Synthesis, crystal structures and characterization of three cadmium(II) metal–organic coordination complexes constructed from flexible bis(imidazole) and carboxybenzaldehyde ligands

Three new cadmium(II) coordination complexes, namely, [Cd2(1,2-bix)4(L)4]n (1), [Cd(1,3-bix)(L)2]n·H2O (2), [Cd(1,4-bix)(L)2H2O)]n·2.5H2O (3) have been synthesized using 4-carboxybenzaldehyde (HL) and 1,n-bis(imidazol-l-ylmethyl)benzene (1,n-bix; n = 2, 3, 4) as ligands. These complexes were structurally characterized by single-crystal X-ray crystallography and further characterized by FT-IR spectroscopy and thermogravimetric analysis (TGA). Complex 1 is a binuclear, complex 2 possesses a 1D double chain. Compound 3 features a 1D zigzag chain, assembled into a 2D layer structure by weak π–π interactions. The photoluminescent properties of the compounds 1–3 were also investigated.