Syntheses of Polythioethers Tethered with Bulky Aryl Groups and Their Complexation with Late-Transition Metals

Abstract

New types of o-phenylene-bridged polythioethers tethered with extremely bulky aryl groups at their terminal sulfur atoms, such as TbtS(o-Phen)S(o-Phen)S(o-Phen)STbt (1) and TbtS(o-Phen)S(o-Phen)SS(o-Phen)S(o-Phen)STbt (2) (Tbt = 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl, o-Phen = o-phenylene), were synthesized and subjected to the complexation with several kinds of late-transition metals. In the case of polythioether 1, the reaction with RhCl₃·3H₂O in benzene/EtOH resulted in the formation of a unique bimetallic complex, in which a part of ligand 1 is lost and the resulting sulfur atom is directly bound to the other Rh metal center. Interestingly, similar treatment of 1 with IrCl₃·3H₂O afforded ethyl-coordinated mononuclear Ir complex. Furthermore, 1 underwent complexation with Na₂PdCl₄ in EtOH to give the corresponding square planar dichloropalladium complex coordinated with two inner sulfur atoms of 1, while the S₆-ligand 2 reacted with excess of Pd(PPh₃)₄ in benzene to afford a quite interesting trinuclear Pd complex multi-step metal insertion reactions.