| 1. |
- Ahmed, Mohammad Tofayel, et al.
(författare)
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Fabrication of new multifunctional cotton-modal-recycled aramid blended protective textiles through deposition of a 3D-polymer coating : high fire retardant, water repellent and antibacterial properties
- 2020
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 44:28, s. 12122-12133
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Tidskriftsartikel (refereegranskat)abstract
- This study reports a facile fabrication of multifunctional cotton-modal-recycled aramid blended protective textiles through the deposition of a three-dimensional tetrakis(hydroxymethyl)phosphonium chloride (THPC)-urea polymer coating. For this, blended fabrics with different compositions, weaving structures, thicknesses, GSMs and thread densities have been fabricated, followed by chemical deposition of the THPC-urea polymer coating on the fibrils of the yarn and then in the amorphous region through ammonia treatment. Full characterization of the resulting fabrics through SEM and FTIR allowed confirmation of the deposition of THPC-urea on each blended fabric. Treated and untreated samples were evaluated for their water repellency, flame retardance and antibacterial properties through diverse experimental tools. The results show that the lowest average char length (warp - 3.18 cm, weft - 2.84 cm) and radiant heat flux density (11.021 kW m-2), and highest LOI% (36.8%), were found in the 40%-cotton-30%-modal-30% aramid fabric, whereas the best thermal protective performance (t12- 4.0 s,t24- 5.9 s) was observed in the fabric with a high thickness and GSM. Regarding the water repellent properties, all treated samples showed superior water repellence properties expressed as water contact angle (thetaH2O) as high as 141.70 degrees to 151.50 degrees. Besides, the 3D polymer coating deposited on blended fabrics exhibited high antibacterial properties (99.90%) againstStaphylococcus aureusATCC 6538 andKlebsiella pneumoniaeATCC 4352 as calculated according to the KS K 0693:2016 method. These results herein provide fundamental grounds to design blended textiles with necessary functionalities for smart and protective applications.
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| 2. |
- Alammar, Tarek, et al.
(författare)
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Mechanochemical synthesis, luminescent and magnetic properties of lanthanide benzene-1,4-dicarboxylate coordination polymers (Ln(0.5)Gd(0.5))(2) (1,4-BDC)(3)(H2O)(4); Ln = Sm, Eu, Tb
- 2020
-
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 44:3, s. 1054-1062
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Tidskriftsartikel (refereegranskat)abstract
- Mechanochemical reactions of benzene-1,4-dicarboxylate (BDC2-) and lanthanide carbonates, Ln(2)(CO3)(3)center dot xH(2)O (Ln = Sm, Eu, Gd, Tb) yield phase pure lanthanide coordination polymers, (Ln(0.5)Gd(0.5))(2)(1,4-BDC)(3)(H2O)(4) with Ln = Sm, Eu, Tb, which are isostructural with Tb-2(1,4-BDC)(3)(H2O)(4) as confirmed by powder X-ray diffraction and vibrational spectroscopy. Upon excitation with UV light all three compounds display strong emissions, characteristic for the respective optically active lanthanide ion, namely, red for Eu3+, green for Tb3+ and orange-red for Sm3+. In case of the Tb3+-containing compound, the energy difference between the triplet energy level of benzene-1,4-dicarboxylate ligand (BDC2-) allows for the most efficient BDC2--Tb3+ energy transfer. As a consequence, an intense green luminescence with rather long lifetime (0.81 ms) and high quantum yield (22%) is observed after allowed excitation of the BDC2- ligand. The compounds are paramagnetic with no onset of long range magnetic ordering down to liquid He temperatures.
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| 3. |
- Almkvist, Gunnar, et al.
(författare)
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Distribution of iron and sulfur and their speciation in relation to degradation processes in wood from the Swedish warship Vasa
- 2011
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 35, s. 1491-1502
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Tidskriftsartikel (refereegranskat)abstract
- Wood samples from the Swedish warship Vasa were analysed by scanning electron microscopy and X-ray absorption spectroscopy with the focus on speciation and distribution of iron and sulfur compounds in the wood matrix. Both these elements were found at high concentration (10–100 mg/g) in the surface region as a result of former accumulation of iron sulfides, elemental sulfur and reduced organic sulfur species (ROSS). Below the surface region, iron was the dominating element (1–10 mg/g) present both as iron(II) and iron(III) compounds, which diffused into the wood matrix from corroding iron bolts and other iron items during the time in the sea (1628–1961). Electron microscopy results revealed that iron and sulfur are present in a variety of particles of different sizes and compositions in the surface region, in contrast to the interior where few particles were found. Here, the presence of iron compounds of nano-particle size inside the cell walls enables a close contact between the wood polymers and reactive oxygen species originating from reactions with iron compounds. The presence of ROSS seems to have played an important role as scavengers of reactive oxygen species. Samples with high iron : ROSS ratio displayed evident signs of degradation as indicated by depolymerisation of wood components accompanied by increased acidity due to low molecular organic acids. The observations strengthen the hypothesis of the pro-oxidative and antioxidant properties of iron and ROSS compounds, respectively, and that the chemical activities of these elements play crucial roles in the long term preservation of wooden maritime artefacts
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| 4. |
- Andreasson, Joakim, 1973, et al.
(författare)
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A simplicity-guided approach toward molecular set-reset memories
- 2010
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1369-9261 .- 1144-0546. ; 34:12, s. 2701-2703
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Tidskriftsartikel (refereegranskat)abstract
- Photochromic switches fulfill the general molecular design criteria for the surprisingly straightforward small-scale integration of seemingly complex set-reset latches. The implications of this re-interpretation are discussed with the example of a dithienylethene photochrome. The concept is shown to be valid for a multitude of well-introduced bistable switches with clearly differentiated output signals, e.g., optical signals for the presented example.
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| 5. |
- Arora, Kapildev K., et al.
(författare)
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Supramolecular synthesis of some molecular adducts of 4,4′-bipyridine N,N′-dioxide
- 2009
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Ingår i: New Journal of Chemistry. - 1144-0546 .- 1369-9261. ; 33:1, s. 57-63
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Tidskriftsartikel (refereegranskat)abstract
- Molecular adducts (1a–1e) of 4,4′-bipyridine N,N′-dioxide, 1, respectively with cyanuric acid, trithiocyanuric acid, 1,3,5-trihydroxybenzene (phloroglucinol), 1,3-dihydroxybenzene (resorcinol) and 1,2,4,5-benzenetetracarboxylic acid have been reported. The major interactions observed in the structures 1a–1e are N–H⋯O, N–H⋯S, O–H⋯O and C–H⋯O, in the form of homomeric and heteromeric patterns of the constituents, either as a single or cyclic hydrogen-bonded motifs. While in the adduct 1a, both homomeric and heteromeric units of both the constituents were observed, no heteromeric interactions were observed in 1b and 1c. In addition, in 1b, homomeric aggregation of molecules of 1 occurred in association with water molecules. However, while heteromeric interactions prevail between the constituents in 1d and 1e, only one of the co-crystallizing species gave homomeric interactions (4,4′-bipyridine N,N′-dioxide in 1d; 1,2,4,5-benzenetetracarboxylic acid in 1e). Further, in either type of the patterns, the cyclic motifs are formed as a pair-wise hydrogen bonds comprising of strong and weak hydrogen bonds (N–H⋯O/C–H⋯O or O–H⋯O/C–H⋯O). In three-dimensions, the ensembles of molecules yield planar sheets, ladders and pseudorotaxane type assemblies
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| 6. |
- Baryshnikov, Gleb V., et al.
