| 1. |
- Smith, A., et al.
(författare)
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LunarEX-a proposal to cosmic vision
- 2009
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Ingår i: Experimental Astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 23:3, s. 711-740
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Tajkumar, T, et al.
(författare)
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Cervical carcinoma and sexual behavior: collaborative reanalysis of individual data on 15,461 women with cervical carcinoma and 29,164 women without cervical carcinoma from 21 epidemiological studies
- 2009
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Ingår i: Cancer Epidemiology Biomarkers & Prevention. - 1538-7755. ; 18:4, s. 1060-1069
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Tidskriftsartikel (refereegranskat)abstract
- High-risk human papillomavirus (HPV) types cause most cervical carcinomas and are sexually transmitted. Sexual behavior therefore affects HPV exposure and its cancer sequelae. The International Collaboration of Epidemiological Studies of Cervical Cancer has combined data on lifetime number of sexual partners and age at first sexual intercourse from 21 studies, or groups of studies, including 10,773 women with invasive cervical carcinoma, 4,688 women with cervical intraepithelial neoplasia grade 3 (CIN3)/carcinoma in situ, and 29,164 women without cervical carcinoma. Relative risks for invasive cancer and CIN3 were estimated by conditional logistic regression. Risk of invasive cervical carcinoma increased with lifetime number of sexual partners (P for linear trend <0.001). The relative risk for > or =6 versus 1 partner, conditioned on age, study, and age at first intercourse, was 2.27 [95% confidence interval (95% CI), 1.98-2.61] and increased to 2.78 (95% CI, 2.22-3.47) after additional conditioning on reproductive factors. The risk of invasive cervical carcinoma increased with earlier age at first intercourse (P for linear trend <0.001). The relative risk for age at first intercourse < or =14 versus > or =25 years, conditioned on age, study, and lifetime number of sexual partners was 3.52 (95% CI, 3.04-4.08), which decreased to 2.05 (95% CI, 1.54-2.73) after additional conditioning on reproductive factors. CIN3/carcinoma in situ showed a similar association with lifetime number of sexual partners; however, the association with age at first intercourse was weaker than for invasive carcinoma. Results should be interpreted with caution given the strong correlation between sexual and reproductive factors and the limited information on HPV status.
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| 3. |
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| 4. |
- Rajkumar, T, et al.
(författare)
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Carcinoma of the cervix and tobacco smoking: Collaborative reanalysis of individual data on 13,541 women with carcinoma of the cervix and 23,017 women without carcinoma of the cervix from 23 epidemiological studies - International collaboration of epidemiological studies of cervical cancer
- 2006
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136. ; 118:6, s. 1481-1495
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Tidskriftsartikel (refereegranskat)abstract
- Tobacco smoking has been classified as a cause of cervical cancer, but the effect of different patterns of smoking on risk is unclear. The International Collaboration of Epidemiological Studies of Cervical Cancer has brought together and combined individual data on 13,541 women with and 23,017 women without cervical carcinoma, from 23 epidemiological studies. Relative risks (RRs) and 95% confidence intervals (CIs) of carcinoma of the cervix in relation to tobacco smoking were calculated with stratification by study, age, sexual partners, age at first intercourse, oral contraceptive use and parity. Current smokers had a significantly increased risk of squamous cell carcinoma of the cervix compared to never smokers (RR = 1.60 (95% CI: 1.48-1.73), p < 0.001). There was increased risk for past smokers also, though to a lesser extent (RR = 1.12 (1.01-1.25)), and there was no clear trend with time since stopping smoking (p-trend = 0.6). There was no association between smoking and adenocarcinoma of the cervix (RR = 0.89 (0.74-1.06) and 0.89 (0.72-1.10) for current and past smokers respectively), and the differences between the RRs for smoking and squamous cell and adenocarcinoma were statistically significant (current smoking p < 0.001 and past smoking p = 0.01). In current smokers, the RR of squamous cell carcinoma increased with increasing number of cigarettes smoked per day and also with younger age at starting smoking (p < 0.001 for each trend), but not with duration of smoking (p-trend = 0.3). Eight of the studies had tested women for cervical HPV-DNA, and in analyses restricted to women who tested positive, there was a significantly increased risk in current compared to never smokers for squamous cell carcinoma (RR = 1.95 (1.43-2.65)), but not for adenocarcinoma (RR = 1.06 (0.14-7.96)). In summary, smokers are at an increased risk of squamous cell but not of adenocarcinoma of the cervix. The risk of squamous cell carcinoma increases in current smokers with the number of cigarettes smoked per day and with younger age at starting smoking.
