Proton transfer between carbon acids and methoxide: Studies in methanol, the gas phase and by ab initio MO calculations
作者:Heinz F. Koch、Masaaki Mishima、Han Zuilhof
DOI:10.1002/bbpc.19981020341
日期:1998.3
AbstractA detailed mechanism that features hydrogen‐bonded carbanions as well as free carbanions is presented for hydrogen transfer between carbon acids and methoxide ion in methanol. This is refined for several compounds by measuring their gas phase acidities, ΔG kcal/mol: C6H5CH(CF3)2 [335.3]; p‐C6H4CHClCF3 [337.4]; 9‐phenylfluorene [335.6]; C6F5H [349.2]. Ab initio molecular orbital calculations are reported to evaluate the stability of possible intermediates along the reaction pathway from 2‐hydro‐2‐phenyl‐perfluoropropane and methoxide ion to the carbanion and methanol. The intermediate, C6H5C(CF3)2}−. HOCH3, is 6.8 kcal/mol more stable than the separated species, C6H5C(CF3)2}− and CH3OH, and 43.2 kcal/mol more stable than C6H5CH(CF3)2 and −OCH3.
Gas-phase chemistry of the silaformyl anion, HSiO-
作者:Scott Gronert、Richard A. J. O'Hair、Stephen Prodnuk、Detlev Suelzle、Robert Damrauer、Charles H. DePuy
DOI:10.1021/ja00159a016
日期:1990.1
of Hsub 3}SiOsup minus}} in a tandem flowing afterglow selected ion flow tube (FA-SIFT). The chemistry of the silaformyl anion has been studied in detail. Reactions with COsub2}, COS, CSsub2}, SOsub2}, Osub2}, acetic acid, nitromethane, and hexafluorobenzene reveal a rich chemistry. For example, the sailaformyl anion reacts with COsub2} by both an oxidative pathway giving HSiOsub2}sup