(författare)
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A computational study of aromaticity and photophysical properties of unsymmetrical azatrioxa[8]circulenes
- 2017
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 41:7, s. 2717-2723
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Tidskriftsartikel (refereegranskat)abstract
- Owing to their potential use in organic light-emitting diodes and field-effect transistors we present a theoretical study of a series of unsymmetrical azatrioxa[8]circulenes in order to explain the impact of outer substituents and benzoannelation on photophysical constants and aromaticity of these compounds in terms of spin-orbit coupling perturbation and magnetically-induced ring currents. It is argued that the S1-Tn inter-system crossing processes constitute the main deactivation pathways for the fluorescence quenching, something that is supported by a good agreement obtained with experimental data on fluorescence quantum yields. The concept of the gauge-including magnetically induced currents has been applied in order to estimate the role of substituents and benzoannelated fragments on the aromaticity and particularly on the overall balance between the diatropic “aromatic” and paratropic “antiaromatic” current strengths. While a variation of the substituents in the outer perimeter of the studied circulenes does not provide a clear effect on their aromaticity, it is demonstrated that an additional benzoannelation (π-extension) of the azatrioxa[8]circulene macrocycle induces a significant aromaticity enhancement.
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| 7. |
- Baryshnikov, Gleb V., et al.
(författare)
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Substituent-sensitive fluorescence of sequentially N-alkylated tetrabenzotetraaza[8]circulenes
- 2017
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 41:15, s. 7621-7625
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Tidskriftsartikel (refereegranskat)abstract
- We explore the use of substituent-sensitive balance between fluorescence and non-radiative decay as a tool for optical tuning of promising materials for organic light emitting diode applications. A series of N-butylated tetrabenzotetraaza[8]circulenes is studied computationally in order to explain the gradual decrease of fluorescence intensity with the increase of the substituent number. The inter-system crossing probability is found to increase upon the gradual substitution of the circulene macrocycle as a result of the decrease of the S-1-T-1 energy gap due to the deformation of the tetrabenzotetraaza[8] circulenes and therefore the distortion of the pi-conjugation within the macrocycles. In contrast, the S-1-T-1 spin-orbit coupling matrix elements are quite insensitive to the number of outer substituents. As a result, the fluorescence-responsible pi pi(star) transition becomes less intense and the fluorescence rate constant decreases.
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| 8. |
- Bergdahl, Gizem Ertürk, et al.
(författare)
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Bisphosphonate Ligand Mediated Ultrasensitive Capacitive Protein Sensor : Complementary Match of Supramolecular and Dynamic Chemistry
- 2019
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 43:2, s. 847-852
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Tidskriftsartikel (refereegranskat)abstract
- Modern healthcare demands rapid and accurate detection of proteins/enzymes at the ultratrace level. Herein we present a molecularly imprinted capacitive sensor for Trypsin, developed by microcontact imprinting. High affinity and selectivity was achieved by doping the prepolymerization mixture with a stoichiometric amount of methacrylamide-based bisphosphonate (BP) monomer. Taking advantage of the strong interaction of bisphosphonate with lysine/arginine residues on the surface of Trypsin, we have constructed a powerful polymeric sensor. The BP based sensor has the ability to recognize trypsin over other arginine-rich proteins, even in high ionic strength buffers with a sub-picomolar detection limit (pM). We believe that the combination of supramolecular chemistry, molecular imprinting and advanced instrumentation has a potential for future drug development and diagnostics that extends beyond biomolecular recognition.
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| 9. |
- Bernhardt, Paul V., et al.
(författare)
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Tailoring mixed-valence Co-III/Fe-II complexes for their potential use as sensitizers in dye sensitized solar cells
- 2008
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 32:4, s. 705-711
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Tidskriftsartikel (refereegranskat)abstract
- Dinuclear class II Co-III/Fe-II mixed-valence complexes of type [LnCo (III)(mu-NC) Fe-II(CN)(3)L-2](m-) (where L-n represents a pentadentate macrocycle and L-2 a bpy ligand or two cyanides) have electronic properties that make them possible sensitizers in DSSC ( dye sensitized solar cells). For this purpose the new complex Na-2[{trans-L14COOCo III( m-NC)} Fe II( CN) 5] has been prepared and characterized by the usual methods and its sensitizer properties compared with those of the already known [{trans-L14COOCo (III)(mu-NC)}Fe-II(CN)(5)](2-)(CN)(3)(bipy)(eq,ax)](ClO4). The complex [{trans-L14COOCo (III)(mu-NC)}Fe-II(CN)(5)](2-) has been designed for the actuation of an electron injection from the cobalt centre on MMCT, while the [{trans-L14COOCo (III)(mu-NC)}Fe-II(CN)(3)(bipy)](+) structure can produce a tuned injection from the iron centre via an MLCT electronic state, as described for similar systems. The characterization on solid oxide semiconductor supports has been carried out for these two complexes and the results have been compared with the behaviour observed in aqueous solution and in solvents of varying polarities. Their use in DSSC has been checked and, while a sensitizer response is observed for [{trans-L14COOCo (III)(mu-NC)}Fe-II(CN)(5)](2-), complex [{trans-L14COOCoIII(mu-NC)}Fe-II(CN)(3)(bipy)(eq,ax)](+) does not produce any electrical current on illumination. The low efficiency of the built DSSC can be easily related both with the very low value of the extinction coefficient of the MMCT band responsible for the electron injection, and with the small driving force for the reduction of the complex with the standard I-2/I-3 (-) system used after electron injection.
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| 10. |
- Bhuyan, Prabal Dev, et al.
(författare)
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Ultrathin nanowire PdX2 (X = P, As) : stability, electronic transport and thermoelectric properties
- 2020
-
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 44:36, s. 15617-15624
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Tidskriftsartikel (refereegranskat)abstract
- In the last few decades, the miniaturization of devices has been taking place and therefore the quest for new nanowires has become more significant. In the present study, we have investigated the geometry of new ultrathin nanowires (NWs) of PdP2 and PdAs2 that could be obtained experimentally. We have optimized the pentagonal structures of both the NWs and studied their dynamical stability using the phonon dispersion curve. The electronic band structure shows semiconducting behaviour of PdP2 NWs with a band gap of 380 meV and PdAs2 NWs with a band gap of 294 meV, with higher charge carrier mobility than that of their 2D counterparts. The NWs show a band gap of 840 meV and 740 meV for PdP2 and PdAs2, respectively, through hybrid potential calculations. The PdX2 structure shows a transition from semiconducting to semi-metallic behaviour at a compressive strain of 8% within a sustainable pressure of 0.2–0.3 GPa. A negative differential conductance (NDC) effect is observed in the current–voltage graph for both the NWs. The semi-metallic behaviour with an asymmetric density of states near the Fermi energy boosts the Seebeck co-efficient value and therefore the ZTe value is enhanced for both the nanowires. The strained PdP2 and PdAs2 NWs show ZTe values of 4.75 and 5.49, respectively. Our study stimulates the feasibility of both nanowires and thermoelectric applications for the conversion of waste heat into electricity.
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| 11. |
- Bondarchuk, Sergey V., et al.