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| 5. |
- Setiawan, Veronica Wendy, et al.
(författare)
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CYP17 genetic variation and risk of breast and prostate cancer from the national Cancer Institute Breast and Prostate Cancer Cohort Consortium (BPC3)
- 2007
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Ingår i: Cancer Epidemiology Biomarkers & Prevention. - 1538-7755. ; 16:11, s. 2237-2246
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Tidskriftsartikel (refereegranskat)abstract
- CYP17 encodes cytochrome p450c17 alpha, which mediates activities essential for the production of sex steroids. Common germ line variation in the CYP17 gene has been related to inconsistent results in breast and prostate cancer, with most studies focusing on the nonsynonymous single nucleotide polymorphism (SNP) T27C (rs743572). We comprehensively characterized variation in CYP17 by direct sequencing of exons followed by dense genotyping across the 58 kb region around CYP17 in five racial/ethnic populations. Two blocks of strong linkage disequilibrium were identified and nine haplotype-tagging SNPs, including T27C, were chosen to predict common haplotypes (R-h(2) >= 0.85). These haplotype-tagging SNPs were genotyped in 8,138 prostate cancer cases and 9,033 controls, and 5,333 breast cancer cases and 7,069 controls from the Breast and Prostate Cancer Cohort Consortium. We observed borderline significant associations with prostate cancer for rs2486758 [TC versus TT, odds ratios (OR), 1.07; 95% confidence intervals (95% Cl), 1.00-1.14; CC versus TT, OR, 1.09; 95% CI, 0.95-1.26; P trend = 0.04] and rs6892 (AG versus AA, OR, 1.08; 95% CI, 1.00-1.15; GG versus AA, OR, 1.11; 95% CI, 0.95-1.30; P trend = 0.03). We also observed marginally significant associations with breast cancer for rs4919687 (GA versus GG, OR, 1.04; 95% CI, 0.97-1.12, AA versus GG, OR, 1.17; 95% CI, 1.03-1.34; P trend = 0.03) and rs4919682 (CT versus CC, OR, 1.04; 95% CI, 0.97-1.12; TT versus CC, OR, 1.16; 95% CI, 1.01-1.33; P trend = 0.04). Common variation at CYP17 was not associated with circulating sex steroid hormones in men or postmenopausal women. Our findings do not support the hypothesis that common germ line variation in CYP17 makes a substantial contribution to postmenopausal breast or prostate cancer susceptibility.
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| 12. |
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| 13. |
- Heldring, N, et al.
(författare)
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Estrogen receptors: how do they signal and what are their targets
- 2007
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Ingår i: Physiological reviews. - : American Physiological Society. - 0031-9333 .- 1522-1210. ; 87:3, s. 905-931
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Tidskriftsartikel (refereegranskat)abstract
- During the past decade there has been a substantial advance in our understanding of estrogen signaling both from a clinical as well as a preclinical perspective. Estrogen signaling is a balance between two opposing forces in the form of two distinct receptors (ERα and ERβ) and their splice variants. The prospect that these two pathways can be selectively stimulated or inhibited with subtype-selective drugs constitutes new and promising therapeutic opportunities in clinical areas as diverse as hormone replacement, autoimmune diseases, prostate and breast cancer, and depression. Molecular biological, biochemical, and structural studies have generated information which is invaluable for the development of more selective and effective ER ligands. We have also become aware that ERs do not function by themselves but require a number of coregulatory proteins whose cell-specific expression explains some of the distinct cellular actions of estrogen. Estrogen is an important morphogen, and many of its proliferative effects on the epithelial compartment of glands are mediated by growth factors secreted from the stromal compartment. Thus understanding the cross-talk between growth factor and estrogen signaling is essential for understanding both normal and malignant growth. In this review we focus on several of the interesting recent discoveries concerning estrogen receptors, on estrogen as a morphogen, and on the molecular mechanisms of anti-estrogen signaling.
