.1,3,4 - Oxadiazole Derivatives Complex Synthesis, Structure And Performance

In this paper, 5-pyridyl-2-mercapto-1,3,4-oxadiazole was synthesized accordingto the existing literature with isonicotinyl hydrazide as a raw material firstly, and thenin the alkaline condition, two complex unsymmetry ligands (L¹,L²) were synthesizedutilizing 5-pyridyl-2-mercapto-1,3,4-oxadiazole and benzyl chloride via nucleophilicsubstitution reaction. Ligand L¹ is2-(2-pyridylmethylthio)-5-(4-pyridyl)-1,3,4-oxadiazole and ligand L² is2-(3-pyridylmethylthio)-5-(4-pyridyl)-1,3,4-oxadiazole. NaN(CN)₂ and KSCN havebeen selected as bridging ligands, we have synthesized five transition metalcomplexes The complexes including [Zn(L¹)₂(NCS)₂] II1, [Cd(L¹)₂(NCS)₂]_nII2,[Co(L¹)₂(NCS)₂(H₂O)₂]·2CH₃OH II3, [Ni(L¹)₂(NCS)₂(H₂O)₂]·2CH₃OH II4, and[ZnL²(dca)₂ ]_n II5 have been characterized by X-ray diffraction analyses. Twosymmetrical bisulphur ether ligands(III1 and III2) were synthesized utilizing5-pyridyl-2-mercapto-1,3,4-oxadiazole and two bromine alkane. III1 is1,3-bis-(5-(4-pyridyl)-1,3,4-oxadiazole-2-ylthio)propane and III2 is1,4-bis-(5-(4-pyridyl)-1,3,4-oxadiazole-2-ylthio)butane. it is a pity that thecorrespondingcompositions were not received.We parsed the crystal structures andtheir synthetical courses, and investigated their thermal properties, electronicspectrumproperties and fluorescence properties .The complex II1 crystallizes in monoclinic with space group c2c. The unit structure of the complex II1 has been connected 1D chains via C-H…S hydrogen bonding viewed down the b axis.The complex II2 belong to triclinic with space group P-1.Structure study further shows that SCN^- anions as end-to-end bridging ligands utilize both sulfur and nitrogen atoms to link cadmium(II) centres into one-dimensional double chains.The neighboring Cd-Cd distance in the same chain is alternately from 0.38 A to 0.39 A, feckly different from the same separations documented previously. Very interestingly, there are two types of eight-membered ring formed by two SCN^- anions bridging two Cd(II) centers, and the coplanar ring and the chair-conformational ring alternately array along the same chain. The complexes II3 and II4 belong to triclinic with space group P-1, and they are consistency in crystalline form exhibiting similar coordination environment and spatial configuration. there are abundant hydrogen bond effects. In addition, aromatic nucleus within the same chain show weakπ…πstacking interactions.Only a nitrogen atom within the pyridyl ring take part in coordination not showing bridging function of the ligand.Structure study shows that [N(CN)₂^-] anions as bidentate ligands to link Zn(II) centres into one-dimensional annular streamers tructure in the complex II5,and ligand L² with a spiral form connect interchain Zn(II) centres to a tube-shaped configuration.III1 and III2 exhibit the different spatial configuration due to their dissimilar connection elements. This represent not only in the discrepant space orientation of the terminal groupheteroatomic ring and alkane chain but also in the intermolecular interactions.