(Z)-2-(2-(Anthracen-9-ylmethylene)hydrazineyl)pyrimidine-rhodium(III): Crystal Structure and DNA Binding Property

A new rhodium(III) complex of a 9-anthrahydrazone ligand ((Z)-2-(2-(Anthracen-9-ylmethylene)hydrazineyl)pyrimidine, 9-PMAH) is six-coordinated respectively by one bidentate ligand, one solvent DMSO, and three chlorides, to form a distorted octahedral coordination geometry. The ligand chelates to Rh(III) via the hydrazone N atom (N1) and pyrimidine N atom (N3), whereas DMSO coordinates to Rh(III) via the S atom. The three chloride ligands (Cl1, Cl2, and Cl3) are in a mer-configuration of the octahedron, with the DMSO cis- to the pyrimidine nitrogen. In solution, the complex may exist in the positively charged species, [RhIIICl2(DMSO)(9-PMAH)]+, but can be stable in this mode for no less than 48 h. It was suggested by the fluorescence spectroscopic analysis that the complex showed much higher intercalative binding ability with ct-DNA than the typical DNA intercalator, EtBr.