The Barrier to Internal Rotation and Electronic Effects in para-Halogenophenols: Theoretical Study
1.
SYSNO ASEP
0101128
Document Type
J - Journal Article
R&D Document Type
Journal Article
Subsidiary J
Ostatní články
Title
The Barrier to Internal Rotation and Electronic Effects in para-Halogenophenols: Theoretical Study
Title
Bariéra vnitřní rotace a elektronické efekty v para-halogenfenolech: teoretická studie
Author(s)
Zierkiewicz, W. (PL) Michalska, D. (PL) Hobza, Pavel (UFCH-W)
Source Title
Chemical Physics Letters. - : Elsevier
- ISSN 0009-2614
Roč. 386, 1/3 (2004), s. 95-100
Number of pages
6 s.
Language
eng - English
Country
NL - Netherlands
Keywords
barrier height ; halogenophenols ; natural bond analysis
Subject RIV
CF - Physical ; Theoretical Chemistry
R&D Projects
LN00A032 GA MŠMT - Ministry of Education, Youth and Sports (MEYS)
CEZ
AV0Z4040901 - UFCH-W
Annotation
The OH rotational barrier height in phenol and para-halogenophenols systematically decreases in the series Br, Cl and F, while the changes in the CO bond length and CO bond strength do not follow this order. On the basis of the NBO analysis it is suggested that lowering of the barrier height in p-halogenophenols is caused by the decrease of electron density in the sigma antibonding orbital, sigma*(CO), and a weak occupancy of this orbital is due to the electron delocalization from the sigma(CC) ring orbitals. This effect can be either reinforced or reduced, depending on the extent of conjugation between the p(z)-type lone electron pair on the oxygen atom and the pi*(CC) acceptor orbitals in the aromatic ring.
