266352-76-5Relevant articles and documents
Effects of the nature of the ligand environment and metal center on the optical and electrochemical properties of platinum(II) and palladium(II) ethylenediamine complexes with heterocyclic cyclometalated ligands
Kulikova,Balashev,Kvam,Songstad
, p. 163 - 170 (2007/10/03)
Mixed-ligand cyclometalated complexes [M(C∧N)en]+ (M is Pt(II) and Pd(II); C∧N is a cyclometalating ligand on the basis of 2-(2′-thienyl)pyridine, 2-phenylpyridine, 2,6-diphenylpyridine, 2,3-diphenylpyrazine, 2,3-diphenylquinoxaline, and benzo(h)quinoline; en is ethylenediamine) were synthesized and characterized by 1H and 13C NMR, electron absorption and emission spectroscopy, and cyclic voltammetry. It was found that the lowest unoccupied molecular orbital is predominantly localized in the N-imine part of the (C∧N) ligand and that the optical and electrochemical properties of the complexes are very sensitive to changes in this part of the ligand. Mild structural changes in the (C∧N) ligands (introduction of various substituents) produce no such effect. The increase in the energy of the lowest excited state and the anodic shifts of the oxidation potentials of the complexes in going from palladium to platinum are explained in terms of enhanced stabilization of palladium 4d orbitals as compared to platinum 5d orbitals.
