Experimental Determination of the First Hyperpolarizability of New Chiral and Achiral Octupolar Tertiary Amines by Hyper-Rayleigh Scattering

Tertiary amines with a fully sp2-hybridized nitrogen as central atom and acceptor-substituted phenyl or diazabiphenyl units as peripheral groups (hereafter shortly referred to as “sidewing-octupoles”) exhibit relatively high β values at short absorption wavelengths. Donor substitution of those sidewings results in a drop in the first hyperpolarizability β at comparable absorption wavelengths. One of the octupoles investigated has three chiral carbon atoms so that it should crystallize in a noncentrosymmetric structure. This is interesting since there is no other way to obtain macroscopic χ(2) structures from octupolar molecules due to the lack of a permanent dipole moment. The first hyperpolarizability β of these octupolar molecules has been measured via the recently developed hyper-Rayleigh-scattering technique (HRS) at 1064 nm.