(författare)
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Two isomeric solid carbon nitrides with 1:1 stoichiometry which exhibit strong mechanical anisotropy
- 2017
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Ingår i: New Journal of Chemistry. - : ROYAL SOC CHEMISTRY. - 1144-0546 .- 1369-9261. ; 41:21, s. 13140-13148
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Tidskriftsartikel (refereegranskat)abstract
- Two isomeric layered carbon nitride phases in a trigonal crystal system with 1:1 stoichiometry, NCCN and NCNC (space group P3m1), are studied using first principles calculations and quantum theory of atoms in molecules (QTAIM) analysis, where the latter phase is predicted for the first time. Comprehensive characterization of these materials is performed to determine their thermodynamic, elastic and spectral (vibrational, UV-vis and NMR) properties. High-throughput scheme for band structure calculations along with the accurate hybrid functional HSE06 provide the indirect band gaps of 3.142 eV (NCNC) and 5.021 eV (NCCN). Phonon dispersion calculations prove that the studied materials are dynamically stable at ambient pressure. The NCCN phase demonstrates a poor spectral pattern on infrared (IR) intensities and Raman activities, whereas the NCNC polymorph is expected to be effectively detectable by both spectral techniques. The UV-vis spectra of the studied phases display absorption bands between ca. 50-150 nm, which indicates that these isomers are transparent to visible light. Elastic constant calculations indicate strong anisotropy of their Young's moduli. In the [1 0 0] equivalent to [0 1 0] plane directions the modulus values are 914.6 GPa (NCNC) and 865.1 GPa (NCCN). In the [0 0 1] direction, which is perpendicular to the layer plane, the Young's moduli are much smaller and equal to 73.3 GPa and 58.4 GPa for NCNC and NCCN, respectively. The exfoliation energies are expected to be about 3 (NCNC) and 2 (NCCN) times higher than those of graphite.
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| 12. |
- Bouit, Pierre-Antoine, et al.
(författare)
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Dendron-decorated cyanine dyes for optical limiting applications in the range of telecommunication wavelengths
- 2009
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 33:5, s. 964-968
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Tidskriftsartikel (refereegranskat)abstract
- Cyanine dyes decorated with 2,2-bis(methylol) propionic acid (bis-MPA) based dendrons up to third generation were synthesized. Dendrons were attached to the chromophore using a "click chemistry'' reaction. Photophysical characterizations of these dyes show intense absorption and emission in the near-infrared (NIR), while nonlinear transmission experiments of the dendron-decorated chromophores indicate that properties in the IR of the parent dyes are conserved. This synthetic approach is a crucial preliminary step towards the preparation of solid functional materials for optical limiting (OL) applications in the IR.
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| 13. |
- Buzolin, C. N., et al.
(författare)
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In situ determination of dissolution kinetics of d-limonene in supercritical carbon dioxide by Raman spectroscopy
- 2017
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 41:22, s. 13929-13934
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Tidskriftsartikel (refereegranskat)abstract
- The study of solvation in pressurized systems requires in situ analysis. An optimal spectroscopic technique for such studies would enable the detection of any compound and have resolution enough to differentiate different compounds within a multicomponent mixture. Here we show for the first time that we can follow dissolution kinetics of a model compound, d-limonene, in supercritical carbon dioxide using in situ Raman spectroscopy. Dissolution rate constants were measured at different stirring speeds, temperatures (45 and 55 °C) and amounts of CO2, corresponding to pressures in the range of 8.4 to 17.0 MPa. Dissolution half-lives ranged from 3 min (at 45 °C and 8.4 MPa) up to more than 1 hour (at 55 °C 16.9 MPa). The results indicate that dissolution is mostly controlled by diffusion, while convection did not play a significant role. Dissolution rate constants showed a non-linear inverse relation with diffusivity, while temperature did not influence the dissolution rate constants significantly. Dissolution kinetics is revealed as a significant aspect to consider for the optimization of extraction and separation processes based on supercritical carbon dioxide. Overall, this study offers new insight into solvation phenomena in pressurized fluids.
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| 14. |
- Cano, A., et al.
(författare)
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Contribution to the coordination chemistry of transition metal nitroprussides : a cryo-XPS study
- 2019
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 43:12, s. 4835-4848
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Tidskriftsartikel (refereegranskat)abstract
- The series of coordination polymers under investigation was formed by the assembly of a pentacyanonitrosylferrate(ii) anionic block, [Fe(CN)(5)NO](2-), through monovalent and divalent transition metal ions, e.g. Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Ag+. For divalent ions, the resulting materials have a 3D porous framework with attractive features for applications in gas storage and separation, as electroactive solids, light-driven molecular magnets, and so on; in this study, we report the results obtained for a series of coordination polymers using the cryogenic X-ray photoelectron spectroscopy (cryo-XPS) data; comprehensive details regarding their coordination chemistries were obtained from the acquired spectra in addition to their comparison with the structural and spectroscopic information obtained from other techniques. The results discussed herein are original and contribute towards the understanding of the electronic structures and related properties for this family of coordination polymers. This series of solids was found to be highly susceptible to strong damage induced by X-ray beams throughout the conventional XPS experiment; therefore, the analysis was conducted under cryogenic conditions.
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| 15. |
- Chaignon, Frederique, et al.
(författare)
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Photoinduced electron transfer in ruthenium(II) trisbipyridine complexes connected to a naphthalenebisimide via an oligo(phenyleneethynylene) spacer
- 2009
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 33:2, s. 408-416
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Tidskriftsartikel (refereegranskat)abstract
- The preparation and the characterization of three new dyads composed of a ruthenium trisbipyridine complex linked to a naphthalene bisimide electron acceptor via a phenyleneethynylene spacer of different length (one or two units) are reported. The dyads also differ by the anchoring position of the spacer on the bipyridine, which is appended either at the 4-position or the 5-position. Cyclic voltammetry and the UV-Vis absorption spectroscopy suggested that the spacer linked at the 5-position ensures a longer pi-conjugation length but the electron transfer rates indicate a lower electronic coupling, than in 4-position. Photoinduced emission yields indicate a significant quenching of the MLCT excited-state of the ruthenium complex in these dyads. Except for the dyad linked in 5 position with one phenyleneethynylene unit, the transient absorption spectroscopy of all the other dyads evidences that the MLCT excited-state decays almost exclusively by electron transfer to form the charge-separated state Ru-III-NBI-. This state could not be observed, presumably because the subsequent recombination to the ground state was much faster than its formation. In the dyad linked in 5 position with only one phenyleneethynylene unit, at room temperature, the (MLCT)-M-3* state is in equilibrium with the (NBI)-N-3* state, and it also decays via electron transfer. The notable feature of these dyads is first the occurrence of a relatively long-range electron transfer reaction via a bis(phenylethynylene) linking unit anchored at the 5 position. Secondly, we show within these series of compounds that subtle variations in the structure of the dyads (length of the spacer and anchoring position on bipy) have a strong impact on the rates and in the mechanism of decay of the (MLCT)-M-3* state. The photophysical properties of the dyads can be explained in terms of energy proximity of different excited states and magnitude of the electronic coupling according to the anchoring position.
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| 16. |
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| 17. |
- Chajara, Khalil, et al.
(författare)
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The reagent-free, microwave-assisted purification of carbon nanotubes
- 2010
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 34:10, s. 2275-2280
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a microwave-assisted, reagent-free method for the efficient primary purification of MW and SW carbon nanotubes that is extremely fast compared to previously reported processes. The treatment dissociates and disperses non-nanotube carbon in an organic solvent to yield very pure carbon nanotubes within a few minutes of heating and a simple filtration, without the involvement of acidic/oxidative reagents. According to thermogravimetric analysis, Raman and IR spectroscopy, as well as scanning and transmission electron microscopy, the process yields pure nanotubes with a low degree of defects.
