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Protonation dynamics of ((C/sub 5/H/sub 5/)(CO)Fe)/sub 2/(/mu/-CO)(/mu/-C=CH/sub 2/) and decomposition processes for ((C/sub 5/H/sub 5/)(CO)Fe)/sub 2/(/mu/-CO)(/mu/-C=CH/sub 2/)H/sup +/ in the gas phase

Journal Article · · J. Am. Chem. Soc.; (United States)
DOI:https://doi.org/10.1021/ja00187a015· OSTI ID:5845246

The proton affinity (PA) and site of protonation of ((C/sub 5/H/sub 5/)(CO)Fe)/sub 2/(/mu/-CO)(/mu/-C/double bond/CH/sub 2/) (2), as well as the decomposition processes for ((C/sub 5/H/sub 5/)(CO)Fe/sub 2/(/mu/-CO)(/mu/-C/double bond/CH/sub 2/)H/sup +/ (7), are studied in the gas phase by using Fourier transform mass spectroscopy (FTMS). The PA of 2 is assigned as 232.5 /plus minus/ 2 kcal/mol (relative to PA(NH/sub 3/) = 204.0 kcal/mol) by using the bracketing technique. The site of protonation was determined by labeling studies to be the /beta/-carbon of the /mu/-ethenylidene group of 2 yielding 3 in accord with the known solution chemistry. The decomposition processes for collisionally activated 3 were studied in detail and compared with that for the non-protonated analogue ((C/sub 5/H/sub 5/)(CO)Fe)/sub 2/(/mu/-CO)(/mu/-C/double bond/CH/sub 2/)/sup +/. 3 decomposes by initial elimination of the three carbonyls followed by sequential C/sub 2/H/sub 2/ and H/sub 2/ eliminations yielding respectively ((C/sub 5/H/sub 5/)Fe)/sub 2/H/sup +/ and Fe/sub 2/C/sub 10/H/sub 9//sup +/. Hydrogen migration in the above fragment ions was investigated by monitoring H/D exchange with D/sub 2/ and ethene-d/sub 4/. No exchange occurs for any of the ions ((C/sub 5/H/sub 5/)(CO)Fe)/sub 2/(/mu/-CO)(/mu/-C/double bond/CH/sub 2/)H/sup +/ through ((CC/sub 5/H/sub 5/)Fe)/sub 2/H/sup +/) with D/sub 2/. With ethene-d/sub 4/, one H/D exchange is observed with ((C/sub 5/H/sub 5/)Fe)/sub 2/H/sup +/, with no exchange for any of the larger fragment ions.

Research Organization:
North Dakota State Univ., Fargo (USA)
OSTI ID:
5845246
Journal Information:
J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 111:5; ISSN JACSA
Country of Publication:
United States
Language:
English