Binuclear Platinum(IV) Complexes with Bridging Amidoalkyl Groups and Their Self-Assembly through Hydrogen Bonding

Oxidative addition of the reagents {4-BrCH2C6H4-(CH2)x-C(═O)NH-(CH2)y}2Z to [PtMe2(bu2bipy)], bu2bipy = 4,4′-di-t-butyl-2,2′-bipyridine, gave the corresponding diplatinum(IV) complexes [{PtBrMe2(bu2bipy)-4-CH2C6H4-(CH2)x-C(═O)NH-(CH2)y}2Z], with Z = o-, m-, or p-C6H4 and x, y = 0 or 1; or Z = 1,2-C2H4 and x = y = 0. The complexes are formed selectively by trans oxidative addition to both platinum(II) centers and contain long bridging alkanediyl ligands containing two amide units in the backbone. Several iodide analogues were prepared by displacement of bromide from the bromoplatinum(IV) complexes by reaction with lithium iodide, and in one case, a chloride derivative was formed by the reaction of a bromoplatinum(IV) complex with solvent carbon tetrachloride. In the solid state, the compounds undergo self-assembly to form supramolecular polymers, ribbon polymers, or a sheet structure by forming intermolecular hydrogen bonds of the type NH···O═C, NH···BrPt or NH···ClPt.