Crystal structure, supramolecular self-assembly and interaction with DNA of a mixed ligand manganese(II) complex

Abstract

A mixed ligand manganese(II) complex, [Mn(sal)(phen)2]ClO 4 (1) (sal = salicylaldehyde, phen = 1,10-phenanthroline), has been synthesized and characterized by elemental analysis and single crystal X-ray diffractometry. The structural analysis revealed that complex 1 crystallizes in the monoclinic space group P21/n. The asymmetric unit of the complex is comprised of [Mn(sal)(phen)2]+ complex cation and uncoordinated perchlorate anion. The manganese(II) is located in a seriously distorted octahedral MnN4O2 coordination environment. Four types of π-π stacking modes involving phenanthroline and salicylaldehyde ligands are involved in the supramolecular self-assembly. These aromatic stacking interactions cooperate with hydrogen bonding to assemble the complex into a fascinating 3D supramolecular architecture. Electronic absorption spectroscopy and fluorescence titration studies of the interaction between complex 1 and calf thymus DNA suggest an intercalative binding mode with a constant of 7.97×103 L mol-1 and a Stern-Volmer quenching constant of 1.34×104 L mol-1. © 2011 Sociedade Brasileira de Química.