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| 14. |
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| 16. |
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| 19. |
- Cox, David G., et al.
(författare)
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A comprehensive analysis of the androgen receptor gene and risk of breast cancer: results from the National Cancer Institute Breast and Prostate Cancer Cohort Consortium (BPC3)
- 2006
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Ingår i: Breast Cancer Research. - : Springer Science and Business Media LLC. - 1465-5411 .- 1465-542X. ; 8:5
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Androgens have been hypothesised to influence risk of breast cancer through several possible mechanisms, including their conversion to estradiol or their binding to the oestrogen receptor and/ or androgen receptor ( AR) in the breast. Here, we report on the results of a large and comprehensive study of the association between genetic variation in the AR gene and risk of breast cancer in the National Cancer Institute Breast and Prostate Cancer Cohort Consortium ( BPC3). Methods The underlying genetic variation was determined by first sequencing the coding regions of the AR gene in a panel of 95 advanced breast cancer cases. Second, a dense set of markers from the public database was genotyped in a panel of 349 healthy women. The linkage disequilibrium relationships ( blocks) across the gene were then identified, and haplotypetagging single nucleotide polymorphisms ( htSNPs) were selected to capture the common genetic variation across the locus. The htSNPs were then genotyped in the nested breast cancer cases and controls from the Cancer Prevention Study II, European Prospective Investigation into Cancer and Nutrition, Multiethnic Cohort, Nurses' Health Study, and Women's Health Study cohorts ( 5,603 breast cancer cases and 7,480 controls). Results We found no association between any genetic variation ( SNP, haplotype, or the exon 1 CAG repeat) in the AR gene and risk of breast cancer, nor were any statistical interactions with known breast cancer risk factors observed. Conclusion Among postmenopausal Caucasian women, common variants of the AR gene are not associated with risk of breast cancer.
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| 20. |
- Cox, David G, et al.
(författare)
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Haplotypes of the estrogen receptor beta gene and breast cancer risk
- 2008
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136. ; 122:2, s. 387-392
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Tidskriftsartikel (refereegranskat)abstract
- Exposure to exogenous (oral contraceptives, postmenopausal hormone therapy) and endogenous (number of ovulatory cycles, adiposity) steroid hormones is associated with breast cancer risk. Breast cancer risk associated with these exposures could hypothetically be modified by genes in the steroid hormone synthesis, metabolism and signaling pathways. Estrogen receptors are the first step along the path of signaling cell growth and development upon stimulation with estrogens. The National Cancer Institute Breast and Prostate Cancer Cohort Consortium has systematically selected haplotype tagging SNPs in genes along the steroid hormone synthesis, metabolism and binding pathways, including the estrogen receptor beta (ESR2) gene. Four htSNPs tag the 6 major (>5% frequency) haplotypes of the ESR2 gene. These polymorphisms have been genotyped in 5,789 breast cancer cases and 7,761 controls nested within the American Cancer Society Cancer Prevention Study II, European Prospective Investigation into Cancer and Nutrition, Multiethnic Cohort, Nurses' Health Study and Women's Health Study cohorts. None of the SNPs were independently associated with breast cancer risk. One haplotype of the ESR2 gene was associated with breast cancer risk before correction for multiple testing (OR 1.17, 95% CI 1.07-1.28, p = 0.0007). This haplotype remained associated with breast cancer risk after adjustment for multiple testing using a permutation procedure. There was no statistically significant heterogeneity in SNP or haplotype odds ratios across cohorts. These data suggest that inherited variants in ESR2 (while possibly conferring a small increased risk of breast cancer) are not associated with appreciable (OR > 1.2) changes in breast cancer risk among Caucasian women.
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| 21. |
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| 22. |
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| 23. |
- Feigelson, HS, et al.
