Phenyl Substitution Effects on Triplet–Triplet Absorption Spectra: I. Study of 1,3,6,8-Tetraphenylpyrene

Abstract

The triplet–triplet (T–T) absorption spectrum of 1,3,6,8-tetraphenylpyrene (TPP) was measured from 400 to 620 nm. The data obtained are compared with theoretical calculations using the Ruedenberg–Scherr FEMO model. A planar triplet state is evidenced by fine vibrational structure. The T–T quenching rate constant measured (1.3 ± 0.1 × 109 M−1 s−1) is 20% of the expected diffusion-controlled value.