Fluorescent excimer formation by α,ω-diaminoalkanes and related compounds

Abstract

The fluorescence properties of a number of α,ω-diaminoalkanes have been studied in which the amino groups include diethylamino, pyrrolidino, piperidino, and morpholino residues. Intramolecular excimer formation was usually observed when di- and tri-methylene chains separated the amino groups. α,ω-Dimorpholinoalkanes having chain lengths of varying size between the morpholino groups, exhibited fluorescent excimer formation. Owing to the high concentrations employed it could not be ascertained whether the emission was the result of inter- or intra-molecular complex formation. In all cases the excimer fluorescence was considerably red shifted by a change of solvent from cyclohexane to tetrahydrofuran. This solvent dependency leads to the conclusion that amine excimers have some charge-transfer character.