Abstract
The charge‐transfer absorption of 12 aromatic‐hydrocarbon—TCNE molecular complexes in polymer matrices has been studied in the 0–25‐kbar range. The observations for these solid solutions are compared with the results for compressed liquid solutions obtained by Gott and Maisch. The spectral shifts in the charge‐transfer‐band maxima range between +540 and −1700 cm−1 at 25 kbar for the complexes containing the various donors. A 1.1–3.5‐fold increase in intensity at 25 kbar can be related directly to electronic transition strengths without applying corrections for complexation equilibria as required in liquid solutions. The bandwidths of the charge‐transfer bands appear insensitive to compression. A comparison of the pressure influence on the spectral characteristics of molecular complexes and of the free donors suggests that for complexes the effects from solvent interactions are overshadowed by strong charge‐transfer forces which are highly specific in nature.