Reactivity of a binuclear Ru(II) N2-bridged complex towards phosphines:: facile access to novel mono and binuclear phosphorous derivatives.: X-ray structural characterization of two unusual binuclear complexes containing 'pincer' ligands:: [{RuCl2(η3-NN′N)}2(μ-η2-P2)] (NN′N=2,6-bis[(dimethylamino)methyl]pyridine;: P2=1,3-bis[(diphenylphosphino)methyl]benzene or 1,3-bis(diphenylphosphino)propane)

Treatment of the dinitrogen bridged complex [{RuCl2(eta(3)-NN'N)} (2)(mu-N-2)] (1, NN'N = 2,6-bis[(dimethylamino)methyl]pyridine) with a variety of monodentate phosphorous ligands results in the formation of the corresponding mononuclear derivatives [RuCl2(eta(3)-NN'N)(PR3)] (R-3 = Ph-3, 2; Ph2H, 3; Me-3, 4; (OMe)(3), 5). When potentially bidentate bis-phosphines are used, the results are found to be ligand dependent: with one or two equivalents of bis(diphenylphosphino)methane (dppm), the only product observed is the mononuclear derivative [RuCl2(eta(2)-NN'N)(eta(2)-dppm)] (6), which contains the diphosphine acting as a chelating ligand. However, the use of bis-phosphines such as 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp) or 1,1'-bis[di(p-tolyl)phosphino]ferrocene (dtpf), results in the formation of binuclear products: [{RuCl2(eta(3)-NN'N)}(2)(mu-dppe)] (7), [{RuCl2(eta(3)-NN'N)}(2)(mu-dppp)] (8) and [(RuCl2(eta(3)-NN'N))(2)(mu-dtpf)] (9), respectively. In these cases, the phosphine ligands are bridging between two Ru centered moieties. The X-ray structure of complex 8 is reported. Treatment of complex 1 with the potentially terdentate phosphine ligand 1,3-bis[(diphenylphosphino)methyl]benzene (PCHP) affords the binuclear derivative [{RuCl2(eta(3)-NN'N)}(2)(mu-eta(2)-PCHP)] (10). Compound 10 has been characterized by X-ray diffraction methods and represents the first example in which a Ru complex contains a bridging and noncyclometallated PCHP 'pincer' ligand. (C) 1999 Elsevier Science S.A. All rights reserved.