Cd(II)-Based Coordination Polymers and Supramolecular Complexes Containing Dianiline Chromophores: Synthesis, Crystal Structures, and Photoluminescence Properties

Five new coordination compounds that included three coordination polymers and two supramolecular complexes were obtained by reactions of different cadmium salts (tetrafluoroborate, nitrate, and perchlorate) with dianiline chromophores, 4,4 '-diaminodiphenylmethane (ddpm), and 4,4 '-diaminodiphenylethane (ddpe). The crystal structures were studied by single-crystal X-ray analysis. The coordination arrays with the ddpm chromophore included {[Cd(OH)(H2O)(ddpm)2](BF4)}n (1) as a one-dimensional (1D) coordination garland chain, {[Cd(NO3)(ddpm)2](H2O)(NO3)}n (2) as a two-dimensional (2D) coordination layer, and [Cd(bpy)2(ddpm)2](ddpm)(NO3)2 (3) as a supramolecular complex. The products with the ddpe chromophore were identified as {[Cd(phen)2(ddpe)](ClO4)2}n (4) in the form of a linear coordination chain and [Cd(phen)3](ClO4)2(ddpe)0.5(CH3CN)0.5 (5) as a supramolecular complex. The extension of coordination arrays in 1, 2, and 4 was achieved via dianiline ligands as bidentate linkers and additionally via bridging of nitrate anions in 2. The diversification of products became possible due to usage of 2,2 '-bipyridine (bpy) and 1,10-phenanthroline (phen) as co-ligands forming the terminal corner fragments [Cd(bpy)2]2+, [Cd(phen)2]2+, and [Cd(phen)3]2+ in 3-5, respectively. The assembling of coordination entities occurred via the interplay of hydrogen bonds with the participation of amino groups, water molecules, and inorganic anions. Two dianilines were powerful luminophores in the crystalline phase, while the photoluminescence in 1-5 was considerably weaker than in the pure ddpm and ddpe luminophores and redistributed along the spectrum.