The reductive activation of [M5C(CO)15] (M = Ru or Os) and subsequent reactions of the dianion [Os5C(CO) 14]2-, carbonylation of [M5C(CO)15] (M = Ru or Os), and the crystal structures of [Os5C(CO) 16], [N(PPh3)2]2[Os 5C(CO)14],...

Brian F.G. Johnson, Jack Lewis, William J.H. Nelson, J. Nicola Nicholls, José Puga, Paul R. Raithby, Maria J. Rosales, Martin Schröder, Maria D. Vargas

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Abstract

Title full:The reductive activation of [M5C(CO)15] (M = Ru or Os) and subsequent reactions of the dianion [Os5C(CO) 14]2-, carbonylation of [M5C(CO)15] (M = Ru or Os), and the crystal structures of [Os5C(CO) 16], [N(PPh3)2]2[Os 5C(CO)14], and [Os5C(CO) 14{Au(PPh3)}2]. High pressure infrared (h.p.i.r.) studies indicate that the cluster [Ru5C(CO)15] (1) adds carbon monoxide under relatively mild conditions (20 °C, 80 atm) to give [Ru5C(CO)16] (2), while under more forcing conditions (90 °C, 80 atm) the cluster (2) reverts back to (1). The osmium analogue, [Os5C(CO)15] (3), gives [Os5C(CO)16] (4) at 70 °C and 50 atm but may be obtained in quantitative yield from an autoclave reaction in the absence of solvent. Complex (4) crystallises in space group P1̄ with a = 10.017(3), b = 15.823(5), c = 16.507(8) Å, α = 96.78(3), β = 103.20(3), γ = 93.41(2)°, and Z = 4. The structure was solved by a combination of direct methods and Fourier-difference techniques and refined by blocked full-matrix least squares to R = 0.073 for 6 120 reflections. The five Os atoms define a 'bridged-butterfly' configuration with a carbide at the centre. There are four terminal carbonyl groups bound to the bridging metal atom and three to each of the other four metal atoms. A h.p.i.r. study of the reaction of (4) with H2 has shown that at a pressure of 75 atm and at temperatures around 90 °C the cluster [Os5H2(C)(CO)15] (5) is produced. The electrochemical or chemical reduction of [M5C(CO) 15] [M = Ru (1) or Os (3)] produces the corresponding dianion [M 5C(CO)14]2- [M = Ru (6) or Os (7)]. An X-ray analysis of the [N(PPh3)2]+ salt of (7) shows that the squarepyramidal Os5C core geometry of (3) is retained. One of the Os-Os bonds in the basal plane is symmetrically bridged by a carbonyl group. The remaining 13 carbonyl ligands are co-ordinated terminally, two each to the carbonyl-bridged metal atoms, and three each to the other three metal atoms. The salt crystallises in space group P1̄ with a = 13.244(6), b = 14.648(9), c = 21.963(14) Å, α = 86.78(5), β = 85.54(5), γ = 81.22(5)°, and Z = 2. The structure was solved using the same techniques as for (4) and refined by blocked-cascade least squares to R = 0.065 for 5 780 observed diffractometer data. The dianion (7) reacts with two equivalents of [Au(PPh3)Cl] to give the neutral complex [Os 5C(CO)14{Au(PPh3)}2] (10) which has also been characterised crystallographically. In (10) the Os5C core shows significant distortions from square-pyramidal geometry. Two opposite Os(basal)-Os(apical) bonds are bridged by the Au atoms of the Au(PPh 3) ligands and these two bonds are significantly longer than the other two unbridged Os(basal)-Os(apical) bonds. Two carbonyl groups are bonded terminally to the apical Os atom, and three each to the four basal Os atoms. This complex crystallises in space group P21/c with a = 20.307(4), b = 9.843(2), c = 27.980(6) Å, β = 100.53(2)°, and Z = 4. The structure was solved and refined as for (7) to R = 0.060 for 7 013 observed diffractometer data.

Original languageEnglish
Pages (from-to)2447-2457
Number of pages11
JournalJournal of the Chemical Society, Dalton Transactions
Issue number11
DOIs
Publication statusPublished - 1983

ASJC Scopus subject areas

  • General Chemistry

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