Document Detail

The gas-phase acidity of HCP, CH3CP, HCAs, and CH3CAs: an unexpected enhanced acidity of the methyl group.
MedLine Citation:
PMID:  12397593     Owner:  NLM     Status:  PubMed-not-MEDLINE    
The gas-phase acidities of methylidynephosphine, HCtbond;P, ethylidynephosphine, CH(3)Ctbond;P, and ethylidynearsine, CH(3)Ctbond;As, have been measured by means of Fourier Transform Ion Cyclotron Resonance (FTICR) mass spectrometry and calculated at the CCSD(T)/6-311+G(3df,2p)//QCISD/ 6-311+G(df,p) level of theory. An analysis of these results shows that, in contrast to the well-known fact that HCtbond;N is a stronger acid than CH(3)Ctbond;N, CH(3)Ctbond;P and CH(3)Ctbond;As are more acidic than HCtbond;P and HCtbond;As, respectively. The most important consequence of this unexpected effect is that while HCtbond;P and HCtbond;As are found to be weaker acids than HCtbond;N, the opposite trend is found for the corresponding methyl derivatives, the acidity of which increases as CH(3)Ctbond;N<CH(3)Ctbond;P<CH(3)Ctbond;As. Also the effects of deprotonation on the structures and the vibrational frequencies of HCtbond;X and CH(3)Ctbond;X (X=N, P, As) compounds are qualitatively similar, but quantitatively very different for nitrogen- as compared with phosphorus- and arsenic-containing compounds. A rationalization of these differences in terms of the bonding differences is presented.
Otilia Mó; Manuel Yáñez; Jean-Claude Guillemin; El Hassan Riague; Jean-François Gal; Pierre-Charles Maria; Christine Dubin Poliart
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Chemistry (Weinheim an der Bergstrasse, Germany)     Volume:  8     ISSN:  0947-6539     ISO Abbreviation:  Chemistry     Publication Date:  2002 Nov 
Date Detail:
Created Date:  2002-10-24     Completed Date:  2003-07-25     Revised Date:  2009-08-04    
Medline Journal Info:
Nlm Unique ID:  9513783     Medline TA:  Chemistry     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  4919-24     Citation Subset:  -    
Departamento de Química, C-9 Universidad Autónoma de Madrid Cantoblanco, Spain.
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