Deactivation of excited 4′-dialkylamino-9-styrylacridines

Excited state properties of some 1-(9-anthryl)-2-naphthylethene and 1-(9-anthryl)-2-quinolylethene derivativesDedicated to Professor Frank Wilkinson on the occasion of his retirement.

“…[13][14][15][16][17][18][19][20][21][22][23][24][25][26] While heteroaromatic derivatives of 1,2-diarylethenes 2,27-32 have been widely studied, examples of heteroaromatic 9-APE derivatives are rarely found. 33 In contrast, 1-(9-anthryl)-2-(n-pyridyl)ethenes (n ¼ 2-4, n-APyE, Scheme 1), pyridine derivatives of 9-APE, have been investigated previously. 34 In some of these APE analogs, the photoisomerization mode was observed to change with solvent polarity.…”

Excited state relaxation of 9-(4-diethylaminostyryl)-acridine

“…This form exhibits a considerably higher molar extinction coefficient than the unprotonated counterpart. The validity of the Beer's law, which has been proved at room temperature, shows that in the concentration range of 5·10 −7 to 5·10 −4 M the dye exists in a monomeric form [10]. Neutral molecules show fluorescence with a very large Stokes shift.…”

“…Triplet state formation [11][12][13], excited state reduction [14,15], and relaxation between excited ππ * and nπ * states [11,[16][17][18] were reported for different acridine derivatives. The triplet state formation in some of acridines takes place very efficiently, however, it has already been reported [10] that there is no evidence of triplet state population of DSA dyes. Moreover, triplet state formation as an origin of the about 8 ps dynamics may be eliminated because of strong fluorescence and stimulated emission of molecular species formed during this process.…”