Solution Spectra and Oscillator Strengths of Electronic Transitions of Pyridine and Some Monosubstituted Derivatives

Abstract

The near ultraviolet absorption spectra of the following substances have been measured in iso‐octane and ethyl alcohol solutions: pyridine, the isomeric picolines, 2‐ and 3‐fluoropyridine, 2‐ and 3‐chloropyridine, and 2‐ and 3‐bromopyridine. Solvent effects were observed and oscillator strengths were measured for the singlet‐singlet π—π^* and n—π^* electronic transitions which occur in the spectral region 34 000 cm^‐1 to 48 000 cm^‐1. It was found that in this spectral region the n—π^* transition is missing in the case of 2‐fluoro‐, 2‐chloro‐ and 2‐bromopyridine.