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Durham e-Theses
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Preparative studies of alkoxy derivatives of manganese carbonyl

Bell, Gillian (1988) Preparative studies of alkoxy derivatives of manganese carbonyl. Masters thesis, Durham University.



Oligomeric alkoxy derivatives of bromopentacarbonyl manganese (I) and bromotetracarbonylmanganese (^+) (I) were prepared by reaction with a base and a variety of alcohols. The nature of the products, their structural and bonding features are discussed in the context of alkoxide chemistry in general. Reactions of Mn(CO)(_5)Br with triethylamine and alcohols in hydrocarbon solvents at 55ºC were monitored by IR spectroscopy which indicated the formation of one major product, either a Mn(_3)(CO)(_g)(OR)(_3) or a Mn(_4)(CO)(_12)(OR)(_4) complex. Yields were non-reproducible and isolated solids were shown to be a mixture of products. Mass spectral data indicated oligomers of the type [Mn (CO) (_3) (OR) ] (_n), where n = 3 to 6, and dimers of formula [Mn(CO) (_4) (OR)] (_2). Reliable yields were obtained using sodium carbonate as the base and acetone as the solvent. The products are mixtures and mass spectral data shows a predominance of trimeric alkoxy derivatives, although products with n = 4 to 6 and dimers were also found. A monomer was obtained with triphenylcarbinol, Mn(CO)(_5)(OCPh(_3)).The results of the reactions of Mn(CO)(_4)(PPh(_3))Br with triethylamine and alcohols in hydrocarbon solvents are more difficult to interpret. Mixtures of products are obtained, dimeric alkoxy derivatives [Mn(CO)(_3)(PPh(_3)) OR](_2) predominating. However, non-alkoxy complexes appear to be the major products in a number of cases. A 1.2ppm shift in the d(_6)-acetone (^1)H NMR spectrum of the methoxy complex [Mn(CO) (_3) (OM(^6)e) ] (_n) was attributed to paramagnetic species of the type [Mn (OMe) (_2) ] (_n). These paramagnetic compounds may well be present in other product mixtures. Attempted purification techniques and methods of separation of the product mixtures are also discussed.

Item Type:Thesis (Masters)
Award:Master of Science
Thesis Date:1988
Copyright:Copyright of this thesis is held by the author
Deposited On:08 Feb 2013 13:37

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