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Theoretical analysis of K ‐region and bay‐region indicators of carcinogenicity
Author(s) -
Lowe John P.
Publication year - 1982
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560220607
Subject(s) - carbocation , chemistry , bay , delocalized electron , ring (chemistry) , benzene , stereochemistry , computational chemistry , photochemistry , organic chemistry , civil engineering , engineering
The correlation of the K ‐region carcinogenicity indices of Pullman and of Mainster and Memory with bay‐region carbocation delocalization energy ( BCDE ) is displayed and shown to be maintained at the perturbational molecular orbital ( PMO ) level. PMO algebraic relations are examined to reveal the underlying relationships. Some correlation between BCDE and K ‐region indices exists simply because carbocation formation occurs preferentially on carbons which are bonded to positions α (adjacent) to ring fusion centers. Sampling a K region is synonymous with sampling such α carbons. However PMO analysis shows that a very strong correlation exists between BCDE and indices for a certain type of K region (called “primitive”). It is further shown that high BCDE is favored by a straight‐line chain of benzene rings as one moves away from the bay region. Kinks in the chain will lower the BCDE , and the closer the kink is to the bay region, the greater is its effect. Effects of methylation upon BCDE are shown to correlate with K ‐region indices if the methylation occurs at a carbon which is in the opposite class as the carbon to which the bay‐region carbocation is attached.