Preferential solvation of a β-sensitive dye in binary mixtures of a non-protic and a hydroxylic solvent

The preferential solvation of the solvatochromic dye N,N, N′,N′-tetramethylethylenediaminoacetyl-acetonatocopper(II) perchlorate (1), [Cu(tmen)(aca)]ClO–4, in binary solvent mixtures comprising one hydroxylic component (water, methanol, ethanol or propan-2-ol) and a non-protic co-solvent (acetone, acetonitrile or dimethylformamide) is discussed and interpreted in terms of hydrogen-bonding effects which alter the ‘intrinsic’ electron-donating ability of the hydroxylic solvent.