307498-17-5

Upstream product

• 862509-70-4 Os(trimethylsilyl)(methyl)(CO)2(triphenylphosphine)2 
• 79725-76-1 osmium (ethylene)(carbonyl)2(triphenylphosphine)2 

Downstream Products

• 35880-55-8 Os(CO)2(PPh₃)3 
• 54933-53-8 Os(P(C₆H₅)3)2(CO)2HCl 
• 75731-22-5 Os(C(O)CH₃)H(CO)2(P(C₆H₅)3)2 
• 33635-55-1 Os(CO)3(triphenylphosphine)2 

Relevant academic research and scientific papers

Metallacyclic complexes with ortho-silylated triphenylphosphine ligands, LnOs(κ2(Si,P)-SiMe2C6H 4PPh2), derived from thermal reactions of the coordinatively unsaturated trimethylsilyl, methyl complex, Os(SiMe 3)(Me)(CO)(PPh3)2

Reaction between Os(SiCl3)Cl(CO)(PPh3)2 and five equivalents of MeLi produces a colourless intermediate, tentatively formulated as the lithium salt of the six-coordinate, dimethyl, trimethylsilyl-containing complex anion, Li[Os(SiMe3)(Me) 2(CO)(PPh3)2]. Reaction of this material with ethanol releases methane and gives the red, coordinatively unsaturated methyl, trimethylsilyl-containing complex, Os(SiMe3)(Me)(CO)(PPh 3)2 (1). An alternative synthesis of 1 is to add one equivalent of MeLi to Os(SiMe3)Cl(CO)(PPh3)2, which in turn is obtained by adding three equivalents of MeLi to Os(SiCl 3)Cl(CO)(PPh3)2. Treatment of 1 with p-tolyl lithium, again gives a colourless intermediate which may be Li[Os(SiMe 3)(Me)(p-tolyl)(CO)(PPh3)2], and reaction with ethanol gives the red complex, Os(SiMe3)(p-tolyl)(CO)(PPh 3)2 (3). Complexes 1 and 3 are readily carbonylated to Os(SiMe3)(Me)(CO)2(PPh3)2 (2) and Os(SiMe3)(p-tolyl)(CO)2(PPh3)2 (4), respectively. Heating Os(SiMe3)Cl(CO)(PPh3)2 in molten triphenylphosphine results only in loss of the trimethylsilyl ligand and formation of the previously known complex containing an ortho-metallated triphenylphosphine ligand, Os(κ2(C,P)-C6H 4PPh2)Cl(CO)(PPh3)2. In contrast, heating the five-coordinate osmium-methyl complex, Os(SiMe3)(Me)(CO) (PPh3)2 (1), in the presence of triphenylphosphine results mainly, not in tetramethylsilane elimination, but in ortho-silylation as well as ortho-metallation of different triphenylphosphine ligands giving, Os(κ2(Si,P)-SiMe2C6H4PPh 2)(κ2(C,P)-C6H4PPh 2)(CO)(PPh3) (5). A byproduct of this reaction is the non-silicon containing di-ortho-metallated complex, Os(κ2(C,P)- C6H4PPh2)2(CO)(PPh3) (6). A similar reaction occurs when Os(SiMe3)(Me)(CO)(PPh 3)2 (1) is heated in the presence of tri(N-pyrrolyl) phosphine producing Os(κ2(Si,P)-SiMe2C 6H4PPh2)(κ2(C,P)-C 6H4PPh2)(CO)[P(NC4H 4)3] (7) but a better synthesis of 7 is to treat 5 directly with tri(N-pyrrolyl)phosphine. Heating the six-coordinate complex, Os(SiMe3)(Me)(CO)2(PPh3)2 (2), gives two complexes both containing ortho-metallated triphenylphosphine, one with loss of the trimethylsilyl ligand, giving the known complex, Os(κ2(C,P)-C6H4PPh2)H(CO) 2(PPh3), and the other with retention of the trimethylsilyl ligand, giving Os(SiMe3)(κ2(C,P)- C6H4PPh2)(CO)2(PPh3) (8). Crystal structure determinations for 5, 6, 7 and 8 have been obtained.

SYNTHESIS, STRUCTURE AND REACTIONS OF A dihapto-FORMALDEHYDE COMPLEX, Os(η2-CH2O)(CO)2(PPh3)2

Os(η2-CH2O)(CO)2(PPh3)2 results from direct reaction of formaldehyde with the zerovalent complex, Os(CO)2(PPh3)3.The structure of Os(η2-CH2O)(CO)2(PPh3)2 was determined by X-ray crystallography.The crystals are triclinic, space group P, a 18.739(2), b 11.157(1), c 9.986(1) Angstroem, α 116.70(1), β 93.20(1), γ 107.93(1) deg, V 1727.69 Angstroem3, Z = 2, Dm 1.55(2), Dc 1.57 g cm-3.Refinement of atomic parameters was by full-matrix least-squares methods, employing anisotropic thermal parameters for all non-hydrogen atoms except for the carbon atomsof the phenyl rings.The formaldehyde hydrogen atoms were located from difference electron density maps, other hydrogens were included in calculated positions.Final residuals were R = 0.047 and Rw = 0.061 for 3508 unique observed reflections measured on an automatic diffractometer.The complex itself is monomeric, although interstices in the crystal lattice are occupied by hydrogen-bonded water dimers which fulfil a purely space-filling role.The osmium is bonded to two mutually trans triphenylphosphines, two carbonyls, and the η2-formaldehyde, in an arrangement which is best described as distorted octahedral.The geometry of the coordinated formaldehyde is characterised by Os-O 2.039(7), Os-C 2.186(8) and C-O 1.584 (11) Angstroem.The Os-P bonds are equivalent at 2.372(2) and 2.378(2) Angstroem but the Os-CO bond trans to the formaldehyde carbon 1.931(7) Angstroem is longer than that trans to the formaldehyde oxygen 1.907(7) Angstroem.Os(η2-CH2O)(CO)2(PPh3)3 has proved to be a useful synthetic precursor for stable formyl, hydroxymethyl, methoxymethyl, and halomethyl (CH2X, X = Cl, Br, I) complexes.The compoundsOs(CHO)H(CO)2(PPh3)2, Os(CH2OH)H(CO)2(PPh3)2, Os(CH2OMe)Cl(CO)2(PPh3)2 and Os(CH2Cl)Cl(CO)2(PPh3)2 are illustrative of the many compounds which have been characterised.A general synthetic route to neutral formyl osmium complexes, Os(CHO)X(CO)2(PPh3)2 (X = halide or alkyl) has been developed from reaction of the cations + with BH4-.Acetaldehyde also reacts with Os(CO)2(PPh3)3 forming Os(η1-CCH3)H(CO)2(PPh3)2.No reaction was observed with benzaldehyde, and trichloroacetaldehyde affords the cation, +.