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| 18. |
- Chen, Huang, et al.
(författare)
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A portable micro glucose sensor based on copper-based nanocomposite structure
- 2019
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1369-9261 .- 1144-0546. ; 43:20, s. 7806-7813
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Tidskriftsartikel (refereegranskat)abstract
- Precisely detecting the concentration of glucose in the human body is an attractive way to prevent or treat diabetes. Portable glucose sensors with non-enzymatic catalytic materials have received great attention in recent years. Herein, a facile strategy for fabricating a high-performance electrochemical sensor is proposed. A non-enzymatic three-electrode integrated glucose sensor device based on CuO nano-coral arrays/nanoporous Cu (NCA/NPC) is designed and fabricated. The portable NCA/NPC glucose sensor device exhibits high catalytic activity for glucose. The great performance of the NCA/NPC glucose sensor device derives from the excellent conductivity of the NPC substrate and the high electrocatalytic activity of CuO nano-coral arrays. This device exhibits a high sensitivity of 1621 μA mM -1 cm -2 in the linear range of 0.0005-5.0 mM, low detection limit of 200 nM (S/N = 3), fast response time of 3 s, good anti-interference performance, excellent repeatability and considerable stability for glucose detection. This work will certainly provide an efficient structure and proper catalytic material choices for future non-enzymatic glucose sensors.
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| 19. |
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| 20. |
- Dayaker, G., et al.
(författare)
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Enantioselective deprotometalation of alkyl ferrocenecarboxylates using bimetallic bases
- 2021
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 45:48, s. 22579-22590
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Tidskriftsartikel (refereegranskat)abstract
- The enantioselective deprotometalation of alkyl ferrocenecarboxylates (FcCO(2)R) using mixed lithium-zinc or lithium-cadmium bases is described. By using FcCO(2)Me as the substrate, chiral lithium alkyl-amidozincates prepared from exo-(alpha R)- or endo-(alpha S)-N-(alpha-phenylethyl)bornylamine (H-exo-born-R or H-endo-born-S) were tested; the best results (27% yield and 62% ee in favor of the R-P enantiomer) were obtained by using Bu-2(endo-born-S)ZnLi in tetrahydrofuran (THF) at -30 degrees C before iodolysis. Due to the low compatibility of FcCO(2)Me with alkyl-containing lithium zincates, 1 : 1 mixtures of lithium and zinc amides were tested. Chiral (H-exo-born-R or H-endo-born-S) or/and achiral (lithium 2,2,6,6-tetramethylpiperidide or lithium diisopropylamide) secondary amines gave good results, the best (81% yield and 44% ee in favor of the R-P enantiomer) being obtained by using (endo-born-S)(3)ZnLi in THF at room temperature. Among other secondary amines also prepared and/or tested, commercial (S,S)-bis(alpha-phenylethyl)amine (H-PEA-S) proved promising. After optimization of the reaction conditions, the best enantioselectivity (26% yield and 80% ee in favor of the RP enantiomer) was observed by treating a THF solution of FcCO(2)Me and Zn(PEA-S)(2) with Li-PEA-S at -80 degrees C before iodolysis. That no reaction took place with cadmium instead of zinc suggests the formation of 'ate complexes upon treatment of Cd(PEA-S)(2) by Li-PEA-S while Zn(PEA-S)(2) and Li-PEA-S would rather work in tandem (Li-PEA-S as the base and Zn(PEA-S)(2) as the in situ trap for the formed ferrocenyllithium). While FcCO(2)Me, FcCO(2)tBu and FcCO(2)iPr could be converted into their racemic 2-iodinated derivatives with a yield of 84 to 87% by employing LiTMP (2 equiv.) in the presence of ZnCl2.TMEDA (1 equiv.) as an in situ trap, their enantioselective deprotometalation rather required Li-PEA-S together with Zn(PEA-S)(2) to produce the enantio-enriched derivatives with yields of 45-82% and 71% ee.
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| 21. |
- Deksnys, T., et al.
(författare)
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Synthesis and characterisation of a carbazole-based bipolar exciplex-forming compound for efficient and color-tunable OLEDs
- 2017
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Ingår i: New Journal of Chemistry. - : RSC Publishing. - 1144-0546 .- 1369-9261. ; 41:2, s. 559-568
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Tidskriftsartikel (refereegranskat)abstract
- A new ambipolar fluorophore, 3,6-di(4,4′-dimethoxydiphenylaminyl)-9-(1-naphthyl)carbazole, was synthesized and its physical properties were studied by differential scanning calorimetry, thermogravimetric analysis, UV-vis absorption, luminescence and photoelectron emission spectroscopy, cyclic voltammetry and a time of flight method. The latter technique indicates that the compound demonstrates bipolar semiconducting properties. Using the synthesized compound as an emissive material, a single-layer OLED with an electroluminescence spectrum containing a voltage-dependent electroplex emission band in the region of 550-650 nm was fabricated. Another OLED was fabricated with an additional electron transporting bathophenanthroline layer that forms a direct interface with the layer of 3,6-di(4,4′-dimethoxydiphenylaminyl)-9-(1-naphthyl)carbazole. A strong exciplex-type band in the electroluminescence spectrum of this OLED with an emission maximum at ca. 540 nm was observed. The electroluminescence spectra of both devices were found to be clearly dependent on the applied bias. This effect can be useful for the development of efficient and colour-tunable OLEDs.
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| 22. |
- Deshpande, Swapnil, et al.
(författare)
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Binding and optical characteristics of polycyclic aromatic hydrocarbons and their nitroderivatives adsorbed on the C3N monolayer
- 2022
-
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 46:5, s. 2245-2258
-
Tidskriftsartikel (refereegranskat)abstract
- Carbon-nitrogen based two dimensional frameworks have attracted significant attention due to their great potential for environmental applications. Among the g-CxNy family, the C3N monolayer (ML) is one of the promising candidates, which exhibits semiconducting behavior. The structural, electronic and optical properties of the polycyclic aromatic hydrocarbons (PAHs) and their nitroderivatives adsorbed on the C3N ML have been investigated using first principles calculations. We chose six representative molecules from the PAH family, benzene (B), anthracene (A), and benzo[a]pyrene (BaP), and their nitroderivatives, nitrobenzene (NB), 9-nitroanthracene (NA), and 6-nitro-benzo[a]pyrene (NBaP). These molecules are severely affecting human beings and aquatic systems. The optimal adsorption orientation of these molecules on the C3N ML is determined and the adsorption energies (E-ads) are calculated. The E-ads of these PAH molecules with C3N ML are found to be higher than that of graphene. The PAH molecules with the nitro group show higher E-ads as compared to that of molecules without the nitro group. Further, we have checked the implicit water solvation effect on the adsorption behavior of PAHs on the C3N ML. In a water solvent, E-ads further increases. The energy gap of the C3N ML is sensitive to the adsorption of these nitroderivatives of the PAH molecules, which implies the possibility of its use as a sensor. We have noticed an increase in the calculated work function upon the adsorption of PAH molecules which further explains the affinity of the C3N ML towards these molecules. The static dielectric constant epsilon(1)(0) and the refractive index (n(0)) of the pristine C3N ML are 4.24 and 2.06, respectively. Adsorption of B, A and BaP molecules on C3N does not have a significant impact on the values of epsilon(1)(0) and n(0). But adsorption of their nitroderivatives shows a notable increase in the values of epsilon(1)(0) and n(0). We believe that our results could trigger further theoretical and experimental work towards constructing highly sensitive nanosensors and optical devices to detect PAHs.
