Polarized π‐Electron Systems in a Chemically Generated Electric Field: Second‐Order Nonlinear Optical Properties of Ammonium/Borate Zwitterions

Abstract

Ammonium and borate substituents polarize π-electron systems, which then exhibit internal CT bands in the UV/Vis spectrum. These systems (for example 1) are distinctly more transparent than analogous push–pull-substituted compounds. Since their first-order hyperpolarizabilities are nevertheless similar to push–pull compounds, they are better suited to applications for second harmonic generation.