Synthesis and crystal structures of silver(i), palladium(ii), zinc(ii) and cobalt(ii) complexes of the ditoptic ligand 1,3-bis(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene
Complexes of 1,3-bis(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene (bitmb) with silver(I), palladium(II), zinc(II) and cobalt(II) salts have been characterized in the solid state by single-crystal X-ray analysis. The topology of the structures in the solid state, namely finite versus infinite, is found to dependent on the coordination geometry of the metal atoms. For Ag(I) (linear N2 geometry) and Pd(II) (square-planar N4), crystallization with bitmb produces an M2L2 cyclic dimer of composition [Ag2(bitmb)2](PF6)2·2CH3CN (1) or an M2L4 cage complex [Pd2(bitmb)4]Cl4·8H2O·1.5CH3CN (2). For Zn(II) (tetrahedral N2O2) or Co(II) (octahedral N6), crystallization with bitmb produces a 1D zigzag chain network of [Zn(bitmb)(CH3CO2)(C2H5OH)](OH) (3) or an infinite 1D poly-macrocycle chain network [Co(bitmb)2(CH3CN)2](ClO4)2·2C2H5OH (4). It is also found that the conformations of the bitmb ligand are obviously controlled by the coordination number of the central metal ions. When coordinated with silver(I) (coordination number n = 2), palladium(II) (n = 4) or zinc(II) (n = 4), bitmb shows a cis,cis-conformation, but in the case of cobalt(II) (n = 6), bitmb shows a trans,trans-conformation. The results also show that the π⋯π interactions together with the hydrogen bonds co-affect inorganic supramolecular formation.