Crystal structures, in situ synthesis in aqua conditions and luminescent properties of benzimidazole ligands and cadmium coordination complexes

Three cadmium complexes, [Cd(L2)2(H2O)4]·H2O (1), [Cd(L2)2(H2O)4]·8H2O (2), [Cd2(L3)2(SO4)(4,4′-bpy)0.5(H2O)3]·2.5H2O (3) have been obtained from L1 ligand and auxiliary ligand in hydrothermal conditions. The crystal structures reveal that L2·H2O can be transformed from L1 directly in hot water conditions, while L3 emerge in coordination complex via in situ reactions of L1 ligand. Complexes 1 and 2 are zero dimensional coordination complexes and there are interesting T12(4) water tapes exist in complex 2. 3 is three dimensional supramolecular structure which is comprised of interpenetrated one dimensional chains. The luminescent properties have been measured and show that the emission peaks are similar between L2·H2O and complex 1, but take place bathochromic shift for complex 2 which should be tentatively relative to conjugation of organic ligands and metal coordination reaction.