212250-49-2Relevant academic research and scientific papers
Oxo ligands as assembling units in mixed-metal cluster chemistry: Synthesis and X-ray structure of the bow-tie cluster [Mo2Ru3(μ3-O)2(μ3-CPh)(μ-C3Ph3)(CO)8(η-C5H5)2]
Adams, Harry,Gill, Louise J.,Morris, Michael J.
, p. 117 - 123 (1997)
The thermal reaction of [Mo2(O)(μ-O)(μ-C4Ph4)(η-C5H5)2] with [Ru3(CO)12] gives the pentanuclear cluster [Mo2Ru3(μ3-O)2(μ3-CPh)(μ-C3Ph3)(CO)8(η-C5H5)2], which has been crystallographically characterised. The compound displays several unusual features: (i) a highly distorted bow-tie structure in which the two metal triangles are virtually perpendicular; (ii) the cleavage of the initial four carbon chain into a dimetalla-allyl fragment and an alkylidyne group; (iii) the presence of two triply-bridging oxo ligands; and (iv) the coordination of one of the phenyl groups of the C3Ph3 ligand to ruthenium.
The Sequential Linking of Alkynes at Dichromium and Dimolybdenum Centres; X-Ray Crystal Structure of
Knox, Selby A. R.,Stansfield, Robert F. D.,Stone, F. Gordon A.,Winter, Mark J.,Woodward, Peter
, p. 173 - 186 (2007/10/02)
In heptane at reflux, the alkynes RCCR (R=Ph, H, or CO2ME) react with to give complexes .An X-ray diffraction study on the product from PhCCPh shows that the crystals of when grown from dichloromethane-hexane incorporate 1/4CH2Cl2 per molecule of complex and are orthorombic, with Z=8 in a unit cell of dimensions a=19.569(4), b=19.731(5), c=16.637(2) Angstroem, and space group Pbcn (no. 60).The structure has been solved by heavy-atom methods from 3166 data for which I>/=3.0?(I), collected on a four-circle diffractometer, and refined to R 0.066.The axis of the molecule comprises a (η-C5H5)CrCr(η-C5H5) moiety which is non-linear, with the cyclopentadienyl ring in an unsymmetrical trans relationship to one another, and with a carbonyl ligand semi-bridging in a plane which is effectively a mirror plane for the whole molecule.Two PhCCPh molecules have joined to form a four-carbon chain, of which the two terminal atoms form a quasi-tetrahedral group with the two chromium atoms Cr 2.337(2), Cr-C 2.025(7) mean, C...C(non bonded) ca. 2.7 Angstroem>, and the two central atoms are ?-bonded to that Cr atom which does not carry the carbonyl ligand.The two metal atoms lie on opposite sides of the plane through the four-carbon portion of the CrC4Ph4 ring.The alkynes RCCH (R=Ph or Me) react with to yield as a major products the complexes in which there is a head-to-tail arrangement of the Ph or Me groups in the C4Cr rings.However, with phenylacetylene the isomer containing the ring system was also detected.The compounds (n=4 or 6) react with PhCCPh in octane at reflux to give affords , a 'fly-over' complex containing a six-carbon chain bridging a MoMo bond.Reaction of with RCCR (R=CO2Me) yields the complexes (two isomer) and (two isomers) in which C6 and C8 chains bridge Mo-Mo bonds respectively.The structures of these species were deduced from 1H and 13C n.m.r. spectra.Reaction of with RCCR (R=CO2Me) gives and (two isomers), characterised inter alia by their 1H and 13C n.m.r. spectra.Treatment of with MeO2CCCCO2Me gives two isomers of composition , thereby establishing that the complexes with four linearly linked alkynes are formed from the species with three such linked groups.Possible mechanisms for carbon-chain growth on the dichromium and dimolybdenum centres are discussed and are related to the changes in multiplicities of the metal-metal bonds.
