Novel azo octupoles with large first hyperpolarizabilities

Novel two-dimensional octupoles containing azo groups and their oligomers have been synthesized and their first hyperpolarizabilities were determined. The lambda(max) and beta(0) values of azo octupoles are nearly the same regardless of the nature of the bridge or the conjugation length. On the other hand, 1,3,5-tricyano-2,4,6-tris[4-(p-diethylaminostyryl)styryl]benzene has a larger beta(0) value than the corresponding azo analogue probably due to the more efficient conjugation ability of C=C compared with the N=N bond. The beta(0)/MW of the octupoles are larger than the corresponding dipoles, whereas those of the azo octupoles are comparable to the latter. Also, retention of monomeric beta(0) is observed in the octupolar oligomers.