TABLE 1.

Photophysical characteristics of the imidazolone derivatives in dioxane

Derivative	R1	R2	R3	Extinction coefficient (M−1·cm−1)	λmaxabs (nm)	λmaxemis (nm)	φ*
I-1	OH	Me	Me	25500	370	440	0.0001
I-2†	OH	Me	(CH2)3Me	26600	372	436	0.0001
I-3	OH	Ph	H	32600	399	467	0.0002
I-4†	OH	3,4-diMeOPh	Me	28700	398	476	0.0002
I-5	H	Ph	H	13100	384	444	0.0012
I-6	H	Ph	OH	19700	385	443	0.0002
I-7	H	Ph	Ph	19500	380	453	0.001
I-8†	H	4-MeOPh	H	26100	387	452	0.032
I-9†	H	3,4-diMeOPh	H	23000	390	457	0.034
I-10†	H	3,4-diMeOPh	Me	25900	386	470	0.045
I-11	MeO	Ph	H	15400	398	464	0.0002
I-12†	MeO	Ph	Me	16800	394	471	0.0002
I-13†	MeO	Ph	CH2COOEt	25900	389	465	0.0002
I-14†	MeO	Ph	CH2Ph	20600	393	468	0.0002
I-15†	MeO	4-NO2Ph	H	22200	428	573	0.060
I-16†	OCH2COOEt	Ph	H	19100	397	461	0.0003
I-17	H, 2-MeO	Ph	H	26300	400	465	0.0022
I-18†	N(Me)2	Me	H	39900	415	483	0.0009
I-19	N(Me)2	Ph	H	38800	454	520	0.0020
I-20†	N(Me)2	4-MeOPh	H	37000	450	507	0.0023
I-21	N(Me)2	3,4-diMeOPh	H	50300	455	515	0.0025
I-22†	CF3	Ph	H	22000	383	451	0.135
I-23†	CN	Ph	H	24800	393	464	0.158
I-24†	COOMe	Ph	H	28800	394	461	0.159
I-25†	CN	4-MeOPh	H	29200	401	482	0.159
I-26†	CN	3,4-diMeOPh	H	26500	405	482	0.189
I-27†	COOMe	3,4-diMeOPh	H	32200	403	478	0.295
I-28†	CN	4-NO2Ph	H	20700	406	508	0.220
I-29†	COOMe	4-NO2Ph	H	25300	405	510	0.258

^*Fluorescence quantum yields φ determined at 293 K. SEM of 0.001 for φ between 0.010 and 0.099 and of 0.005 for φ between 0.100 and 0.300.

^†New products.