Synthesis and Some Reactions of a Terminal Carbyne Complex of Osmium. Crystal Structures of Os(CR)Cl(CO)(PPh3)2 and Os(=C(AgCl)R)Cl(CO)(PPh3)2

Article abstract of DOI:10.1016/0022-328X(86)80439-9

The reaction of two equivalents of LiR (R=p-tolyl) with the dichlorocarbene complex OsCl2(=CCl2)(CO)(PPh3)2 gives the carbyne complex Os(<*>CR)Cl(CO)(PPh3)2 (I) in good yield.X-ray crystal structure determination shows that I is mononuclear with an Os<*>C distance of 1.78(2) Angstroem.The Os<*>C bond reacts with electrophiles rather than nucleopiles.Thus, HCl adds to give the alkylidene complex OsCl2(=CHR)(CO)(PPh3)2, Cl2 forms OsCl2(=CClR)(CO)(PPh3)2 and sulphur, selenium and tellurium react to yield to corresponding dihapto-chalcoacyls Os(η²-CR)Cl(CO)(PPh3)2 (X= S, Se, Te).Group Ib metal halides also add to the Os<*>C bond form the adducts Os<(=C>R)Cl(CO)(PPh3)2 (MX= CuI, AgCl, AuCl).The X-ray crystal structure determination of Os<(=C>R)Cl(CO)(PPh3)2 (II) suggest that this complex can be considered as a dimetallacyclopropene derivative.Crystals of I are monoclinic, space group P2₁/n, a 17.030(2), b 12.774(1), c 18.315(3) Angstroem β 107.96 grad, V 3793.2 Angstroem^3, Z= 4, D_m 1.53(1), D_c 1.54.Crystal of II are monoclinic, space group P2₁/n, a 13.021(2), b 23.714(2), c 12.999(2) Angstroem, β 90.556(2) grad, V 4013.7 Angstroem³, Z=4, D_m 1.705(5), D_c 1.695.The structures were solved by conventional heavy-atom methods, and refined by full-matrix least-squares employing anisotropic thermal parameters for all non-hydrogen atoms except for the carbon atoms of phenyl rings.Phenyl hydrogen atoms were included in calculated positions.Final residuals R were 0.040 and 0.037, respectively.