The Preparation of All para-Polyphenyls with Increased Solubility and Enhanced Third Order NLO Activity

A series of all para-polyphenyenes up to heptaphenyl were prepared with solubilizing n-decyloxy pendants. The n-alkoxy pendants allow solubility in tetrahydrofuran for evaluation by femtosecond degenerate four-wave mixing. The physical, chemical, and electro-optical measurements are summarized. The oligomers corresponding to monomer and trimer have increased second hyperpolarizability due to purely extended pi-conjugation effects. However, the pentamer and heptamer evaluations indicated large increases in hyperpolarizability which were not solely attributable to conjugation increases. Furthermore, two-photon resonance enhancement was confirmed in the heptamer by an upconverted blue emission of the heptamer solution at 602nm. Two photon resonance was suspected in the pentamer because of less intense blue emission. Nonlinear optical materials, Degenerate four-wave mixing, Polyphenyls, Materials, Polymers