Part A: Bridging and Chelating Roles of Triphos in Stabilizing Binuclear Platinum (II) Complexes   Part B: Six-Membered Cycloplatinated Complexes Containing 2-benzylpyridine: Synthesis and Kinetics of a Reaction with

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Ph.D. DISSERTATION IN

INORGANIC CHEMISTRY

Part A: Bridging and Chelating Roles of Triphos in Stabilizing Binuclear Platinum (II) Complexes

Part B: Six-Membered Cycloplatinated Complexes Containing 2-benzylpyridine: Synthesis and Kinetics of a Reaction with MeI

Abstract

The diorganoplatinum (II) complexes [PtR₂(triphos-P,P^′ )] (1; R = Me, p-MeC₆H₄ and triphos = bis(2-(diphenylphosphino)ethyl)phenylphosphine) react with cyclometalated platinum complexes [PtR^′(C^˄N)(SMe₂)] (2; R^′ = Me, p-MeC₆H₄ and C^˄N is deprotonated 2- phenylpyridine (ppy) or deprotonated benzo[h]quinoline (bhq)) to give the cyclometalated diplatinum (II) complexes [Pt₂R₂R^′(C^˄N)(triphos)] (3). In these compounds, triphos acts as both a chelating and bridging ligand to stabilize the produced diplatinum complexes. The complexes 3 were characterized by multinuclear NMR spectroscopy and elemental microanalysis. The crystal structure of complex 3f (R = Me, R^′ = p-MeC₆H₄, and C^˄N = bhq) as the first example of an X-ray structural determination of a diplatinum complex, was further determined by X-ray crystallography.

New six-membered cycloplatinated (II) complex [PtMe(C^N)(PPh₃)], C, in which C^N = deprotonated 2-benzylpyridine (bzpy), was synthesized by the reaction of [PtMe(bzpy)(DMSO)], B, with excess of PPh₃ ligand. The complex B for the first time has been separated and its structure was deduced from ¹H NMR spectrum. The reaction of complex C with MeI gave the cyclometalated Pt (IV) complex [PtMe₂I(bzpy)PPh₃], D. On the basis of comparative kinetic studies, rate of reaction of the six-membered complex C was faster than those the five-membered complexes. This was attributed to effects of ring size of bzpy ligand as compared with that of five-membered ligands. The complexes C and D were fully characterized using multinuclear (¹H and ³¹P) NMR spectroscopy and elemental analysis.