Synthesis of Aryl-Platinum Dinuclear Complexes via <i>o</i><i>rtho</i> C−H Bond Activation of Phenol and Transmetalation of Arylboronic Acid

The reaction of the pivalamidate-bridged platinum(III) dinuclear complex [Pt2(NH3)4(tBuCONH)2(OH2)2]4+ with phenol in water gave 2-hydroxyphenyl platinum dinuclear complex [Pt2(NH3)4(tBuCONH)2(C6H4(OH))]3+ via ortho C−H bond activation in the axial position. The identical compound and the analogous phenyl complex [Pt2(NH3)4(tBuCONH)2(C6H5)]3+ could alternatively be synthesized from the reactions of [Pt2(NH3)4(tBuCONH)2(OH2)2]4+ with the corresponding arylboronic acids via transmetalation. The reactivities of the novel aryl-Pt2 compounds toward nucleophiles and the effect of UV light irradiation were investigated. The ESR spectra showed that the axial aryl−Pt bond is homolytically cleaved by UV light irradiation to give the aryl radical and the Pt(III)−Pt(II) paramagnetic complex.