BINUCLEAR COMPLEXES OF RUTHENIUM WITH DIPHOSPHINES AND BRIDGING BENZENE-1,2-DIAMIDE - X-RAY CRYSTAL-STRUCTURE OF [RU-2(MU-1,2-(NH)2C6H4)(MU-(PH2P)2CH2)(CO)2(PPH3)2]C6H5ME

The binuclear complex [Ru2{mu-1,2-(NH)2C6H4}(CO)4(PPh3)2] 1 reacts with the diphosphines (Ph2P)2X [X = C2H4 (dppe), cis-C2H2 (dppen), 1,2-C6H4 (dppbz), C3H6 (dppp) and C4H8 (dppb)], in boiling toluene, to give purple solutions from which the yellow compounds [Ru2{mu-1,2-(NH)2C6H4}(CO)3(PPh3)(diphosphine)] [dppe, 2; dppen, 3, dppbz, 4; dppp, 5; or dppb, 6 can be obtained after purification on an Al2O3 column and crystallization from toluene-hexane solutions. The reaction of 1 with (Ph2P)2CH2 (dppm), in boiling toluene or xylene, affords [Ru2{mu-1,2-(NH)2C6H4}-(mu-dppm) (CO)2(PPh3)2] 7 as the unique product. All these new complexes can be obtained in good yields by reaction of [Ru{1,2-(NH)2C6H4}(PPh3)(diphosphine)] with [Ru(CO)3(PPh3)2] in boiling mesitylene. Compound 1 also reacts with [Ru{1,2-(NH)2C6H4}(PPh3)3] or [RuH2(PPh3)4] in boiling xylene to give [Ru2{mu-1,2-(NH)2C6H4}(CO)3(PPh3)3] 8 which easily regenerates 1 by reaction with CO. An excess of diphosphine (except for dppm) in the reaction with 1 produced the mononuclear complexes [Ru{1,2-(NH)2C6H4}(CO)(diphosphine)] and [Ru(CO)2(PPh3)(diphosphine)] and for the reaction with dppb the complexes [Ru2{mu-1,2-(NH)2C6H4}(CO)3(dppb-P)(dppb-PP')] 9, [Ru2{mu-1,2-(NH)2C6H4}(mu-dppb)(CO)2(PPh3)2] 10, [Ru2{mu-1,2-(NH)2C6H4}(CO)2(dppb)2] 11 and [Ru(CO)2-(dppb-P)(dppb-PP')] 12 were also detected or isolated. All complexes have been characterized by elemental analysis and by IR and NMR spectroscopy. The structure of the toluene solvate of 7 has been determined by X-ray diffraction methods: monoclinic, space group P2(1)/n, with a = 18.563(8), b = 21.066(9), c = 17.936(7) angstrom, beta = 110.47(2)-degrees and Z = 4. The structure was solved from diffractometer data by Patterson and Fourier methods and refined by full-matrix least squares to R = 0.0524 for 6679 observed reflections. The two Ru atoms are doubly bridged by the nitrogen atoms of the 1,2-diimine ligand with a short Ru-Ru separation, 2.562(1) angstrom, consistent with a metal-metal bond.