(författare)
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Haplotype analysis of the HSD17B1 gene and risk of breast cancer: A comprehensive approach to multicenter analyses of prospective cohort studies
- 2006
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Ingår i: Cancer Research. - 1538-7445. ; 66:4, s. 2468-2475
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Tidskriftsartikel (refereegranskat)abstract
- The 17 beta-hydroxysteroid dehydrogenase 1 gene (HSD17B1) encodes 17HSD1, which catalyzes the final step of estradiol biosynthesis. Despite the important role of HSD17B1 in hormone metabolism, few epidemiologic studies of HSD17B1 and breast cancer have been conducted. This study includes 5,370 breast cancer cases and 7,480 matched controls from five large cohorts in the Breast and Prostate Cancer Cohort Consortium. We characterized variation in HSD17B1 by resequencing and dense genotyping a multiethnic sample and identified haplotype-tagging single nucleotide polymorphisms (htSNP) that capture common variation within a 33.3-kb region around HSD17B1. Four htSNPs, including the previously studied SNP rs605059 (S312G), were genotyped to tag five common haplotypes in all cases and controls. Conditional logistic regression was used to estimate odds ratios (OR) for disease. We found no evidence of association between common HSD17B1 haplotypes or htSNPs and overall risk of breast cancer. The OR for each haplotype relative to the most common haplotype ranged from 0.98 to 1.07 (omnibus test for association: X-2 = 3.77, P = 0.58, 5 degrees of freedom). When cases were subdivided by estrogen receptor (ER) status, two common haplotypes were associated with ER-negative tumors (test for trend, Ps = 0.0009 and 0.0076; n = 353 cases). HSD17B1 variants that are common in Caucasians are not associated with overall risk of breast cancer; however, there was an association among the subset of ER-negative tumors. Although the probability that these ER-negative findings are false-positive results is high, these findings were consistent across each cohort examined and warrant further study.
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| 24. |
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| 25. |
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| 26. |
- Larsson, Anna-Carin, et al.
(författare)
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Solid state 31P and 207Pb MAS NMR studies on polycrystalline O,O′-dialkyldithiophosphate lead(II) complexes
- 2005
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Ingår i: Journal of magnetic resonance. - : Elsevier BV. - 1090-7807 .- 1096-0856. ; 177:1, s. 56-66
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Tidskriftsartikel (refereegranskat)abstract
- A number of lead(II) O,O′-dialkyldithiophosphate complexes were studied by 13C, 31P, and 207Pb MAS NMR. Simulations of 31P chemical shift anisotropy using spinning sideband analysis reveal a linear relationship between the SPS bond angle and the principal values δ22 and δ33 of the 31P chemical shift tensor. The 31P CSA data were used to assign ligands with different structural functions. In the cases of Adiethyldithiophosphate and di-iso-butyldithiophosphate lead(II) complexes, 2J (31P, 207Pb)-couplings were resolved and used to confirm the suggested assignment of the ligands. The SIMPSON computer program was used to calculate 31P and 207Pb spectral sideband patterns.
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| 27. |
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| 28. |
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| 29. |
- Mohlin, Frida, et al.
(författare)
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Scabies mite inactivated serine protease paralogs inhibit the human complement system.
- 2009
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Ingår i: Journal of immunology. - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 182:12, s. 7809-7817
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Tidskriftsartikel (refereegranskat)abstract
- Infestation of skin by the parasitic itch mite Sarcoptes scabiei afflicts 300 million people worldwide and there is a need for novel and efficient therapies. We have previously identified a multigene family of serine proteases comprising multiple catalytically inactive members (scabies mite-inactivated protease paralogs (SMIPPs)), which are secreted into the gut of S. scabiei. SMIPPs are located in the mite gut and in feces excreted into the upper epidermis. Scabies mites feed on epidermal protein, including host plasma; consequently, they are exposed to host defense mechanisms both internally and externally. We found that two recombinantly expressed SMIPPs inhibited all three pathways of the human complement system. Both SMIPPs exerted their inhibitory action due to binding of three molecules involved in the three different mechanisms which initiate complement: C1q, mannose-binding lectin, and properdin. Both SMIPPs bound to the stalk domains of C1q, possibly displacing or inhibiting C1r/C1s, which are associated with the same domain. Furthermore, we found that binding of both SMIPPs to properdin resulted in prevention of assembly of the alternative pathway convertases. However, the SMIPPs were not able to dissociate already formed convertases. Immunohistochemical staining demonstrated the presence of C1q in the gut of scabies mites in skin burrows. We propose that SMIPPs minimize complement-mediated gut damage and thus create a favorable environment for the scabies mites.
