New palladium and platinum complexes based on ligands bearing nitronylnitroxide radicals. Magnetic properties and catalytic activity in oxidation of alcohols

Abstract

In the last two decades the field of molecular magnetic materials has become a rapidly growing interdisciplinary area in pure and applied sciences. These materials find their application in developing magnetic devices, molecular electronics, nonlinear optics, sensing devices, nanosized materials and catalysts. Coordination chemistry provides a powerful tool to design these materials in the form of discrete molecular systems, ID chains, 2D layers or 3D networks. In the present study new palladium(II) and platinum(II) transition metal complexes based on mixed ligands 2,2' bipyridine and 1,10-phenanthroline and their dimethyl substituted derivatives with different pyridylnitronylnitroxide were successfully synthesized. Characterization of these complexes using elemental analysis, UV-visible, FT-IR and ESR spectroscopy was carried out. The magnetic susceptibility of a series of compounds was measured down to 4 Kelvin. Cyclic voltametry studies were performed on these complexes to investigate the behavior of the electroactive centers and determine the different redox couples. Single crystal X-ray diffraction analyses were conducted on a series of complexes to determine their solid state molecular structure and the nature of their packing modes in order to rationalize their physical properties. Different pyridylnitronylnitroxide radicals synthesized in the present study were used for the first time to evaluate their catalytic activity in the oxidation of alcohols.