کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1411678 | 1501875 | 2008 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
X-ray crystallographic and molecular sensing properties of [ZnCl2(κ2-N,Nâ²-dpknph)] (dpknph = di-2-pyridyl ketone-p-nitrophenyl hydrazone)
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: X-ray crystallographic and molecular sensing properties of [ZnCl2(κ2-N,Nâ²-dpknph)] (dpknph = di-2-pyridyl ketone-p-nitrophenyl hydrazone) X-ray crystallographic and molecular sensing properties of [ZnCl2(κ2-N,Nâ²-dpknph)] (dpknph = di-2-pyridyl ketone-p-nitrophenyl hydrazone)](/preview/png/1411678.png)
چکیده انگلیسی
When ZnCl2 was allowed to react with di-2-pyridyl ketone p-nitrophenylhydrazone (dpknph) in acetonitrile under reflux, [ZnCl2(κ2-N,Nâ²-dpknph)] was isolated in good yield. The formulation of the isolated product was established from the results of its elemental analysis and a number of spectroscopic measurements. Single crystal X-ray structural analysis done on [ZnCl2(κ2-N,Nâ²-dpknph)].dmf isolated from a dmf solution of [ZnCl2(κ2-N,Nâ²-dpknph)] shows the pyridine N,Nâ²-bidentate binding of dpknph and revealed a serpentine polymeric network of [ZnCl2(κ2-N,Nâ²-dpknph)].dmf units locked via a web of hydrogen bonds. 1H NMR spectra of [ZnCl2(κ2-N,Nâ²-dpknph)] measured in d6-dmso, d7-dmf and d6-acetone confirmed the coordination of dpknph and showed partial exchange of the amide proton with solvent protons in d6-acetone and that [ZnCl2(κ2-N,Nâ²-dpknph)] is stable in dmso and dmf. 1H NMR variable temperature studies confirmed the stability of [ZnCl2(κ2-N,Nâ²-dpknph)] in d6-dmso and d7-dmf and showed the presence of temperature-dependent shielded protons due to hydrogen bonding. The electronic absorption spectra of [ZnCl2(κ2-N,Nâ²-dpknph)] in non-aqueous media show a single solvent-dependent intra-ligand-charge transfer (ILCT) transition of the donor-acceptor type between 300 and 700 nm. Thermo-optical measurements in protophilic solvent (dmso or dmf) between 303.15 and 353.15 K show the stability of [ZnCl2(κ2-N,Nâ²-dpknph)] at those temperatures. In the presence of a base, a new ILCT peak appeared at 580 ± 2 nm in dmso, and the addition of an acid to a mixture of [ZnCl2(κ2-N,Nâ²-dpknph)] and a base showed the disappearance of the peak at 580 ± 2 nm and reappearance of the peak due to [ZnCl2(κ2-N,Nâ²-dpknph)]. These results established reversible inter-conversion between [ZnCl2(κ2-N,Nâ²-dpknph)] and its conjugate base, and allow for the use of [ZnCl2(κ2-N,Nâ²-dpknph)] in dmso to measure and detect substrates in concentrations as low as 1.00 Ã 10â5 M. Thermo-optical measurements on a mixture of [ZnCl2(κ2-N,Nâ²-dpknph)] and NaBH4 in dmso confirmed the reversible inter-conversion between [ZnCl2(κ2-N,Nâ²-dpknph)] and its conjugate base, and gave changes in enthalpy of 43.32 kJ/mol and entropy of 138.87 JKâ1 molâ1 at 298.15 K.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure - Volume 889, Issues 1â3, 29 October 2008, Pages 35-44
Journal: Journal of Molecular Structure - Volume 889, Issues 1â3, 29 October 2008, Pages 35-44
نویسندگان
Mohammed Bakir, Rebecca R. Conry, Orville Green,