Pseudohalogeno Complexes of Sterically Hindered Tripyrrinatopalladium (TrpyPd) Fragments
作者:Martin Bröring、Serguei Prikhodovski、Carsten D. Brandt、Esther Cónsul Tejero
DOI:10.1002/zaac.200600346
日期:2007.3
Eight new pseudohalogenocomplexes of stericallyhinderedTrpyPdfragments 4–11 have been prepared by salt metathesis in one step from known trifluoroacetates TrpyPdOAcF1–3, using sodium salts of N3, NCO, NCS, NCSe, dicyanamide (dca) and tricyanomethanide (tcm) anions. Despite the propensity of the co-ligands to bind to two or more metal centres in a bridging coordination mode all new complexes have been
A five coordinate Pd<sup>II</sup>complex stable in solution and in the solid state
作者:Martin Bröring、Carsten D. Brandt
DOI:10.1039/b305547g
日期:——
The treatment of the strained complex TrpyPdOAc(F) 1 with NaBAr(F), followed by the addition of trimethylphosphine, yields the stable cationic 16VE- or 18VE-complexes 3 and 4, depending on the amount of phosphane added.
The formation of cationic palladium(II)complexes [TrpyPd(II)]X-+(-) by salt metathesis of the respective trifluoroacetates with different salts of weakly coordinating anions X- was investigated. With non-hydrolizable counterions, cationic mono- and dinuclear complexes are observed depending on the nature of the anion X- and the solvent. The mononuclear cations, which are only formed with X = BArF, most probably carry a weakly bound molecule of dichloromethane at the fourth coordination site of Pd-II. When treated with diazoalkanes, only these are sufficiently reactive to form carbene complexes. Four- and five coordinate Lewis base adducts [TrpyPd(II)L](+) with L = CH3NC, tBuNH(2), PMe3, PEt3 and PiPr(3) and [TrpyPd(II)L(2)](+) with L = PMe3 were prepared from the mononuclear cations [TrpyPd(II)]+BArF-. From structural studies it becomes apparent, that the formation of stable five coordinate Pd-II species is restricted to medium size ligands and depends on the delicate balance between the steric influence of L and the strain, which is induced on the TrpyPd(II) unit. (c) 2005 Elsevier B.V. All rights reserved.