Compounds containing weak, non-covalent interactions to the metal in the backbone of 1,1′-bis(phosphino)metallocene ligands

The reactions of Na[BArF] (BArF = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate) with a series of [Pd(dpEMc)Cl-2] (dpEMc = 1,1'-bis(diphenylphosphino)ruthenocene (dppr), 1,1'-bis(diphenylphosphino)osmocene (dppo) or 1,1'-bis(diphenylarsino)ferrocene (dpaf)) compounds were examined. The reaction of Na[BArF] with [Pd(dppMc)Cl-2] (dppMc = dppr or dppo) resulted in the formation of the corresponding chloride-bridged dimers, [Pd(dppMc)(mu-Cl)](2)(2+), which were structurally characterized. However, these dimers appear to be unstable in CH2Cl2 and partially (Ru) or fully (Os) convert into the corresponding monomers, [Pd(dppMc)Cl](+), which are proposed to have a weak, non-covalent M-Pd (M = Ru or Os) interaction. Similar compounds, [Pd(dppo)PPh3](2+) and [Pt(dppMc)PPh3](2+) (M = Fe (1,1'-bis(diphenylphosphino)ferrocene (dppf)) or Os (dppo)), were also prepared and structurally characterized. These compound also exhibit weak, non-covalent M-Pd/Pt interactions. In addition, the electrochemical properties of these compounds were examined by cyclic voltammetry. (C) 2015 Elsevier Ltd. All rights reserved.