Transition-metal nitrosyl compounds. Part V. Nuclear magnetic resonance temperature-dependence studies on mono- and di-nitrosyl-(dithiocarbamato)-complexes of molybdenum and tungsten
- 1 January 1971
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in J. Chem. Soc. A
- p. 994-999
- https://doi.org/10.1039/j19710000994
Abstract
At 25°C the 1H n.m.r. spectrum of [M(NO)2(S2CNMe2)2](M = Mo or W) is consistent with a rigid cis-octahedral geometry. At higher temperatures (80–140°C) a rapid interconversion of the two types of N-methyl group takes place. The 25°C 1H n.m.r. spectrum of [Mo(NO)(S2CNMe2)3] may be interpreted in terms of a pentagonal bipyramidal structure. At elevated temperatures (60–128°C) interconversion of both the N-methyl groups and the two types of dithiocarbamato-ligands occurs. Possible mechanisms for these interconversions or rearrangements are discussed. The most favourable mechanism for both compounds is probably that involving partial dissociation of a dithiocarbamato-ligand, together with a simultaneous rotation of the N-methyl groups about the C–N bond. ΔG* is about 21 kcal mole–1 for the dinitrosyl complexes, and about 18 kcal mole–1 for the mononitrosyl complex.Keywords
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