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 λ_max and β(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 β(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 β(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 β(0) is observed in the octupolar oligomers.