Table 1.

Spectroscopic data for prodan and derivatives.

Compound	Solvent	λ abs [nm][a]	ϵ max [M−1 cm−1]	λ em [nm][b]	Φ F [c]	τ aver [ns][d]
Prodan[e]	AQ	358	18 127[f]	525	0.19	1.0
	ACN	352	nd	457	0.86	3.4
	Tol	350	18 899	414	0.57	2.1
1	AQ[e]	314	6022[f]	437	0.57	9.3
	ACN[g]	325	nd	424	0.59	7.1
	Tol[g]	325	5500	403	0.66	6.0
2 [h]	AQ[i]	482	20 926[f]	628	0.001	nd[j]
	ACN[k]	424	nd	619	0.02	0.13
	Tol[k]	422	26 060	504	0.55	3.4
3	AQ	375	13 832[f]	528	0.06	0.77
	ACN	360	nd	475	0.67	2.9
	Tol	360	16 080	432	0.74	2.0
4	AQ	350	27 268[f]	523	0.03	0.38
	ACN	348	nd	456	0.71	2.4
	Tol	349	29 419	413	0.71	2.9
5	AQ[e]	356	29 686[f]	599	0.006	0.088
	ACN[g]	367	nd	500	0.98	2.3
	Tol[g]	367	26 057	437	0.97	1.6
6	AQ[e]	341	3522[f]	433	0.005	0.051
	ACN[g]	360	nd	417	0.51	6.6
	Tol[g]	359	3637	404	0.54	5.3

AQ=1 % DMSO in 10 mm phosphate buffer (pH 7.4). ACN=acetonitrile. Tol=toluene. nd=not determined. [a] Wavelength of absorption maximum. [b] Wavelength of emission maximum. [c] Fluorescence quantum yields were determined by taking 1,9‐diphenylanthracene in cyclohexane (Φ _F=0.97) as a reference. [d] Average fluorescence lifetime. See Table S2 of the Supporting Information for complete lifetime data. An excitation wavelength of 377 nm was used for all compounds, with the exception of compound 2, for which an excitation wavelength of 405 nm was used. [e] Excitation wavelength was 350 nm. [f] Due to poor solubility in aqueous solution at high concentrations, the molar absorption coefficient was determined in DMSO. [g] Excitation wavelength was 360 nm. [h] Fluorescence quantum yields were determined by taking Rhodamine 6G in EtOH (Φ _F=0.94) as a reference. [i] Excitation wavelength was 480 nm. [j] Lifetime was too short to be resolved in the single photon counting (SPC) experiment. [k] Excitation wavelength was 470 nm.