Abstract

Polydiacetylenes with increased numbers of π-electrons per repeating unit such as those having aromatic rings directly bound to the main chain, or with enlarged polarizability (Fig. 1) must be better candidates for extraordinarily large NLO responses (1). For the materiallization of such structures, it is indispensable to have corresponding diacetylene monomers crystallized in a polymerizable stack, since polydiacetylenes are obtained by topochemical solid-state poly merization (2). In a series of studies on crystal engineering of the polydiacetylenes with directly bound aromatic substituents (Fig. 2) (3), we have found that even donor and acceptor-substituted diphenyldiacetylenes (Fig. 3A) can be crystallized in a polymerizable stack by virtue of intermo1ecular hydrogen-bonds of properly located amide groups (Fig. 2(d)) (4). In this study, the methodolgy has been expanded to the bifunctional diacetylene monomers (Fig. 3B).

© 1988 Optical Society of America