Syntheses, Crystal Structures And Characterization Of The Complexes Of 2?substituted?5?pyridyl?1,3,4?thiadiazole

1,3,4-Thiadiazoles are important heterocyclic compounds widely used in the fields of pesticides,medicines and chemical materials.In order to study the 1,3,4-thiadiazole transition metal complexes,we synthesized six novel 2-substituted-5-pyridyl-1,3,4-thiadiazole compounds,and the crystal structures and properties of the complexes were investigated.The works in this paper are as follows.1.Six 2-substituted-5-pyridyl-1,3,4-thiadiazole compounds were synthesized.The ultraviolet and fluorescence spectra of the 2-methyl-5-?2-pyridyl?-1,3,4-thiadiazole?L?and2-?p-methylphenyl?-5-?2-pyridyl?-1,3,4-thiadiazole?L'?were determined,and the fluorescence emission wavelength of ?_max are 415 nm and 390 nm,respectively.2.Seven metal complexes are prepared from 2-methyl-5-?2-pyridyl?-1,3,4-thiadiazole?L?and 2-?p-methylphenyl?-5-?2-pyridyl?-1,3,4-thiadiazole?L'?,and their crystal structures were determined.The complex of[CuL₂Cl₂]·2H₂O is a monomeric metal complex,and the central copper???atom has a distorted octahedral geometry?CdN₄Cl₂?.The complexes of[CdL₂?NO₃?₂]and[CdL'₂?NO₃?₂]·1.5H₂O have similar structures.The central cadmium???atoms have distorted octahedral geometries?CdN₄O₂?,and the two ligands are in cis.The complexes of[Ag₂??-L?₂?NO₃?₂]and[Ag₂??-L'?₂?NO₃?₂]are double-bridged dinuclear silver??40??complexes bridged by two ligands.The central atoms of Ag1 and Ag2 have similar distorted tetrahedral geometries with AgN₃O.The complex of[Cd₂L₂??-Cl?₄]_n is a double-bridged cadmium???polymeric complex bridged by two chloride ions,and the central cadmium???atoms have distorted octahedral geometries with CdCl₄N₂.The complex of[Cd₂L₂??-SCN?₄]_n is a double-bridged cadmium???polymeric complex bridged by two thiocyanate ions,and the central cadmium???atoms have distorted octahedral geometries with CdN₄S₂.3.The TGA,UV and fluorescence spectra of[CuL₂Cl₂]·2H₂O,[CdL₂?NO₃?₂],[Ag₂??-L?₂?NO₃?₂],[Cd₂L₂?m-Cl?₄]_n,[Cd₂L₂??-SCN?₄]_n,[CdL'₂?NO₃?₂]·1.5H₂O and[Ag₂??-L'?₂?NO₃?₂]were measured.In the fluorescence spectra of[CuL₂Cl₂]·2H₂O,[Ag₂??-L?₂?NO₃?₂],[Cd₂L₂??-Cl?₄]_n,[Cd₂L₂??-SCN?₄]_n and[CdL₂?NO₃?₂],the fluorescence intensity is weaker than that of the ligand L,and blue shifts are observed.