Cadmium(II) and cobalt(II) complexes generated from benzimidazole-5-carboxylate: Self-assembly by hydrogen bonding and [formula omitted] interactions

Abstract

Self-assembly of L − (HL=benzimidazole-5-carboxylic acid) with Cd(II) and Co(II), respectively, by layer-separating diffusion method at ambient temperature gives rise to two new supramolecular architectures [(CdL 2·H 2O)·2CH 3OH] n ( 1) and {[CoL 2(H 2O) 2]·2H 2O} n ( 2), both of which are stabilized by the hydrogen bonding interactions and the intermolecular π – π interactions. 1 crystallizes in the triclinic system, space group P - 1 , with cell parameters M = 516.78 , a = 9.084 ( 2 ) Å , b = 10.063 ( 10 ) Å , c = 11.533 ( 8 ) Å , α = 90.21 ( 11 ) ° , β = 99.48 ( 6 ) ° , γ = 98.34 ( 9 ) ° , V = 1028.4 ( 12 ) Å 3 , Z = 2 , R 1 [ I > 2 σ ( I ) ] = 0.0257 , w R 2 [ I > 2 σ ( I ) ] = 0.0719 . 2 crystallizes in the monoclinic system, space group C2 /c, with cell parameters M = 453.27 , a = 16.119 ( 2 ) Å , b = 8.8952 ( 13 ) Å , c = 14.195 ( 2 ) Å , β = 118.507 ( 2 ) ° , V = 1788.5 ( 4 ) Å 3 , Z = 4 , R 1 [ I > 2 σ ( I ) ] = 0.0802 , w R 2 [ I > 2 σ ( I ) ] = 0.1515 . Complex 1 displays a remarkable three-dimensional (3-D) structure with unusual channels generated from the interlayer voids. Complex 2 exhibits the 3-D structure consisting of 1-D zigzag chains. The thermal and fluorescence properties associated with their crystal structures have been measured, and complex 1 displays intense blue emission in the solid state.