Dinuclear cyclometallated platinum(III) complexes. Relationship between molecular structure and crystal packing

Treatment of the dimer chloro-bridged cyclometallated platinum(II) complex [Pt(μ-Cl)(N,C-2-PhPy)]2 with the heterocyclic thiones 2-mercaptobenzimidazole (mbzimH), 2-mercaptoimidazoline (mimH), 5-nitro-2-mercaptobenzimidazole (NO2mbzimH), 2-mercaptobenzothiazole (mbztzH) and 2-mercaptobenzoxazole (mbzoxzH) gave the dinuclear complexes [PtCl(μ2-L)(N,C-2-PhPy)]2 [L = (mbzimH), (mimH), (NO2mbzimH), (mbztzH) and (mbzoxzH)] with the platinum atoms in the uncommon (III) oxidation state. The complexes consist of dinuclear molecules in which two metal bonded platinum atoms are coordinated in a slightly distorted octahedral environment to a phenylpyridine, a terminal chloride and two bridging mercaptoimidazol ligands, with the only difference being the nature of the bringing ligands. The study of the crystal structures show the existence of a wide variety of intermolecular interactions, ranging from typical N–H⋯Cl, N–H⋯S hydrogen bonds through C–H⋯Cl, C–H⋯S, C–H⋯O, C–H⋯π interactions to weak π–π stacking or C–Cl⋯π interactions. Even though a number of similarities were observed in the crystals, this study shows the influence that minor changes in the molecular structure have in the number and nature of the intermolecular interactions which determine the packing within the crystals and also determines the molecular structure itself.

New Pt(II) dimeric cyclometallated complexes with [N,S] bridging ligands have been synthesized The introduction of small changes in their molecular causes large changes in the intermolecular interactions and in the crystal packing. Furthermore, in one of these complexes the presence of weak C–Cl⋯π interactions with solvent molecules significantly modifies the molecular conformation.Figure optionsDownload as PowerPoint slide