Syntheses And Crystal Structures Of The Complexes Of 2,5-disubstituted-1,3,4-thiadiazole

1,3,4-Thiadiazoles are important five-membered heterocyclic compounds,and widely used in medicines,agricultures and industries.In order to study the transition-metal complexes with 1,3,4-thiadiazole compounds,we have synthesized some new 2,5-disubstituted-1,3,4-thiadiazole compounds,and the single-crystal structures of the complexes were investigated.The works in this paper are as follows.1.Eight compounds of 2,5-disubstituted-1,3,4-thiadiazole were synthesized.The single crystal structure of 2-phenyl-5-(2-pyridyl)-1,3,4-thiadiazole was determined by X-ray analysis.It crystallizes in monoclinic system and the space group is P21/c.The thiadiazole ring,pyridine ring and benzene ring are in a common plane.2.Four transition-metal complexes of[Ag₂(?-L)₂(NO3)₂],[CdL₂(NO3)₂],[Cd₂L₂(?-Cl)₂Cl2(H₂O)₂]and[CdL₂(SCN)₂2]were synthesized from 2-ethyl-5-(2-pyridyl)-1,3,4-thiadiazole(L),and their single-crystal structures were determined.3.The complex of[Ag₂(?-L)₂(NO3)₂]is a double-bridge binuclear silver(?)complex bridged by two ligands of L.The distance of Ag1-Ag1? is 4.1369(29)A.The central silver(?)atoms have distorted tetrahedral geometries with AgN3O.The complex of[Cd₂L₂(?-Cl)₂Cl2(H₂O)₂]is a double-bridge binuclear cadmium(?)complex bridged by two chloride anions.The distance of Cd1-Cd1? is 3.7213(4)A,and the central cadmium(?)atoms have distorted octahedral geometries with CdN2Cl3O.The central cadmium(?)atom of[CdL₂(NO3)₂]has a distorted octahedral geometry with CdN4O2,and that of[CdL₂(SCN)₂2]has a distorted octahedral geometry with CdN6.