Thin films of calixarenes for quadratic nonlinear optics

Organic molecules with π electron systems and asymmetrical charge distribution are interesting tor use in quadratic nonlinear optics. Calix[4]arenes are cyclophanes that consist of four phenol moieties connected by methylene bridges. Functionalization of these phenols allows the combination of four D-π–A units within a single molecule. The increase in the number of D-π-A systems in a calix[4]arene molecule is accompanied by an enhancement of the molecular hyperpolarizability and the dipole moment and by a blue shift of the charge-transfer absorption band. Different substituted calix[4Jarene compounds have been synthesized and examined.