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| 23. |
- Deshpande, Swapnil, et al.
(författare)
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Tuning the electronic, magnetic, and sensing properties of a single atom embedded microporous C3N6 monolayer towards XO2 (X = C, N, S) gases
- 2022
-
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 46:28, s. 13752-13765
-
Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional frameworks have attracted significant attention due to their great potential in many applications. Among the g-CxNy family, C3N6 is one of the recently synthesized promising candidates, which exhibits semiconducting behavior. Motivated by its potential, we performed first-principles density functional theory (DFT) calculations to explore the structural, electronic, magnetic, and gas sensing properties of the C3N6 ML towards common pollutants, such as XO2 (X = C, N, and S). We found weak binding between the pristine C3N6 ML and XO2, which was not suitable for efficient gas capture. However, functionalization with a selected transition metal not only altered the electronic and magnetic properties but also improved the sensing behavior of TM-C3N6 (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn). We have analyzed the adsorption behavior, desorption time, and correlation matrix of TM embedded C3N6 towards XO2 (X = C, N, and S) gases. Electronic structures and magnetic moments of XO2 adsorbed TM-C3N6 depend on the atomic number of the embedded TM atom and the adsorbed gas molecules. We found that the adsorption energies of TM-C3N6 systems towards NO2 gas molecules are stronger in comparison to CO2 and SO2 gas molecules, which suggested a selective capture mechanism. Based on our findings, TM-C3N6 systems turned out to be promising adsorbent materials for environmentally toxic pollutants.
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| 24. |
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| 25. |
- Dinér, Peter, 1976, et al.
(författare)
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Short cut to 1,2,3-triazole-based p38 MAP kinase inhibitors via [3+2]-cycloaddition chemistry
- 2009
-
Ingår i: New J. Chem.. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 33:5, s. 1010-1016
-
Tidskriftsartikel (refereegranskat)abstract
- A series of 4,5-substituted 1,2,3-triazoles was synthesised via Cu(I)-catalysed azide–alkyne 1,3-dipolar [2+3]-cycloaddition reactions followed by a Suzuki coupling. The 1,2,3-triazoles were evaluated as inhibitors of the p38 MAP kinase, showing IC50 values in the high nanomolar range
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| 26. |
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| 27. |
- Dokhaee, Z., et al.
(författare)
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Investigation of the blends of chitosan and tragacanth as potential drug carriers for the delivery of ibuprofen in the intestine
- 2019
-
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 43:37, s. 14917-14927
-
Tidskriftsartikel (refereegranskat)abstract
- Natural polymers are reliable compounds in drug delivery systems (DDS). Herein, two series of safe and reliable polyelectrolyte hydrogels (PEHs) were prepared from two oppositely charged polysaccharides, namely tragacanth (TG) and chitosan (CS), and applied for the delivery of ibuprofen as a model drug. Considering the different interactions of CS and TG as a polycation and a polyanion, respectively, with the drug, herein, two series of PEHs were prepared, and their diversity in morphology and drug release ability were studied. The system provided a high percentage of drug loading efficiency (>90%) and was sensitive to the acidity of different media. The drug release pattern was favorable; the data showed that the slowest rate of drug release was obtained at pH = 1.2, followed by pH = 5.4, and fastest drug release occurred at a slightly basic pH (=7.4); the mechanism of drug release was studied using different kinetic models, where at pH = 1.2 and 7.4, the drug release curve best matched the zero order and the Hixson-Crowell model, and at pH = 5.4, the Weibull model represented the perfect agreement with the drug release patterns. The stability of the drug carrier was explored by fluorescence imaging. The cytotoxicity of the CS-I-T 30% and CS-T composites was evaluated towards the cultured MCF7 cells for 24 and 48 h, and no toxic effects were observed.
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| 28. |
- Elgland, Mathias, 1987-, et al.
(författare)
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beta-Configured clickable [F-18] FDGs as novel F-18-fluoroglycosylation tools for PET
- 2017
-
Ingår i: New Journal of Chemistry. - : ROYAL SOC CHEMISTRY. - 1144-0546 .- 1369-9261. ; 41:18, s. 10231-10236
-
Tidskriftsartikel (refereegranskat)abstract
- In oncology and neurology the F-18-radiolabeled glucose analogue 2-deoxy-2-[F-18]fluoro-D-glucose ([F-18]FDG) is by far the most commonly employed metabolic imaging agent for positron emission tomography (PET). Herein, we report a novel synthetic route to beta-configured mannopyranoside precursors and a chemoselective F-18-fluoroglycosylation method that employ two b-configured [F-18]FDG derivatives equipped with either a terminal azide or alkyne aglycon respectively, for use as a CuAAC clickable tool set for PET. The b-configured precursors provided the corresponding [F-18]FDGs in a radiochemical yield of 77-88%. Further, the clickability of these [F-18]FDGs was investigated by click coupling to the suitably functionalized Fmoc-protected amino acids, Fmoc-N-(propargyl)-glycine and Fmoc-3-azido-L-alanine, which provided the F-18-fluoroglycosylated amino acid conjugates in radiochemical yields of 75-83%. The F-18-fluoroglycosylated amino acids presented herein constitute a new and interesting class of metabolic PET radiotracers.
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| 29. |
- Erdélyi, Máté, et al.
(författare)
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Insight into beta-hairpin stability : a structural and thermodynamic study of diastereomeric beta-hairpin mimetics
- 2002
-
Ingår i: New Journal of Chemistry. - 1144-0546 .- 1369-9261. ; 26, s. 834-843:26, s. 834-
-
Tidskriftsartikel (refereegranskat)abstract
- Two diastereomers of a model β-hairpin peptide mimetic were synthesized and studied with a combination of experimental (NMR, X-ray, CD, MS, IR) and computational methods (Monte Carlo/molecular mechanics calculations). The secondary structure-stabilizing effects of hydrophobic interactions and hydrogen bonding were investigated. Comparison of the extent of folded hairpin population in non-competitive, polar aprotic, and polar protic solvents illustrates the critical role of intramolecular hydrogen bonding on hairpin stability. Investigation of 1H NMR melting curves of the diastereomeric compounds in a variety of solvents allowed an evaluation of the role of hydrophobic effects on secondary structure stabilization to be made.
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| 30. |
- Erdelyi, Mate, 1975, et al.
(författare)
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Insight into β -hairpin stability: a structural and thermodynamic study of diastereomeric β-hairpin mimetics
- 2002
-
Ingår i: New Journal of Chemistry. - 1369-9261 .- 1144-0546. ; 26, s. 834-843
-
Tidskriftsartikel (refereegranskat)abstract
- Two diastereomers of a model β-hairpin peptide mimetic were synthesized and studied with a combination of experimental (NMR, X-ray, CD, MS, IR) and computational methods (Monte Carlo/molecular mechanics calculations). The secondary structure-stabilizing effects of hydrophobic interactions and hydrogen bonding were investigated. Comparison of the extent of folded hairpin population in non-competitive, polar aprotic, and polar protic solvents illustrates the critical role of intramolecular hydrogen bonding on hairpin stability. Investigation of 1H NMR melting curves of the diastereomeric compounds in a variety of solvents allowed an evaluation of the role of hydrophobic effects on secondary structure stabilization to be made.
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| 31. |
- Ertürk, Gizem, et al.
