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

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 [(CdL2.H2O).2CH3OH]n (1) and {[CoL2(H2O)2].2H2O}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)A, b=10.063(10)A, c=11.533(8)A, α=90.21(11)o, β=99.48(6)o, γ=98.34(9)o, V=1028.4(12)A3, Z=2, R1[I>2σ(I)]=0.0257, wR2[I>2σ(I)]=0.0719. 2 crystallizes in the monoclinic system, space group C2/c, with cell parameters M=453.27, a=16.119(2)A, b=8.8952(13)A, c=14.195(2)A, β=118.507(2)o, V=1788.5(4)A3, Z=4, R1[I>2σ(I)]=0.0802, wR2[I>2σ(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