Author:
Brown RD,Burden FR,Mohay GM
Abstract
A study is made of the
polarities predicted for alternant hydrocarbons by the VESCF procedure with
non-neighbour resonance integrals included. Four categories of unsymmetrical
hydrocarbons emerge: purely cyclic six-membered ring compounds (μ ≤
0.1 D), systems containing conjugated chains (μ = 0.1 D), quinodimethanes (μ = 0.3 D), systems containing
four-membered rings (μ = 0.6 D or more). The theoretical values are close
to experiment in the few cases where the latter is available but the need for
further precise experimental studies is emphasized. For comparison, analogous
calculations on non-alternant hydrocarbons are presented. The results suggest
that alternants containing four-membered rings are as polar as typical
non-alternants and that on polarity grounds there is no clear-cut separation
into two categories of hydrocarbon. The discrepancy between
theory and experiment for azulene and possible discrepancies for one or
two other non-alternants 1s discussed. It seems possible that the neglect of
possible σ-bond polarities should be questioned and that recent
theoretical techniques embracing all valence electrons might be needed for full
understanding of hydrocarbon polarities.
Cited by
7 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献