(författare)
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Bisphosphonate ligand mediated ultrasensitive capacitive protein sensor : complementary match of supramolecular and dynamic chemistry
- 2018
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 43:2, s. 847-852
-
Tidskriftsartikel (refereegranskat)abstract
- Modern healthcare demands rapid and accurate detection of proteins/enzymes at the ultratrace level. Herein we present a molecularly imprinted capacitive sensor for trypsin, developed by microcontact imprinting. High affinity and selectivity was achieved by doping the prepolymerization mixture with a stoichiometric amount of methacrylamide-based bisphosphonate (BP) monomer. Taking advantage of the specific interaction between bisphosphonate binding monomers and lysine/arginine residues on the surface of trypsin, we have constructed a powerful polymeric sensor. The BP based sensor has the ability to recognize trypsin over other arginine-rich proteins, even in high ionic strength buffers with a sub-picomolar detection limit (pM). We believe that the combination of supramolecular chemistry, molecular imprinting and advanced instrumentation has a potential for future drug development and diagnostics that extends beyond biomolecular recognition.
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| 32. |
- Fagerland, Jenny, et al.
(författare)
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Modulating the thermal properties of poly(hydroxybutyrate) by the copolymerization of rac-beta-butyrolactone with lactide
- 2016
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 40:9, s. 7671-7679
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Tidskriftsartikel (refereegranskat)abstract
- Biobased poly(hydroxybutyrate) is produced by microorganisms under controlled conditions. It is a linear, high molecular weight, fully isotactic and highly crystalline polymer. However, it has poor mechanical and thermal properties. We have modulated the thermal properties of this material by ring-opening co-polymerization of rac-beta-butyrolactone (BL) with lactide (LA) in the presence of salan-based yttrium and aluminum catalysts. The prepared poly(hydroxybutyrate-co-lactide) copolymers were characterized by proton and carbon nuclear magnetic resonance (H-1 and C-13 NMR), size exclusion chromatography (SEC) and differential scanning calorimetry (DSC) analyses. The salan-yttrium compound was a more effective catalyst compared to the aluminum compound, affording high molecular weight copolymers with higher monomer conversion and a monomodal distribution of the molecular weights. The kinetic experiments showed a higher rate of polymerization for the LA with respect to the BL. The copolymers were amorphous and DSC showed unique transition temperatures for all of the samples. The formation of a gradient copolymer is proposed.
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| 33. |
- Foreman, Mark, 1973, et al.
(författare)
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Activity coefficients in deep eutectic solvents: Implications for the solvent extraction of metals
- 2018
-
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1369-9261 .- 1144-0546. ; 42:3, s. 2006-2012
-
Tidskriftsartikel (refereegranskat)abstract
- An understanding of the effects of the water content on the solvent extraction of metals from the deep eutetic formed from choline chloride and lactic acid has been obtained. This change can be rationalised as being due to a change in the activity coefficient of chloride in the deep eutetic.
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| 34. |
- George, Sumod, et al.
(författare)
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Crystal engineering of neutral N-arylpyrimidinones and their HCl and HNO3 adducts with a C-HO supramolecular synton : Implications for non-linear optics
- 2001
-
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 25:12, s. 1520-1527
-
Tidskriftsartikel (refereegranskat)abstract
- In a previous crystallographic study of some N-arylpyrimidinones 1, we noted that: (1) C-HO hydrogen bonds connect molecules in a linear array; (2) the charge transfer axis of the chromophore is aligned with the main symmetry operator of point groups 2 or m at ca. 57°, a value that is close to the ideal angle of 54.74°; (3) the methyl and chloro derivatives are isostructural. In this paper, we report the characterisation of chloride and nitrate salt adducts of 1 by X-ray diffraction and the analysis of their packing motifs. Recurrence of the same C-HO supramolecular synthon in three neutral and five HCl and HNO3 adducts of 1 signifies the robustness of this weak hydrogen bond. The occurrence of a mirror plane m in a family of eight crystal structures (four Pnma, two P21/m, one Pbcm, and one Pmn21) is unusual because this symmetry operation is generally avoided due to close packing considerations. Ab initio calculations show that the bisected phenyl conformation present in these crystal structures is the most stable conformation of the pyrimidinone molecule. The presence of aryl and pyrimidinone chromophores in 1, the correct alignment of the aromatic ring in the crystal and the occurrence of 2D polar layers in some crystal structures are favourable factors for non-linear optical applications. However, a strategy for the crystallisation of these achiral molecules in non-centrosymmetric space groups is yet to be achieved. This crystal engineering study simplifies the challenge of complete 3D structural control into a modular 2D+1D problem
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| 35. |
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| 36. |
- Ghazzali, Mohamed I D M, 1974, et al.
(författare)
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Syntheses, crystal structures, optical limiting properties, and DFT calculations of three thiophene-2-aldazine Schiff base derivatives
- 2007
-
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1369-9261 .- 1144-0546. ; 31:10, s. 1777-1784
-
Tidskriftsartikel (refereegranskat)abstract
- The syntheses, characterizations and structural determinations of N,N'-bis(thiophenyl-2-methylene)hydrazine 1, N,N'-bis(4-bromothiophenyl-2-methylene)hydrazine 2 and N,N'-bis(5-bromothiophenyl-2-methylene)hydrazine 3 are presented. The materials show third-ordernonlinear behaviour with transmissions of 20, 22 and 18 μJ for an input energy of 150 μJ. The4- and 5-bromothiophenic structures show Br...Br interactions of 3.562 and 3.626 Å, respectively.Analysis of bromine containing aromatic compounds in the Cambridge CrystallographicDatabase (CSD) showed the expected angle dependences of the Br...Br interactions dividing theseinto ‘‘type I’’ and ‘‘type II’’. A semi-quantitative agreement was found between the CSD data anda model derived form calculated electrostatic potentials.
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| 37. |
- Girgis, Adel S., et al.
(författare)
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Synthesis and DFT studies of an antitumor active spiro-oxindole
- 2015
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 39:10, s. 8017-8027
-
Tidskriftsartikel (refereegranskat)abstract
- An anti-oncological active spiro-oxindole 7 was synthesized regioselectively via a [3+2]-cycloaddition reaction of azomethine ylide to exocyclic olefinic linkage of 4-piperidone 6, exhibiting properties against diverse tumor cell lines including leukemia, melanoma and cancers of the lung, colon, brain, ovary, breast, prostate, and kidney. Compound 7 crystallizes in the monoclinic system and P21/c space group with four molecules in the unit cell. The structure was also studied by AM1, PM3 and DFT techniques. DFT studies support the stereochemical selectivity of the reaction and determine the molecular electrostatic potential and frontier molecular orbitals.
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| 38. |
- Gong, Zheng, et al.
(författare)
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A targetable fluorescent probe for detecting mitochondrial viscosity in live cells by using fluorescence lifetime imaging
- 2024
-
Ingår i: New Journal of Chemistry. - : ROYAL SOC CHEMISTRY. - 1144-0546 .- 1369-9261.
-
Tidskriftsartikel (refereegranskat)abstract
- Intracellular viscosity plays an important role in regulating cellular morphology and physiology and is closely related to a host of diseases. Especially, the changes in mitochondrial viscosity will cause some common diseases such as hyperlipidemia, Alzheimer's disease and cancer. In this work, we report the design of a red-emissive molecular rotor for the detection of mitochondrial viscosity in live cells. The probe showed fascinating performance, such as specific targeting to mitochondria, high sensitivity to viscosity, and rapid fluorescence response, especially the dual response mode of fluorescence intensity and fluorescence lifetime. By using this probe, we realized monitoring of the mitochondrial viscosity variations in live cells under different physiological processes. Our study offers an opportunity to discover potential tools for mitochondria-related physiology and pathology investigation. A D-pi-A typed fluorescence lifetime probe for sensitively detecting viscosity has been designed and synthesized. BSOH has been successfully applied to real-time monitoring mitochondrial viscosity in live cells by fluorescence lifetime imaging.
