2022 Volume 61 Issue 3 Pages 194-199
We have reported drastic enhancement of photoluminescence of chiral Eu(III) complex (Eu(D-facam)3) in 1-butanol by cooperating effect of tetramethylammonium cation with specific counter anions of chloride and acetate. In this study, based on such unusual luminescence improvement, solvent effect of this luminescence enhancement was further investigated by comparing a series of primary alcohols with straight alkyl chains (carbon number, n : 1∼6) including methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol and 1-hexanol. In the case of both anions, notable alcoholic solvent effect on luminescence properties of Eu(D-facam)3 were observed upon coexistence with tetramethylammonium citation. Interestingly, in 1-pentanol, Eu(D-facam)3 achieved a superior luminescence enhancement above 500 times and induced circular polarized luminescence (glum=-0.69) by the interaction with tetramethylammonium acetate. On the contrary, the luminescence of Eu(D-facam)3 decreased by addition of tetramethylammonium acetate the in the methanol. The unusual optical behavior would be attributed to structural change of Eu(D-facam)3 induced by the interaction of tetramethylammonium and specific anions in alcoholic solution. The strength of their interactions would be affected by polarity of the alcoholic solvents, leading to huge dependence of the luminescence intensity on the alcohol species.