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| 30. |
- Rusanova, Daniela, et al.
(författare)
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Copper(I) O,O '-dialkyldithiophosphate clusters : EXAFS, NMR and X-ray diffraction studies
- 2007
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Ingår i: Journal of coordination chemistry (Print). - : Informa UK Limited. - 0095-8972 .- 1029-0389. ; 60:5, s. 517-525
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Tidskriftsartikel (refereegranskat)abstract
- Copper K- edge EXAFS data for six polycrystalline cubic cluster compounds, {Cu-8[ S2P(OR)(2)](6)(mu(8)- S)} with R= Et, Pr-n, Pr-i, Bu-n, Bu-i and Am-i, show that the architecture of their Cu-8(S2P)(2)S cores is fairly rigid and independent of both length and branching of the alkyl chain, and that the structure of the cluster is maintained in acetone solution. Solid- state P-31 CP-MAS and static Cu-65 NMR data for {Cu-8[S2P(O-n Pr)(2)] 6(mu(8)- S)} and {Cu-8[S2P(OEt)(2)](6) mu(8)- S)} show similarities in the icosahedral O,O'- dialkyldithiophosphate shells and in the `cubic' copper cores in these cluster compounds. The crystal structure of {Cu-8[S2P(O-n Pr)(2)](6) (mu(8)- S)} was resolved using single- crystal X- ray diffraction.
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| 31. |
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| 32. |
- Rusanova, Daniela, et al.
(författare)
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Formation of {Cu6[S2P(OC2H5)2]6} on Cu2S Surfaces from Aqueous Solutions of the KS2P(OC2H5)2 Collector: Scanning Electron Microscopy and Solid-State 31P Cross-Polarization/Magic Angle Spinning and Static 65Cu NMR Studies
- 2005
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 21:10, s. 4420-4424
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Tidskriftsartikel (refereegranskat)abstract
- The interactions of synthetic chalcocite surfaces with diethyldithiophosphate, potassium salt, K[S2P(OC2H5)2], were studied by means of 31P cross-polarization/magic angle spinning (CP/MAS) NMR spectroscopy and scanning electron microscopy (SEM). To identify the species formed on the Cu2S surfaces, a polycrystalline {CuI6[S2P(OC2H5)2]6} cluster was synthesized and analyzed by SEM, powder X-ray diffraction techniques and solid-state 31P CP/MAS NMR and static 65Cu NMR spectroscopy. 31P chemical shift anisotropy (CSA) parameters, CS and CS, were estimated and used for assigning the bridging type of diethyldithiophosphate ligands in the {CuI6[S2P(OC2H5)2]6} cluster. The latter data were compared to 31P CSA parameters estimated from the spinning sideband patterns in 31P NMR spectra of the collector-treated mineral surfaces: formation of polycrystalline {CuI6[S2P(OC2H5)2]6} on the Cu2S surfaces is suggested. The second-order quadrupolar line shape of 65Cu was simulated, and the NMR interaction parameters, CQ and Q, for the copper(I) diethyldithiophosphate cluster were obtained.
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| 33. |
- Rusanova, Daniela, et al.
