One novel complex obtained through copper-mediated conversion of 2,5-bis(3-pyridyl)-1,3,4-oxadiazole: Structure, in situ formation of ligand, and luminescence properties

One new complex [Cu₃(L1)I₂]_n (1; L1 = 3,5-bis(3-pyridyl)-1,2,4-triazolate) has been obtained through unprecedented in situ copper-mediated conversion of 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (L2) into L1 with aqueous ammonia under solvothermal conditions. It is very remarkable that, if considering the weak bond of Cu2-I2 [2.97 Å], the whole neutral framework adopts an unprecedented 6,8-connected 2-nodal 3-D network; while regarding [(Cu1)(I2)₂]^1- aggregates as cavity anionic pieces, the host cationic framework adopts a 6-connected uninodal net of α-Po primitive cubic topology. The new complex 1 exhibits strong fluorescence emission with long multicomponent fluorescent lifetimes at room temperature. Its emissive excited state is primarily attributed to the (M + X)LCT based on the results of the DFT calculation.