Table 4. Photophysical Properties of Compound 4k.

entry	solvent	absorptionaλmax,abs (nm)	emissionaλmax,emi (nm)	molar extinction coefficient × 104 (ε) π–π*	Stoke’s shift Δν̅ (cm–1)b	quantum yield (Φf)c
1	CH3CN	231	418	7.6462	19 366	0.1522
2	MeOH	233	463	10.3089	21 320	0.1580
3	THF	249, 357	408	3.41119	15 650	0.2754
4	dioxane	272, 356	407	1.54363	12 194	0.7916
5	toluene	288, 353	408	1.12686	10 212	0.8019

^aRecorded at 298 K.

^bStoke’s shift = λ_max,abs – λ_max,emi [cm^–1].

^cDetermined with anthracene as a standard Φ_f = 0.27 at an excitation wavelength of 246 nm.