Document Detail

Enhanced acidity of cyclopenta-2,4-dienylborane and its Al and Ga analogues. The role of aromatization.
MedLine Citation:
PMID:  20449020     Owner:  NLM     Status:  MEDLINE    
The intrinsic acidity of cyclopenta-2,4-dienylborane and its Al and Ga analogues has been compared to that of cyclopentadiene by means of B3LYP/6-311+G(3df,2p)//CCSD/6-311+G(d,p) calculations. Substitution of one of the H atoms of the C(sp(3))H(2) group of cyclopentadiene by an XH(2) (X = B, Al, Ga) leads to an acidity enhancement which is significantly large for the boron derivative (95 kJ mol(-1)); but much smaller for the Al and Ga containing analogues. This acidity enhancement reflects the stabilization of the anion, in the substituted derivatives, due to a significant reinforcement of the C-X bond. This enhancement is however smaller than expected because, although XH(2) (X = B, Al, Ga) substitution leads to a significant aromatization of the neutral compounds, the aromaticity significantly decreases upon deprotonation, whereas for the unsubstituted parent compound is the other way around. Cyclopenta-2,4-dienylborane and its Al and Ga analogues behave as highly fluxional systems.
Marcela Hurtado; Manuel Yáñez; Jean-Claude Guillemin
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-07-27
Journal Detail:
Title:  Physical chemistry chemical physics : PCCP     Volume:  11     ISSN:  1463-9084     ISO Abbreviation:  Phys Chem Chem Phys     Publication Date:  2009 Oct 
Date Detail:
Created Date:  2010-05-07     Completed Date:  2010-08-09     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100888160     Medline TA:  Phys Chem Chem Phys     Country:  England    
Other Details:
Languages:  eng     Pagination:  8759-66     Citation Subset:  IM    
Departamento de Química, C-9. Universidad Autónoma de Madrid, Cantoblanco, 28049-Madrid, Spain.
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MeSH Terms
Acids / chemistry*
Aluminum / chemistry*
Computer Simulation
Cyclopentanes / chemistry*
Gallium / chemistry*
Models, Chemical
Reg. No./Substance:
0/Acids; 0/Cyclopentanes; 0/cyclopenta-2,4-dienylborane; 7429-90-5/Aluminum; 7440-55-3/Gallium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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