Viologens (<i>N,N'</i>-dimethyl-4,4-bipyridinium) are advanced functional materials, found important applications in electrochromic devices, molecular machines, organic batteries, and carbohydrate oxid...Viologens (<i>N,N'</i>-dimethyl-4,4-bipyridinium) are advanced functional materials, found important applications in electrochromic devices, molecular machines, organic batteries, and carbohydrate oxidation catalysts in alkaline fuel. In this article, we investigated the design, synthesis and photophysical properties of <i>N,N'</i>-dimethyl-2,5-Bis(pyridinium)oxadiazole <b>4</b> and its precursor 2,5- Bis(pyridine)oxadiazole<b> 2</b>. The crystal structure and photophysical properties of viologen <b>4</b> and precursor <b>2</b> have been determined. The viologen molecule <b>4</b> crystallized in monoclinic form, space group <i>P</i>2<sub>1</sub>/<i>n</i> with four molecules in unit cell. Precursor molecule <b>2</b> also crystalized in monoclinic form, space group <i>C</i>2/<i>c</i> with four molecules in unit cell. From X-rd data, we found three cations in the molecular structure of viologen molecule <b>4</b>, which is unusual in viologens. In the three-dimensional molecular packing diagram of molecule <b>4</b>, the three cations and iodate anions are stabilized by C···C, C···I, N···I, N···H, H···I, N—H···I and C—H···I. The dihedral angle between planes having oxadiazole and two benzene rings are 5°and 8°, suggesting the molecule <b>4</b> is a slightly strained one. The molecular structure of precursor molecule <b>2</b> stabilized by C···C and N···H short contacts between the molecules. The molecule <b>4</b> displayed strong absorbance at 315 nm and emissions between 390 - 410 nm.展开更多
Zinc complexes of Schiff base ligands exhibit interesting properties which could be exploited for potential applications as catalysts and models for biochemical syste<span style="font-family:Verdana;">...Zinc complexes of Schiff base ligands exhibit interesting properties which could be exploited for potential applications as catalysts and models for biochemical syste<span style="font-family:Verdana;">ms. In this study, we report of the synthesis of a new zinc Schiff base complex, bis</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">(N’-(pyridine-3-carboxaldehyde) isonicotinoylhydrazone) zinc(II), which </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">has been characterized by physico-chemical methods. The X-ray single crystal structure of the complex has also been determined. The Schiff base ligand is bonded</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> to the metal in a monodentate manner, coordinating through the pyridine N-atom, as shown from spectral studies. The crystal structure shows the zinc atom bonded to two Schiff base</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> and four aqua ligands, with each Schiff base ligand coordinating through its pyridine N-atom forming a distorted octahedral ZnN</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">O</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> complex. Two water molecules and two nitrate ions found in the crystal structure link the different monomers through hydrogen bonding to form a layered supramolecular structure.</span></span></span></span>展开更多
文摘Viologens (<i>N,N'</i>-dimethyl-4,4-bipyridinium) are advanced functional materials, found important applications in electrochromic devices, molecular machines, organic batteries, and carbohydrate oxidation catalysts in alkaline fuel. In this article, we investigated the design, synthesis and photophysical properties of <i>N,N'</i>-dimethyl-2,5-Bis(pyridinium)oxadiazole <b>4</b> and its precursor 2,5- Bis(pyridine)oxadiazole<b> 2</b>. The crystal structure and photophysical properties of viologen <b>4</b> and precursor <b>2</b> have been determined. The viologen molecule <b>4</b> crystallized in monoclinic form, space group <i>P</i>2<sub>1</sub>/<i>n</i> with four molecules in unit cell. Precursor molecule <b>2</b> also crystalized in monoclinic form, space group <i>C</i>2/<i>c</i> with four molecules in unit cell. From X-rd data, we found three cations in the molecular structure of viologen molecule <b>4</b>, which is unusual in viologens. In the three-dimensional molecular packing diagram of molecule <b>4</b>, the three cations and iodate anions are stabilized by C···C, C···I, N···I, N···H, H···I, N—H···I and C—H···I. The dihedral angle between planes having oxadiazole and two benzene rings are 5°and 8°, suggesting the molecule <b>4</b> is a slightly strained one. The molecular structure of precursor molecule <b>2</b> stabilized by C···C and N···H short contacts between the molecules. The molecule <b>4</b> displayed strong absorbance at 315 nm and emissions between 390 - 410 nm.
文摘Zinc complexes of Schiff base ligands exhibit interesting properties which could be exploited for potential applications as catalysts and models for biochemical syste<span style="font-family:Verdana;">ms. In this study, we report of the synthesis of a new zinc Schiff base complex, bis</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">(N’-(pyridine-3-carboxaldehyde) isonicotinoylhydrazone) zinc(II), which </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">has been characterized by physico-chemical methods. The X-ray single crystal structure of the complex has also been determined. The Schiff base ligand is bonded</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> to the metal in a monodentate manner, coordinating through the pyridine N-atom, as shown from spectral studies. The crystal structure shows the zinc atom bonded to two Schiff base</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> and four aqua ligands, with each Schiff base ligand coordinating through its pyridine N-atom forming a distorted octahedral ZnN</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">O</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> complex. Two water molecules and two nitrate ions found in the crystal structure link the different monomers through hydrogen bonding to form a layered supramolecular structure.</span></span></span></span>
