On the calculated first hyperpolarizability of substituted tri-cyclohexadien-2-yl-amines: Novel targets for experimental research

A new class of molecules, consisting of substituted cyclohexadien-2-yl-amines, is proposed as candidates for new materials with non-linear optical properties. The first hyperpolarizability tensor components for these molecules are calculated at the CPHF/6-31G**++, CPDFT/B3LYP/6-31G**++ and CPDFT/X3LYP/6-31G**++ levels. The results are analyzed in terms of the partition of the tensor into its dipolar and octupolar components. The molecules present calculated β components with values comparable to those of p-nitro-aniline, but with structural features that should result in materials with more than one axis of optical activity, and without the common pitfall of classic push-pull molecules, namely, the tendency to form centro-symmetric crystals. Calculated EFISH values, for future comparison with experimental data, are also presented.