(författare)
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Formation of Ο,Ο’-di-alkyl-dithiophosphate copper (I) complexes on the surface of synthetic chalcocite : NMR and SEM studies
- 2005
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Ingår i: Centenary of Flotation Symposium Proceedings. - : The Australian Institute of Mining and Metallurgy. - 9781920806316 ; , s. 581-590
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Konferensbidrag (refereegranskat)abstract
- The adsorption mechanism of three different 0,0'-di-alkyl-dithiophosphate (dtp) collectors, K[S22P(OR)2] with R = Et, i-Bu and i'-Amyl, on the surface of synthetic chalcocite (Cu2S)Was studied by means of solid-state 31P CP/MAS NMR spectroscopy. The morphology changes on the conditioned (Cu2S) surfaces, in the collector concentration range 0.1 - 10 mM, were also monitored with scanning electron microscope (SEM). In order to assign Cu(I)-dtp species on the surface of CU 2S, the corresponding bulk Cu(I)-dtp compounds, which are clusters of the monovalent copper containing either Cu6(antiprismatic) or Cu8(cubic) cores, were synthesised, and characterised by means of solid-state 31P CP/MAS and static 65Cu NMR. Further investigations on the crystal habits of the bulk systems were carried out by powder x-ray diffraction and SEM. A comparative analysis of the 31P chemical shift and chemical shift anisotropy (CSA) data estimated from the experimental NMR spectra of the polycrystalline bulk Cu(l) dialkyldithiophosphate complexes was used for assigning the 31P resonance lines in the NMR spectra of the collector treated CU2S powder samples. The species formed on the synthetic Cu2S surfaces were assigned to polycrystalline phases of: Cu6L6 with L = Et2dtp̄μ, Cu6L6, and Cu 8L6(S) with L = i'-Bu2dtp̄, and 3. Cu 8L6S) with L = i-Amyl2dtp̄. A heterophase autocatalytic step process of both formation and growth of solid Cu xLy (L = R2dtp, x = 6 or 8 and y = 6) complexes on the collector treated CU2S surface is proposed. A possible role of the oxidised form of dithiophosphate collectors, bis[di-alkyl-thiophosphoryl] -disulfane (disulfide), is discussed in terms of a specific self-redox reaction. The second order quadrupolar lineshapes in 65Cu NMR spectra were simulated and the interaction parameters, CQ and nQ, for the bulk dialkyldithiophosphato-copper(I) complexes were obtained
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| 34. |
- Rusanova, Daniela, et al.
(författare)
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Solid-state 31P CP/MAS and static 65Cu NMR characterization of polycrystalline copper(I) dialkyldithiophosphate clusters
- 2006
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Ingår i: Journal of magnetic resonance. - : Elsevier BV. - 1090-7807 .- 1096-0856. ; 179:1, s. 140-145
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Tidskriftsartikel (refereegranskat)abstract
- Polycrystalline tetra-nuclear Cu4[S2P(O-i-C3H7)2]4, hexa-nuclear Cu6[S2P(OC2H5)2]6, and octa-nuclear Cu8[S2P(O-i-C4H9)2]6(S) complexes were synthesized and analyzed by means of solid-state 31P CP/MAS and 65Cu static NMR spectroscopy. The symmetries of the electronic environments around each P-site were estimated from the 31P chemical shift anisotropy (CSA) parameters, Δaniso and η. The 65Cu chemical shift and quadrupolar splitting parameters obtained from the experimental 65Cu NMR spectra of the polycrystalline CuI-complexes are presented. A solid-state NMR approach for the elucidation of the stereochemistry of poly-nuclear Cu(I) dithiophosphate complexes, when the structural analysis of the systems by single-crystal X-ray diffraction is not readily available, is proposed.
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| 35. |
- Rusanova, Daniela, et al.
(författare)
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Solid-state NMR and EXAFS spectroscopic characterization of infoPolycrystalline copper(I) O,O prime -Dialkvldithiophosphate cluster compounds : Formation of copper(I) O,O prime -diisobutyklithiophosphate compounds on the surface of synthetic chalcocite
- 2006
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 12:20, s. 5282-5292
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Tidskriftsartikel (refereegranskat)abstract
- A number of polycrystalline copper(I) O,O-dialkyldithiophosphate cluster compounds with Cu4, Cu6, and Cu8 cores were synthesized and characterized by using extended X-ray absorption fine-structure (EXAFS) spectroscopy. The structural relationship of these compounds is discussed. The polycrystalline copper(I) O,O-diisobutyldithiophosphate cluster compounds, [Cu8{S2P(OiBu)2}6(S)] and [Cu6{S2P(OiBu)2}6], were also characterized by using 31P CP/MAS NMR (CP = cross polarization, MAS = magic-angle spinning) and static 65Cu NMR spectroscopies (at different magnetic fields) and powder X-ray diffraction (XRD) analysis. Comparative analyses of the 31P chemical-shift tensor, and the 65Cu chemical shift and quadrupolar-splitting parameters, estimated from the experimental NMR spectra of the polycrystalline copper(I) cluster compounds, are presented. The adsorption mechanism of the potassium O,O-diisobutyldithiophosphate collector, K[S2P(OiBu)2], at the surface of synthetic chalcocite (Cu2S) was studied by means of solid-state 31P CP/MAS NMR spectroscopy and scanning electron microscopy (SEM). 31P NMR resonance lines from collector-treated chalcocite surfaces were assigned to a mixture of [Cu8{S2P(OiBu)2}6(S)] and [Cu6{S2P(OiBu)2}6] compounds.
