Supersonic jet spectroscopy of N-(4-cyanophenyl)carbazole and its complexes

Abstract

The laser-induced fluorescence spectra of jet-cooled N-(4-cyanophenyl)carbazole (CPC) and its (1 : 1) complexes with various partner species Ar, C₆H₆, C₆H₁₂, CH₃OH, CHCI₃, CH₃CN are presented. With CCI₄, no fluorescent complex was observed. The other 1 : 1 complexes observed gave rise to red-shifted features, which indicates a stabilisation of the S₁ state of the complex relative to its ground state. Inductive and dispersive forces thus play an important role in both non-polar and solvents with small dipole moment and large polarisability. The dipole–dipole interactions involve the dipoles of the polar solvent and CPC in an anti-parallel arrangement. With the exception of CPC–Ar₂, no complexes of higher than 1 : 1 stoichiometry were observed. An attempt was made to produce in the jet the characteristic red-shifted broad emission from the so-called twisted intramolecular charge transfer (TICT) states seen in polar solution. No such emission was observed.