TABLE 1.

Optical data (absorption and fluorescence maxima, Stokes shift, and absolute fluorescence quantum yield (Φ _F)) of D1 and D2 systems in solvents with a decreasing dielectric constant (ε) under anaerobic conditions. Fluorescence and Φ _F measurements were recorded upon excitation at 365 nm.

Sample	Solvent, dielectric constant (ε)	Abs. max., λ abs (nm)	Fluor. max., λ em (nm)	Stokes shift, Δλ (nm)	Φ F (%)	Nature of the solvent
D1	Dimethylsulfoxide (DMSO, ε = 46.7)	265 and 376	410, 436, and 609	233	16	Polar aprotic
	Acetonitrile (ACN, ε = 37.5)	260 and 349	418 and 593	244	19
	Dimethylformamide (DMF, ε = 36.7)	265 and 373	410, 438, and 588	215	29
	Methanol (MeOH, ε = 32.7)	260 and 361	410, 445, and 608	247	2	Polar protic
	Ethanol (EtOH, ε = 24.5)	261 and 364	410 and 595	231	7
	Dichloromethane (DCM, ε = 8.9)	261 and 369	525	156	82	Medium polar
	Ethyl acetate (AcOEt, ε = 6.0)	261 and 362	514	152	54
	Chloroform (CHCl3, ε = 4.8)	262 and 365	497	132	41
	Toluene (Tol, ε = 2.4)	286 and 365	452	87	87	Non-polar
	Benzene (Bz, ε = 2.3)	278 and 365	455	90	96
	Hexane (Hx, ε = 1.9)	259 and 354	403, 425, and 454	49	87
D2	Dimethylsulfoxide (DMSO, ε = 46.7)	287, 307, and 374	411 and 574	200	79	Polar aprotic
	Acetonitrile (ACN, ε = 37.5)	265, 303, and 365	411 and 574	209	78
	Dimethylformamide (DMF, ε = 36.7)	279, 306, and 372	411 and 559	187	87
	Methanol (MeOH, ε = 32.7)	265, 304, and 365	411, 447, and 600	235	3	Polar protic
	Ethanol (EtOH, ε = 24.5)	268, 305, and 367	411 and 571	204	31
	Dichloromethane (DCM, ε = 8.9)	269, 307, and 371	520	149	91	Medium polar
	Ethyl acetate (AcOEt, ε = 6.0)	257, 304, and 366	493	127	82
	Chloroform (CHCl3, ε = 4.8)	266, 308, and 372	493	121	84
	Toluene (Tol, ε = 2.4)	286, 306, and 373	444	71	96	Non-polar
	Benzene (Bz, ε = 2.3)	287, 307, and 371	445	74	69
	Hexane (Hx, ε = 1.9)	267, 303, and 366	411, 434, and 465	45	75