is in the 4-position of a 2,2′-bipyridine ligand were extended compared to [Ru(bpy) 3] 2+, whereas the luminescence was very short-lived (<30 ns) or completely quenched in the complexes where the oligothiophene bridge was attached in the 6-position. The difference in lifetimes is probably due to steric interactions between the thienyl bridge and the auxiliary bipyridyl ligands, resulting in disturbances in coordination symmetry of the metal core.
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| 46. |
- Werndrup, Pia, et al.
(författare)
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A Single-Source-Precursor Approach to Late Transition Metal Molybdate Materials: The Structural Role of Chelating Ligands in the Formation of Heterometallic Heteroleptic Alkoxide Complexes
- 2006
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-0682. ; 7, s. 1413-1422
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis and structural determination of three new heterometallic molybdenum complexes, one with cobalt and two with nickel and two of these with -diketonate ligands and one with amino alcohol ligands, are presented. The reaction of cobalt acetylacetonate with [MoO(OMe)4] provides [Co2Mo2O2(acac)2(OMe)10] (1) and [MoO(acac)(OMe)3] (4),and the reaction of nickel acetylacetonate with [MoO(OMe)4]provides [Ni2Mo2O2(acac)2(OMe)10] (2) and 4. The reaction of [Ni(ORN)2] (RN = CHMeCH2NMe2) with [MoO(OMe)4] yields [Ni2Mo2O2(ORN)2(OMe)10] (3). The two new oxomolybdenum complexes undergo ether elimination upon storage to give the corresponding dioxo complexes [MoO2(acac)(OMe)]2 (5) and [MoO2(ORN)(OMe)]2 (6). Compounds 3 and 4 could also be obtained from the reaction of stoichiometric amounts of Hacac with [MoO(OMe)4] and [MoO2(OMe)2], respectively. The local structure around the nickel atom in compound 2 in solution and compound 3 in the solid state and in toluene/hexane solution has been determined by means of EXAFS spectroscopy. The complexes are intended to be used as single-source precursors, which are attractive in coatings and for the preparation of mesoporous materials; its application for the synthesis of nickel molybdate by sol-gel processing is therefore reported. The oxide material obtained from 3 displays a uniform grain size and a large surface area.
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| 47. |
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| 48. |
- Chen, Shilu, et al.
(författare)
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Reaction mechanism of the binuclear zinc enzyme glyoxalase II : A theoretical study
- 2009
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Ingår i: Journal of Inorganic Biochemistry. - : Elsevier BV. - 0162-0134 .- 1873-3344. ; 103:2, s. 274-281
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Tidskriftsartikel (refereegranskat)abstract
- The glyoxalase system catalyzes the conversion of toxic methylglyoxal to nontoxic d-lactic acid using glutathione (GSH) as a coenzyme. Glyoxalase II (GlxII) is a binuclear Zn enzyme that catalyzes the second step of this conversion, namely the hydrolysis of S-d-lactoylglutathione, which is the product of the Glyoxalase I (GlxI) reaction. In this paper we use density functional theory method to investigate the reaction mechanism of GlxII. A model of the active site is constructed on the basis of the X-ray crystal structure of the native enzyme. Stationary points along the reaction pathway are optimized and the potential energy surface for the reaction is calculated. The calculations give strong support to the previously proposed mechanism. It is found that the bridging hydroxide is capable of performing nucleophilic attack at the substrate carbonyl to form a tetrahedral intermediate. This step is followed by a proton transfer from the bridging oxygen to Asp58 and finally C–S bond cleavage. The roles of the two zinc ions in the reaction mechanism are analyzed. Zn2 is found to stabilize the charge of tetrahedral intermediate thereby lowering the barrier for the nucleophilic attack, while Zn1 stabilizes the charge of the thiolate product, thereby facilitating the C–S bond cleavage. Finally, the energies involved in the product release and active-site regeneration are estimated and a new possible mechanism is suggested.
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| 49. |
- Clausén, Maria, et al.
