The application of the McLachlan approximation to π-electron open-shell crystal orbital calculations on columnar stacks of macrocyclic radical ions

Abstract

The criterion of Katz et al., for the minimum required velocity for charge carriers in a band has been used to identify those columnar stacks of radical ions to which the band model is applicable in the context of extrinsic semiconduction. The open-shell π-electron crystal orbital methods used are those of Ladik and of Honeybourne, the latter method being presented herein. On the basis of the width of the band housing the odd α-electron (and the consequent charge carrier velocity) the band model is applicable to the majority of radical cations studied and to the radical anions of compounds [5, 14]-dihydrodibenzo [b, i] [1, 4, 5, 8, 9, 11, 12, 14] octaaza cyclotetradecine and tetrabenzo [b, f, j, n] [1, 5, 9, 13] tetraaza cyclohexadecine at an interplanar separation of 0·373 nm. At a separation of 0·336 nm, the band model is applicable to all twenty two pseudo-linear, perfectly columnar stacks of macrocyclic radical ions.