Binuclear complexes of ruthenium with diphosphines and bridging benzene-1,2-diamide. X-Ray crystal structure of [Ru2{µ-1,2-(NH)2C6H4}{µ-(Ph2P)2CH2}(CO)2(PPh3)2]·C6H5Me

Abstract

The binuclear complex [Ru2{µ-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{µ-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{µ-1,2-(NH)2C6H4}(µ-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{µ-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{µ-1,2-(NH)2C6H4}(CO)3(dppb-P)(dppb-PP′)]9, [Ru2{µ-1,2-(NH)2C6H4}(µ-dppb)(CO)2(PPh3)2]10, [Ru2{µ-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 P21/n, with a= 18.563(8), b= 21.066(9), c= 17.936(7)A, β= 110.47(2)° 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)A, consistent with a metal–metal bond.