Table 1.

Solvatochromic properties of probes 1–5.

Compound	Solvent	λabs [nm]	ε [M−1 cm−1]	λem [nm]	Stokes Shift [cm−1 (nm)]	QY a
1	Dioxane	300	17,430	482	12,586 (182)	0.10
	DMF	288	16,280	480	13,889 (192)	0.13
	Ethyl Acetate	302	12,980	480	12,279 (178)	0.14
	Methanol	293	12,770	481	13,340 (188)	0.13
	THF	301	10,580	479	12,346 (178)	0.17
	Toluene	305	12,315	482	12,040 (177)	0.20
2	Dioxane	377	29,066	488	6033 (111)	0.11
	DMF	379	26,470	479	5508 (100)	0.08
	Ethyl Acetate	375	30,205	484	6006 (109)	0.08
	Methanol	370	23,960	474	5930 (104)	0.10
	THF	379	23,910	484	5724 (105)	0.11
	Toluene	382	23,810	486	5602 (104)	0.12
3	Dioxane	376	23,760	483	5892 (107)	0.13
	DMF	377	17,430	471	5294 (94)	0.12
	Ethyl Acetate	375	22,130	478	5746 (103)	0.11
	Methanol	368	16,305	464	5622 (96)	0.08
	THF	374	13,180	470	5461 (96)	0.09
	Toluene	378	16,820	480	5622 (102)	0.18
4	Dioxane	380	33,950	478	5395 (98)	0.29
	DMF	384	28,660	451	3869 (67)	0.17
	Ethyl Acetate	379	33,795	472	5199 (93)	0.24
	Methanol	369	27,475	460	5361 (93)	0.15
	THF	384	30,248	482	5295 (98)	0.26
	Toluene	383	28,922	470	4833 (87)	0.38
5	Dioxane	322	28,980	460	9317 (138)	0.13
	DMF	322	19,240	461	9364 (139)	0.18
	Ethyl Acetate	326	24,707	459	8888 (133)	0.16
	Methanol	313	18,270	457	10,067 (144)	0.16
	THF	319	18,138	460	9609 (141)	0.19
	Toluene	325	20,745	461	9077 (136)	0.17

All photophysical values reflect the average of three independent measurements. ^a Φ_F was measured referring to Quinine sulfate as standard (Φ_F = 0.546 in H₂SO₄ 0.5 M, λ_ex 366 nm).