Supramolecular Nonlinearity of Chromophore-Functionalized Poly-L-Tyrosine

Abstract

Nonlinear optical chromophores can be organized as orientationally correlated side groups of polypeptides with a rigid backbone. In such an organization, each chromophore contributes coherently to the second-order nonlinear response of the polymer structure. The synthesis of poly-L-tyrosine, functionalized with the NLO-phores 4-nitroaniline, 2,4-dinitroaniline, 2-cyano-4-nitroaniline and 4-nitro-4′-nitroazobenzene, which is organized in α-helix conformation are presented. Solvatochromic measurements show that the hyperpolarizability of the supramolecular structure is a module factor of 18.7 higher than that of the model chromophore and that conformational organization leads to a strong enhancement of the molecular hyperpolarizability β.

Key Words:

• Nonlinear optics
• chromophore-functionalized poly-L-tyrosine
• solvatochromism