Syntheses, characterization and structures of 2-(2-pyridyl)-4-methylcarboxyquinoline ligand and bis(2,2 '-bipyridine)-2-(2-pyridyl)-4-methylcarboxyquinoline ruthenium (II) hexafluorophosphate

摘要

The synthesis, characterization and X-ray single crystal structure of a 2-(2-pyridyl)-4-methylcarboxyquinoline diimine ligand (pqme) and its corresponding bis(2,2'-bipyridine)-2-(2-pyridyl)-4-methylcarboxyquinoline ruthenium (II) hexafluorophosphate Ru(bpy)(2)(pqme)(PF6)(2) complex is described. H-1, H-1-H-1 COSY, H-1-H-1 TOCSY, C-13 NMR, FT-IR, elemental and mass spectrometric analyses were used to characterize the products and fully ascertain their structures. The complex exhibited two well-resolved MLCT transitions in the visible region and a ligand-based transition in the UV region. The cyclic voltammogram of the complex showed a reversible Ru(III)/Ru(II) couple and three well-defined ligand-based reductions. X-ray diffraction analyses provided further insight as to the conformations and geometry of both products. A trans conformation is shown in the solid state as expected for the 2-(2-pyridyl)-4-methylcarboxyquinoline ligand, and a distorted octahedral geometry for the bis(2,2'-bipyridyl)-2-(2-pyridyl)-4-methylcarboxyquinoline ruthenium (II) hexafluorophosphate complex due to alpha hydrogens of the opposing N-N ligands have been revealed. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 44]