Crystal structures and fluorescence of two Cd(II) complexes based on N-(3-carboxyphenyl)iminodiacetic acid and 5-amino isophthailic acid

Two cadmium(II) coordination polymers, [Cd6(L1)4(H2O)11]n·4nH2O (1) and [Cd(L2)(H2O)]n·2nH2O (2), were synthesized under different pH from two multi-carboxylate ligands, N-(3-carboxyphenyl)iminodiacetic acid (H3L1) and 5-aminoisophthalic acid (H2L2), respectively. Complex 1 has a 2D layer structure, which is generated through 1D zigzag Cd…Cd chains with coexisting left-handed and right-handed helices connected together by (L1)3−. Complex 2 consists of a 2D (3, 6)-connected (4,36) net. At room temperature, complex 1 exhibits a strong emission at 442 nm upon excitation at 350 nm, and complex 2 exhibits an intense emission with double peaks at 384 and 400 nm upon excitation at 355 nm.