EXCIPLEX FORMATION BY ANTHRACENE MONOSULPHONATES IN AQUEOUS-SOLUTION AND THE ROLE OF NONAQUEOUS SOLVENTS

The absorption 2nd fluorescence spectra of anthracene-1-sulphonate (1- AS), anthracene-2-sulphonate (2-AS), anthracene-1,5-disulphonate (1,5- AS) and anthracene-1,8-disulphonate (1,8-AS). have been studied in a s eries of polar, protic and aprotic solvents. For monosulphonates the a bsorption spectra are not much modified in different solvents but emis sion spectra present a structureless feature in aqueous solution. In n onaqueous solvents vibrational peaks are evident and intensities of fl uorescence maxima decrease with blue shift. The disulphonates show nor mal behaviour. When nonaqueous solvents are gradually added to the aqu eous solutions of nonosulphonates, vibrational features gradually deve lop in the fluorescence spectra passing through an isosbestic point. B y suitable treatment of data it has been established that the monosulp honates form weak exciplexes with water clusters.