(författare)
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Spectroscopic studies of aqueous gallium(III) and aluminum(III) citrate complexes
- 2005
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Ingår i: JOURNAL OF INORGANIC BIOCHEMISTRY. - : Elsevier BV. - 0162-0134. ; 99:3, s. 716-26
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Tidskriftsartikel (refereegranskat)abstract
- Aqueous gallium(III) citrate complexes have been studied in the 10(-2) M concentration range with extended X-ray absorption fine structure (EXAFS) and FTIR techniques. From EXAFS data, one mononuclear and one oligomeric species were identified at different Ga(III) to citrate ratios. The first shell of the mononuclear complex was found to be distorted, with average Ga-O bond lengths of 1.95 and 2.06 Angstrom, in agreement with the solid-state structure of Ga(Cit)(2)(3-) (Cit = citrate). Also the oligomeric species was found to have a distorted first shell, with average Ga-O bond lengths of 1.95 and 2.04 Angstrom. This complex was found to contain two Ga-Ga distances at 3.03 and 3.56 Angstrom, typical for edge and corner sharing GaO6 octahedra, respectively. The gallium(III) and aluminum(III) citrate systems were compared by means of FTIR, and were found to be analogous. The IR results suggest that the bond lengths derived from EXAFS for the 1:2 gallium(III) citrate complex also provide a good estimate of the corresponding distances in the mononuclear 1: 1 complex. Direct coordination of citrate to the metal ions in the oligomeric gallium(III) citrate complex was indicated from both EXAFS and IR results, and this complex is stoichiometrically analogous to the Al-3(H(-1)Cit)(3)(OH)(H2O)(4-) complex, which has been structurally determined. However, while the formation of the aluminum trimer has been shown to be slow, the gallium trimer was significantly more labile with a rate of formation indicated to be in the order of seconds or faster.
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| 50. |
- Dimitrakopoulou, Anastasia, et al.
(författare)
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Synthesis, structure and interactions with DNA of novel tetranuclear, [Mn-4(II/II/II/IV)] mixed valence complexes
- 2008
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Ingår i: Journal of Inorganic Biochemistry. - : Elsevier BV. - 1873-3344 .- 0162-0134. ; 102:4, s. 618-628
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Tidskriftsartikel (refereegranskat)abstract
- Reaction of Mn(II) with phenoxyalkanoic acids and di-2-pyridyl ketone oxime (Hpko) leads to neutral tetranuclear complexes of the general formula Mn-4(O)(pko)(4)(phenoxyalkanoato)(4) (phenoxyalkanoic acids: H-mcpa = 2-methyl-4-chloro-phenoxy-acetic acid, H-2,4,5-T = 2,4.5-trichloro-phenoxy-acetic acid or H3,4-D = 3,4-dichloro-phenoxy-acetic acid). The compounds were synthesized by adding di2-pyridyl ketone oxime to MnCl2 in the presence of the sodium salts of the alkanoic acids in methanol. The crystal structure of Mn-4(II/II/ II/IV)(O)(pko)4(()2,4,5-T)(4) . 2.5CH(3)OH . 0.25H(2)O 1 shows that the complex consists of a [Mn-4( mu(4)-O)](8+) core with a Mn(IV) and 3 Mn(II) ions in octahedral environment and a mu(4)-O atom bridging the four manganese ions. Spectroscopic studies of the interaction of these tetranuclear clusters with DNA showed that these compounds bind to dsDNA. The binding strength of the Mn-4(II/II/II/ IV)(O)(pko)(4)(2,4,5-T)(4) complex for calf thymus DNA is equal to 1.1 X 10(4) M-1. Among the deoxyribonucleotides they bind preferentially to deoxyguanylic acid (dGMP). Competitive studies with ethidium bromide (EthBr) showed that the Mn-4(II/II/II/ IV)(O)(pko)(4)(2,4,.5-T)(4) complex exhibited the ability to displace the DNA-bound EthBr indicating that the complex binds to DNA via intercalation in strong competition with EthBr for the intercalative binding site. Additionally, DNA electrophoretic mobility experiments showed that all three complexes, at low cluster concentration, are obviously capable of binding to pDNA causing its cleavage (relaxation) at physiological pH and temperature. At higher cluster concentration, catenated dimer forms of pDNA was formed.
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