Reactions of Co-ordinated Ligands. Part 32. The Reaction of Sulphur Nucleophiles with Cationic Molybdenum Alkyne Complexes: Alkyne Rotation and the Molecular Structures of the Complexes (η2-MeC2Me)(η-C5H5)> and 2-MeC2Me)(η-C5H5)>
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Source and publish data:
Journal of the Chemical Society, Dalton Transactions p. 2747 - 2756 (1984)
Update date:2022-08-03
Topics:
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Authors:
Allen, Stephen R.
Glauert, Timothy H.
Green, Michael
Mead, Kevin A.
Norman, Nicholas C.
et al.
Article abstract of DOI:10.1039/DT9840002747
Treatment of 2(η2-MeC2Me)(η-C5H5)> with NaSR (R = Me, p-NH2C6H4, p-MeOC6H4, p-MeC6H4, C6H5, or p-NO2C6H4) leads to displacement of P(OMe)3 and formation of (η2-MeC2Me)(η-C5H5)>.Similar reactions afforded (η2-MeC2Me)(η-C5H5)> and (η2-ButC2H)(η-C5H5)>.Barriers to rotation of the but-2-yne ligand present in these complexes are related to electronic effects of the substituents on the thiolate ligand.The molecular structure of (η2-MeC2Me)(η-C5H5)> has been established by single-crystal X-ray crystallography.Crystals are monoclinic, space group P21/n with a = 8.968(3), b = 20.104(9), c = 11.452(5) Angstroem, β = 95.77(3), and Z = 4.Using 3601 reflections measured on a four-circle diffractometer at 200 deg K, the structure has been refined to R 0.028, R' 0.032.The molecule adopts the familiar three-legged piano stool geometry, in which the but-2-yne ligand is orientated such that the central C-C bond lies approximately parallel to the Mo-P vector.In contrast, 2-MeC2Me)2(η-C5H5)> reacts with NaSMe to give the complexes 2-MeC2Me)(η-C5H5)> and , whereas the corresponding reaction with 2-MeC2Me)2(η-C5H5)> affords 2-MeC2Me)(η-C5H5)>.Reaction of sodium dimethyldithiocarbamate with 1C2R2)2(η-C5H5)> (R1 = R2 = Me or R1 = But, R2 = H) gives the monoalkyne complexes 2-R1C2R2)(η-C5H5)>.In contrast the anion (1-) affords a separable mixture of 2-R1C2R2)2(η-C5H5)> and .Reaction of the S,S'-bidentate species with carbon monoxide gives 2-MeC2Me)(η-C5H5)>, which was structurally identified by X-ray crystallography.Crystals are orthorhombic, space group P212121 (no. 19) with Z = 4 in a unit cell of dimensions a = 9.852(3), b = 11.486(4), and c = 18.476(6) Angstroem.From 1714 independent intensities measured at 292 deg K the structure has been refined to R 0.059, R' 0.041.The molecule adopts a piano stool geometry with the but-2-yne lying parallel to the Mo-CO vector.The dithioaryl ligand is monodentate.
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Full text of DOI:10.1039/DT9840002747