Octupolar dendrimers with large first hyperpolarizability

A series of 1,3,5-tricyano-2,4,6-tris(styryl)benzene derivatives (1,2) and dendrimers (3) have been synthesized and their first hyperpolarizabilities (β) were determined. Whereas the λ_max values of 1-3 are similar, the oscillator strength increases with the molecular size. For all compounds, the Stokes shifts are significantly larger when NAr₂ is used as the donor. The β(0) values of 1-3 range from 252 to 507 × 10^-30 esu and increases with the number of octupolar units in the molecule. When the octupolar molecules are linked to the 1,3,5-position of the benzene ring by flexible ether linkages, the β(0) value increases by 1.7 fold. On the other hand, octupolar monodendron based on the nitrogen atom core and 1,3,5-tricyano-2,4,6-tris(p-diarylaminostyryl)benzene moieties at the periphery exhibits β(0) = 507 × 10^-30 esu, which is one of the largest β(0) values reported for the octupolar molecules.