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| 39. |
- Gromov, SP, et al.
(författare)
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Novel supramolecular charge-transfer systems based on bis(18-crown-6)stilbene and viologen analogues bearing two ammonioalkyl groups
- 2005
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Ingår i: NEW JOURNAL OF CHEMISTRY. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 29:7, s. 881-94
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Tidskriftsartikel (refereegranskat)abstract
- A series of new viologen analogues bearing two ammonioalkyl groups (2-4) were synthesized in order to study their complexation with bis(18-crown-6)stilbene (1b). Electronic spectroscopy and H-1 NMR measurements show that in acetonitrile, bis( crown) stilbene 1b forms highly stable 1 : 1 and 2 : 1 charge-transfer (CT) complexes with pi-acceptors 2-4 owing to host-guest bonding. The influence of geometric and electronic factors on the complex formation constants are discussed. The structures of the supramolecular CT complexes are analyzed on the basis of H-1 and C-13 NMR data obtained in solution and in the solid state. X-Ray diffraction data for 1b and for model tetramethoxystilbene are also reported.
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| 40. |
- Gustafsson, Björn, 1970, et al.
(författare)
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Copper(II) is harder than copper(I): a novel mixed-valence example from alkoxide chemistry
- 2003
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 27:3, s. 459-461
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Tidskriftsartikel (refereegranskat)abstract
- Partial oxidation or disproportionation of tetrameric 2-allyl-6-methylphenoxocopper( I) leads to the formation of a novel trinuclear mixed-valence Cu(I) / Cu(II) alkoxide: [Cu-3 {OC6H3 (CH3) [CH2C(H) = CH2]}(4)], in which the central copper( II) atom is coordinated in a distorted square-planar configuration by four oxide ligands, whereas the peripheral copper( I) centres are each bonded to two C = C linkages and to two oxide ligands in a tetrahedral arrangement.
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| 41. |
- Haaima, G., et al.
(författare)
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Peptide nucleic acids (PNA) derived from N-(N-methylaminoethyl)glycine. Synthesis, hybridization and structural properties
- 1999
-
Ingår i: New Journal of Chemistry. - 1369-9261 .- 1144-0546. ; 23:8, s. 833-840
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Tidskriftsartikel (refereegranskat)abstract
- Backbone N-methylated peptide nucleic acids (PNAs) containing the four nucleobases adenine, cytosine, guanine and thymine were synthesized via solid phase peptide oligomerization. The oligomers bind to their complementary target with a thermal stability that is 1.5-4.5 degrees C lower per "N-methyl nucleobase unit" [dependent on the number and position(s) of the N-methyl] than that of unmodified PNA. However, even fully N-methyl modified PNAs bind as efficiently to DNA or RNA targets as DNA itself. Furthermore, the hybridization efficiency per N-methyl unit in a PNA decreased with increasing N-methyl content, and the effect was more pronounced when the N-methyl backbone units are present in the Hoogsteen versus the Watson-Crick strand in (PNA)(2)-DNA triplexes. Interestingly, CD spectral analyses indicate that 30% (3 out of ten) substitution with N-methyl nucleobases did not alter the structure of PNA-DNA (or RNA) duplexes or (PNA)(2)-DNA triplexes, and likewise CD spectroscopy and X-ray crystallography showed no major structural differences between N-methylated (30%) and unmodified PNA-PNA duplexes. However, PNA-DNA duplexes as well as triplexes adopted a different conformation when formed with all-Ai-methyl PNAs.
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| 42. |
- Harnes, J., et al.
(författare)
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The structure of mixed methanol/chloroform clusters from core-level photoelectron spectroscopy and modeling
- 2011
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 35:11, s. 2564-2572
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Tidskriftsartikel (refereegranskat)abstract
- Mixed neutral molecular clusters have been produced by co-expansion of chloroform and methanol and characterized by carbon 1s photoelectron spectroscopy and theoretical modeling. The produced clusters are in the range 50-150 molecules and the clusters are not homogeneously mixed: chloroform is enriched in the bulk and methanol is found on or close to the surface. This is based on evidence from photoelectron depth profiling and molecular dynamics simulations of mixed clusters. The simulations suggest that methanol forms cyclic or linear oligomers in the surface layers of the mixed clusters. From thermodynamic models, the enrichment of methanol on the cluster surface can be rationalized from the difference in surface tension between the two pure components, which is connected to the qualitative differences in the respective bonding patterns.
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| 43. |
- Héraly, Frédéric, 1995-, et al.
(författare)
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Capacitive CO2 sensor made of aminated cellulose nanofibrils : development and optimization
- 2024
-
Ingår i: New Journal of Chemistry. - 1144-0546 .- 1369-9261. ; 48:14, s. 6064-6070
-
Tidskriftsartikel (refereegranskat)abstract
- CO2 sensors are very important; however, their performance is limited by stability and selectivity. This study unveils a capacitive CO2 sensor with a dielectric layer comprised of amine-functionalized cellulose nanofibril (CNF) foam, significantly enhanced by the addition of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The core innovation of this research lies in the strategic use of CNF-based foam, which leads to a substantial increase in sensor capacitance, setting a new standard in CO2 monitoring technologies. The sensor showcases exceptional performance under ambient conditions, with marked improvements in sensitivity towards CO2. The advancements are attributed to the chemisorption properties of the aminated CNFs combined with the DBU enhancement, facilitating more effective CO2 capture. By integrating these materials, we present a sensor that opens new avenues for environmental monitoring, healthcare diagnostics, and industrial safety, establishing a new benchmark for capacitive CO2 sensors in efficiency and environmental sustainability.
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| 44. |
- Jadhav, S, et al.
(författare)
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Studies on colloidal stability of PVP-coated LSMO nanoparticles for magnetic fluid hyperthermia
- 2013
-
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 37, s. 3121-3130
-
Tidskriftsartikel (refereegranskat)abstract
- La0.7Sr0.3MnO3 (LSMO) nanoparticles with a size of ∼23 nm have been prepared by a combustion method and functionalized with polyvinylpyrrolidone (PVP) for their possible application in magnetic fluid hyperthermia (MFH). Uncoated and PVP-coated samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy and vibrating sample magnetometer studies. Magnetic measurements of both coated and uncoated particles reveal the superparamagnetic nature at room temperature. Colloidal stability has been measured in terms of zeta potential. The resulting PVP-coated particles form a stable suspension in phosphate buffer saline (PBS) and double distilled water (DDW) and possess a narrow hydrodynamic size distribution. The induction heating studies of these nanoparticles at different alternating magnetic fields (167.6, 251.4 and 335.2 Oe) were carried out by dispersing nanoparticles in DDW and PBS. These PVP-coated LSMO NPs exhibit a higher specific absorption rate in PBS than in DDW. The results suggest that combustion-synthesized LSMO nanoparticles coated with PVP can be used as potential heating agents in MFH.
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| 45. |
- Jarenmark, Martin, et al.
