Supramolecular Macrocyclic Pd(II) and Pt(II) Squares and Rectangles with Aryldithiolate Ligands and their Excellent Catalytic Activity in Suzuki C-C Coupling Reaction

Addition of 1,4-benezenedithiol and 4,4'-biphenyldithiol to M(OTf)(2) (M = cis-[Pt(PEtw(3))(2)]((2+)) or cis-[Pd(dppe)]((2+))) (dppe = 1,2-bis(diphenylphosphino)ethane) gave self-assembled tetranuclear complexes [M-2{S(C6H4)(n)S}](2)(OTf)(4) (n = 1, 2). The same reaction with 1,4-benezenedimethanethiol yielded octanuclear supramolecular coordination complexes (SCC) [M-2{SCH2C6H4CH2S}](4)(OTf)(8). These complexes were characterized by NMR, mass, and UV-vis spectroscopies, cyclic voltammetry, as well as density functional theory studies and represent the first examples of SCCs constructed by thiolate groups and square-planar metal ions. The rectangular shape of tetranuclear complexes and square shape of octanuclear complex are confirmed by single-crystal structures and computational studies. The palladium complexes showed excellent catalytic activity in Suzuki C-C cross-coupling reactions with high turnover numbers (2 x 10(7)), even with low catalyst loading.