ADDITION OF CH3CO2H AND HBF4 TO ALKYNYL COMPLEXES OF RUTHENIUM(II) AND OSMIUM(II)

The bis(alkynyl) complex [OS(C2Ph)2(CO)(PiPr3)2] (1) reacts with CH3CO2H to give the vinylacetato derivative [Os(C2Ph){C(=CHPh)OC(O)CH3}(CO)(PiPr3)2] (3). The protonation of 3 with HBF4 in diethyl ether leads to the carbene compound [Os(C2Ph){=C(CH2Ph)OC-(O)CH3}(CO)(PiPr3)2]BF4 (4). On the other hand, reaction of the analogous ruthenium complex [Ru(C2Ph)2(CO)(PiPr3)2] (2) with CH3CO2H affords [RU(C2Ph)(eta2-O2CCH3)(CO)(PiPr3)2] (5) and phenylacetylene. 5 reacts with HBF4 in acetone to give [Ru{C(=CHPH)OC(O)CH3}(CO)-{eta1-OC(CH3)2}(PiPr3]2BF4 (6). The molecular structure of 6 has been determined by the X-ray investigation. 6 crystallizes in the monoclinic space group C2/m with a = 16.399(2) angstrom, b = 14.870(5) angstrom, c = 16.855(3) angstrom, beta = 105.98(2)-degrees, and Z = 4. The coordination geometry around the ruthenium atom could be described as based on a distorted octahedron with the two phosphine ligands occupying relative trans positions. The perpendicular coordination plane is formed by the atoms of the vinyl ester ligand (O and C), the oxygen atom of the acetone molecule, and the carbonyl ligand. The coordinated acetone molecule of 6 can be displaced by anions such as [PhC=C]- and Cl- to give the complexes [Ru(C2Ph){C(=CHPh)OH(O)CH3}(CO)(PiPr3)2] (9) and [Ru{C(=CHPh)OH(O)CH3}Cl(C))(PiPr3)2] (10), respectively. 9 reacts with HBF4 in acetone as solvent to give 6 and phenylacetylene. The reaction of 10 with HBF4 leads to the carbene cationic complex [RuCl{=C(CH2Ph)OC(O)CH3)(CO)(PiPr3)2]BF4(11). 10 also reacts with CH3CO2H; in this case the reaction affords cis-PhCH=CHOC(O)CH3 and [RuCl{eta1-OC-(O)CH3}(CO)2(PiPr3)2] (12). The compound [Ru(eta2-O2CCH3)(CO)2(PiPr3)2]BF4 (13) and cis-PhCH=CHOC(O)CH3 were similarly obtained from 6 and CH3CO2H. The reactivity of the six-coordinate bis(alkynyl) complexes [Ru(C2Ph)2(CO)(NCCH3)(PiPr3)2] (14) and [Ru(C2Ph)2-(CO)2(PiPr3)2] (15) toward HBF4 was also investigated. These compounds react in coordinating solvents with HBF4 to give [Ru(C2Ph)(CO)(NCCH3)2(PiPr3)2]BF4 (16) or [Ru(C2Ph)(CO)2{eta1-OC(CH3)2}(PiPr3)2BF4 (17) and phenylacetylene. In dichloromethane 17 releases the acetone ligand to give [Ru(C2Ph)(CO)2(PiPr3)2]BF4 (18). Starting from 18 the hexacoordination can be achieved by addition of acetonitrile and carbon monoxide. These reactions lead to [Ru-(C2Ph)(CO)2(NCCH3)(PiPr3)2]BF4 (19) and [Ru(C2Ph)(CO)3(PiPr3)2]BF4 (20). Complexes 16 and 17 react with CH3CO2H to give [Ru{C(=CHPh)OV(O)CH3}(CO)NCCH3)(PiPr3)2]BF3(21) and [Ru{C(C=CHPh)OC(O)CH3}(CO)2(PiPr3)2]BF4 (22), which can be also prepared from 6 by reaction with acetonitrile and carbon monoxide, respectively.