Charge transfer and other donor---acceptor PLC complexes

5 CHARGE TRANSFER AND OTHER DONOR-ACCEPTOR PLC COMPLEXES 

Molecular recognition processes may also involve charge transfer or, more generally, donor-acceptor interactions. In covalently based PLCs, they have been used, for instance, to enhance mesomorphic stability and even induce mesophases, when copolymers containing separate electron donor and electron acceptor pendant chains are prepared [63 -68] or when blends of the respective homopolymers are prepared [68-70]. 

Complexes of ((17a) or (17b)) + (20), where the small molecule is ionic in character as well as being an electron acceptor, were also investigated [74]. It was found that complexes with Cl as a counterion lead to phase separation, whereas those with Br and I usually give miscible systems. Significantly, most of the miscible complexes are 

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