(författare)
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A monocarboxylate-bridged diiron(III) mu-oxido complex that catalyzes alkane oxidation by hydrogen peroxide
- 2010
-
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1369-9261 .- 1144-0546. ; 34:10, s. 2118-2121
-
Tidskriftsartikel (refereegranskat)abstract
- Reaction of the ligand 2-(N-isopropyl-N-{(2-pyridyl)methyl}aminomethyl)- 6-(N-(carboxymethyl)-N-((2-pyridyl)-methyl) aminomethyl)- 4-methylphenol (H2IPCPMP) with two equivalents of Fe(ClO4)(2) and two equivalents of sodium pivalate in air leads to the formation of the mu-oxido, mu-carboxylato-bridged diiron complex [{Fe(H-IPCPMP)}(2)(mu-O)(Piv)]ClO4 (1) (Piv = pivalate). Complex 1 is capable of catalysing the oxidation of cyclohexane or 1,2-cis-dimethylcyclohexane by hydrogen peroxide, leading to the formation of the corresponding cyclohexanone and cyclohexanol, as well as a small amount of cyclohexyl hydroperoxide.
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| 46. |
- Javed, Iqbal, et al.
(författare)
-
Photophysical and electrochemical properties and temperature dependent geometrical isomerism in alkyl quinacridonediimines
- 2014
-
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 38:2, s. 752-761
-
Tidskriftsartikel (refereegranskat)abstract
- Quinacridone diimines 1-10 were synthesized by the condensation of anilines with alkyl substituted quinacridones (QA). Photophysical and electrochemical properties of the compounds were investigated. Unconventional behavior of absorption spectra suggested a decrease in pi(-)conjugation within the QA skeleton as well as lack of extended pi(-)conjugation between the QA skeleton and the N-phenyl rings. A computational study of compounds 1-10, a variable temperature H-1 NMR study of compounds 2, 7 and 10 (for instance), and single crystal X-ray analysis of 2, 3, 6, 7, 8 and 10 indicated that the anomalous behavior is due to the buckled, non-planar structure of the quinacridones. Moreover the molecules existed in two interconvertible geometric isomeric forms at different temperatures. Molecular orbital calculations were performed at B3LYP/6-31+G(d), B3PW91/6-31G(d) and PBEPBE/6-31G(d) levels of theory at B3PW91/6-31G(d) optimized structures for both isomers of all compounds (1-10); the results obtained are in close agreement with the experimentally determined values.
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| 47. |
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| 48. |
- Karaush-Karmazin, Nataliya N., et al.
(författare)
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Impact of heteroatoms (S, Se, and Te) on the aromaticity of heterocirculenes
- 2019
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Ingår i: New Journal of Chemistry. - : ROYAL SOC CHEMISTRY. - 1144-0546 .- 1369-9261. ; 43:30, s. 12178-12190
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Tidskriftsartikel (refereegranskat)abstract
- A series of thia[7]circulenes and novel Se-, Te-, S/Te-, and Se/Te-substituted [8]circulenes have been studied by calculations of nucleus-independent chemical shift indices and gauge including magnetically induced currents to interpret the impact of heteroatoms on the aromatic properties of these polyheterocyclic species. The calculations indicate that all the studied hetero[7]circulenes and hetero[8]circulenes consist of two concentric subsystems: an inner seven- or eight-membered core is antiaromatic because of the existence of a paratropic ring current, and an outer system of benzene and hetarene rings that exhibit aromatic behaviour due to the circulation of diatropic ring currents. Thus, most of the hetero[7]circulenes can be considered as slightly antiaromatic because of the slight domination of the paratropic ring currents over the diatropic ones, whereas hetero[8]circulenes represent aromatic species due to the prevailing contribution of the diatropic currents. The antiaromaticity gradually increases with more scattered arrangements of the thiophene and benzene rings in each series of di-, tri-, tetra-, and pentathia[7]circulenes because of the reduced conjugation effect between the neighboring thiophene and benzene rings. Loss of planarity with increased strain leads to an increased antiaromatic character of the lower representatives of the thia[n]circulenes, whereas higher thia[n]circulenes demonstrate a more pronounced aromatic nature because of the small deviation from planarity. The ring current topology is found to be quite insensitive to the heteroatom type, number of hetarene rings and the size of the inner ring; this clearly manifests the special electronic structure of hetero[n]circulenes containing two concentric cyclic subsystems.
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| 49. |
- Karaush-Karmazin, Nataliya N., et al.
(författare)
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Structure, stability and electronic properties of one-dimensional tetrathia- and tetraselena[8]circulene-based materials : a comparative DFT study
- 2020
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 44:17, s. 6872-6882
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Tidskriftsartikel (refereegranskat)abstract
- Conjugated polymers gain much attention due to the promising applications in organic electronic device technology. In this work, we theoretically study the structures and electronic properties of a novel class of nanostructures, namely one-dimensional tetrathia[8]circulenes (TTC) and tetraselena[8]circulenes (TSC) predicted to be promising semiconducting soft materials. It is found that all nanoribbons are thermodynamically stable and that their electronic properties depend significantly on the type of fusing between the monomers. In particular, the band gap tends to decrease while moving from the directly fused TTC/TSC ribbons to the structures coupled via a benzene-core linker and then to the ribbons fused through a four-membered ring. Therefore, both coupling type and length of oligomers allow one to manipulate the electronic and optical properties of the studied ribbons. The band structure calculations of infinite nanoribbons reveal direct band gaps that decrease from 2.28 to 2.14 eV for the TTC ribbons of the first and second fusion types. The TSC structures demonstrate the same trend exhibiting band gap narrowing from 2.41 (type I) up to 2.11 eV (type II). The type III ribbons possess a lack of periodicity due to the close-lying energy minima for the possible twisting configurations of TTC and TSC moieties relative to the linking four-membered ring.
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| 50. |
- Karaush, Nataliya N., et al.
(författare)
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A theoretical study of new representatives of closed- and open-circle benzofuran and benzocyclopentadienone oligomers
- 2018
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 42:14, s. 11493-11505
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Tidskriftsartikel (refereegranskat)abstract
- Owing to their potential use as materials for strong optical rotation, circular dichroism and circularly polarized luminescence, the structure and energetic stability of novel closed- and open-circle benzofuran and benzocyclopentadienone oligomers have been studied computationally using the DFT method. It is found that an extension of the macrocycle size (n = 10-30) for the closed-circle species leads to a gradual transformation of their structure from saddle- to helical- and then to a wing-like shape. At the same time, the smaller closed-circle representatives with n = 4 and 6 exhibit a bowl-shaped structure due to the high energy strain of their molecular structures. Application of the NICS (nucleus-independent chemical shift) criterion to the here studied open-circle benzofuran and benzocyclopentadienone species with planar linear, planar fan-shape and helical molecular topology indicates that for the planar benzofuran series the inner benzene ring is more aromatic than the outer hexagons, while the aromaticity of the outer and inner furan rings is insensitive to the molecular size variations. The replacement of the aromatic furan rings by antiaromatic cyclopentadienone fragments for the planar linear species leads to a decrease of aromaticity of the benzene rings from the edge to the center of the benzocyclopentadienone chain. On the other hand, for the planar fan-shape benzocyclopentadienone series a zigzag trend in the NICS values is observed for the benzene rings. Loss of planarity only slightly affects the aromaticity of the helical open-circle benzofuran and benzocyclopentadienone oligomers. We propose that an increase of the NICS indices for the outer and inner rings of the macromolecular helical species is due to the magnetic couplings between the superimposed benzene and furan/cyclopentadienone rings.
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