Oxidative Addition Reactions of Binuclear Organoplatinum Complexes with Ditopic Ligands

The chemistry of bis[dimethylplatinum(II)] complexes of four ditopic ligands based on anthracene [1,8-C14H8(N=CH-2-C5H4N)2, L1, and 1,8-C14H8(CC-4-C6H4-N=CH-2-C5H4N)2, L2] or 2,7-di-t-butyl-9,9-dimethyl-xanthene [4,5-C23H28O(N=CH-2-C5H4N)2, L3, and [4,5-C23H28O(C(=O)NH-4-C6H4-N=CH-2-C5H4N)2, L4] backbones. Each complex [(PtMe2)2(L1)] - [(PtMe2)2(L4)] reacted with MeI to give the corresponding platinum(IV) complex [(PtIMe3)2(L1)] - [(PtIMe3)2(L4)] as a mixture of two isomers which equilibrated slowly at room temperature.  The complex [(PtMe2)2(L3)] also underwent oxidative addition with PhCH2Br, I2 or HgBr2 to give [(PtBrMe2CH2Ph)2(L3)], [(PtI2Me2)2(L3)] or [(PtBrMe2)2(Hg)(L3)] respectively, the last containing a Pt-Hg-Pt unit.  Finally, the complexes [(PtIMe3)2(L3)] and [(PtIMe3)2(L4)] reacted with silver triflate and pyrazine (C4H4N2) to give the complexes [(PtMe3)2(C4H4N2)(L3)][O3SCF3]2 and [(PtMe3)2(C4H4N2)(L4)][O3SCF3]2, respectively, each of which contains a bridging pyrazine ligand.