ABSORPTION, EMISSION AND MASS-SPECTRAL CHARACTERISTICS OF OLIGOTHIOPHENES AND THEIR DERIVATIVES

Oligothiophenes ranging from bithiophene to pentathiophene (1-5) and a number of alkyl and carbonyl derivatives of 1 and 2 have been prepare d and their UV absorption, fluorescence and mass spectra recorded. UV absorption and fluorescence spectra have been recorded in three differ ent solvents and the data used for finding out the influence exerted b y variation in skeletal structure and functional groups, solvents and pH on absorption and emission maxima and intensity. The salient featur es of mass spectra have been discussed. An interesting rearrangement w ith the loss of CO is observed in the case of thenoyl and benzoyl deri vatives. A few daughter ions common to all the oligothiophenes and the ir derivatives, irrespective of the oligomeric size or functional grou ps, are observed. The higher oligothiophenes tend to form fairly abund ant the doubly charged ions.