Electronic Structure, Reactivity, and Some Physical Properties

Electronic Structure, Reactivity, and some Physical Properties 

Analogues of Monocyclic Hydrocarbons 1. Parent Skeleton An Alternant Hydrocarbon 

28 All HMO calculations for three- and four-membered rings can be considered at best only roughly informative because with these substances one of the assumptions of the HMO method is not fulfilled, namely negligible a—ir interaction. 

The first quantum chemical study of thiophene was due to Wheland and Pauling29 who used a model neglecting d-orbital participation and demonstrated that the inductive effect must be allowed for in order to explain its chemical reactivity. Valence-bond12(VB) (cf. ref. 29a) and free-electron (FE) treatments30 followed. A novel approach was devised by Longuet-Higgins13 who studied a model in which the 

Kleinert, S. Richter, and K. Gewald, Angew. Ghem. 74, 118 

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II. Electronic Structure, Reactivity, and Some Physical Properties 14... 

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