Two Cd(Ⅱ) and Cu(Ⅱ) Complexes Based on 1-Butylbenzimidazole: Crystal Structures and Weak Interactions

1-Butylbenzimidazole L reacted with Cd(NO3)2·4H2O to afford complex [CdL(NO3)3H2O]·[HL] 1. The heptacoordinated Cd(Ⅱ) center adopts a distorted pentagongal bipyramidal geometry, and complex [CdL(NO3)3H2O]-entity and the protonated benzimidazium salt [HL]+ are connected via N-H···O hydrogen bond to form a dimeric unit [CdL(NO3)3H2O]·[HL]. A 3-D supramolecular network of 1 is formed through N-H···O and O-H···O hydrogen bonds together with π-π stacking interactions. Reaction of L with CuCl2 afforded a mononuclear complex, [CuL2Cl2] 2, in which the tetracoordinated Cu(II) center adopts a distorted tetrahedral geometry. In contrast, 2-D supramolecular layers of 2 are formed by C-H···Cl hydrogen bonds. The fluorescent emission spectra of L, 1 and 2 are described.