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Mass spectral studies of some mixed chromium and manganese tricarbonyl of benzocycloptadienyl derivatives
Citation
Chu, C. K. (2003). Mass spectral studies of some mixed chromium and manganese tricarbonyl of benzocycloptadienyl derivatives. Malaysian Journal of Chemistry, 5(1), 044-047.
Author
Chu, Chit Kay
Abstract
The mass spectral fragmentation patterns of some derivatives containing both [πC6H5]Cr(CO)3 and [π-C5H5]Mn(CO)3 moieties are discussed. In cases where the two groups are joined together by a ketonic CO, the loss of carbon monoxide molecules involves a combination of a three-step and a two-step process. In cases where the phenyl and cyclopentadienyl rings are connected through an alcohol or olefinic group, ring fusion becomes more important, and the stepwise loss of carbon monoxide seems less important. The ions [C6H5Cr]+ and [C5H4Cr]+ are more stable than [C6H5Mn]+ and [C5H4Mn]+; the latter ions are often not observed. The higher abundance of [C6H5COC5H4Cr]+ relative to the ion [C6H5COC5H4Mn]+ not only suggests a higher stability of the former but also that there is significant ‘across rings” metal participation within the fragments; the π-bonding between the rings and Cr being much stronger than those between the rings and Mn. An intermediate bimetallic species must necessarily be formed in order to facilitate the loss of the ketonic CO. A mechanism for the fragmentation is proposed.
Date Issued
2003
Publisher
Malaysian Chemical Society
Journal
Malaysian Journal of Chemistry