Optical properties of bis-(2,4,6-trimethylpyridine)iodine(I) cation: absorption and emission

摘要

With regard to its electronic structure, the cation Icolla_2~+ (coll = collidine or 2,4,6-trimethylpyridine) is viewed as a coordination compound of iodine(I) with a p~4 electron configuration. The lowest-energy excited state of Icoll_2~+ is suggested to be a pipi~* collidine intraligand (IL) triplet which appears in absorption (lambda_max = 332 nm, epsilon = max = 405 nm, phi = 0.001, tau approx 90 ns). Owing to the heavy-atom effect of iodine this phosphorescence occurs at r.t. The longest-wavelength pp absorption is apparently obscured by the intense spin-allowed IL band at lambda_max = 268 nm.