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| 36. |
- Rusanova, Daniela, et al.
(författare)
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Solid-state static 65Cu and 31P CP/MAS NMR, and liquid-state EXAFS studies on copper(I) O,O′-dialkyldithiophosphate cluster compounds : formation of the copper(I) O,O′-di-iso-amyldithiophosphate cluster compound on the surface of synthetic chalcocite
- 2006
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Ingår i: Polyhedron. - : Elsevier BV. - 0277-5387 .- 1873-3719. ; 25:18, s. 3569-3580
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Tidskriftsartikel (refereegranskat)abstract
- Polycrystalline octa-nuclear copper(I) O,O′-di-i-propyl- and O,O′-di-i-amyldithiophosphate cluster compounds, {Cu8[S2P(OR)2]6(μ8-S)} where R = iPr and iAm, were synthesized and characterized by 31P CP/MAS NMR at 8.46 T and static 65Cu NMR at multiple magnetic field strengths (7.05, 9.4 and 14.1 T). The symmetries of the electronic environments around the P sites were estimated from the 31P chemical shift anisotropy (CSA) parameters, δaniso and η. Analyses of the 65Cu chemical shift and quadrupolar splitting parameters for these compounds are presented with the data being compared to those for the analogous octa-nuclear cluster compounds with R = nBu and iBu. The 65Cu transverse relaxation for the copper sites in {Cu8[S2P(OiPr)2]6(μ8-S)} and {Cu8[S2P(OiAm)2]6(μ8-S)} was found to be very different, with a relaxation time, T2, of 590 μs (Gaussian) and 90 μs (exponential), respectively. The structures of {Cu4[S2P(OiPr)2]4} and {Cu8[S2P(OiPr)2]6(μ8-S)} cluster compounds in the liquid- and the solid-state were studied by Cu K-edge EXAFS. The disulfide, [S2P(OiAm)2]2, was obtained and characterized by 31P{1H} NMR. The interactions of the disulfide and of the potassium O,O′-di-i-amyldithiophosphate salt with the surfaces of synthetic chalcocite (Cu2S) were probed using solid-state 31P NMR spectroscopy and only the presence of copper(I) dithiophosphate species with the {Cu8[S2P(OiAm)2]6(μ8-S)} structure was observed.
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| 37. |
- Rusanova, Daniela, et al.
(författare)
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Spectroscopic characterization of the polycrystalline copper(I) di-n-butyldithiophosphate cluster - Cu8[S2P(O-n-Bu)2]6(μ8-S): Solid-state 31P CP/MAS and static 65Cu NMR studies
- 2006
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 259:12, s. 3903-3910
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Tidskriftsartikel (refereegranskat)abstract
- A polycrystalline copper(I) O,O′-di-n-butyldithiophosphate cluster compound, Cu8[S2P(O-n-Bu)2]6(μ8-S), was synthesized and characterized by 31P CP/MAS NMR at 8.46 T and static 65Cu NMR at multiple magnetic field strengths (7.05, 9.4 and 14.1 T). The principal values of the 31P chemical shift tensor and the 65Cu chemical shift and quadrupolar splitting parameters are presented. The data are compared to those for the analogous octa-nuclear cluster compounds [Cu8(S2P(OEt)2)6(μ8-S)], [Cu8(S2P(O-n-Pr)2)6(μ8-S)] and [Cu8(S2P(O-i-Bu)2)6(μ8-S)]. The transverse relaxation time constant, T2, for the [Cu8(S2P(O-n-Bu)2)6(μ8-S)] cluster compound was found to be 160 ± 8 μs. Possible intra-molecular motions in the cluster structures in terms of size and branching of the hydrocarbon chains are discussed as reasons for the different 65Cu NMR responses of the systems.
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| 44. |
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|
| 45. |
|
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| 46. |
|
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| 47. |
|
|
| 48. |
|
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| 49. |
|
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| 50. |
|
|
