Table 1.

Optical properties measured in dichloromethane (CH₂Cl₂) and in pH 7.4 PBS.

Entry	${\lambda }_{\mathrm{abs}}$ (nm) (CH2Cl2 / PBS)	${\lambda }_{\mathrm{em}}$ (nm) (CH2Cl2 / PBS)	$\mathrm{\epsilon }$ (M−1 cm−1) (CH2Cl2 / PBS)	${\mathrm{\Phi }}_{\mathrm{F}}$ (CH2Cl2 / PBS)	$\mathrm{\epsilon }\times {\mathrm{\Phi }}_{\mathrm{F}}$ (PBS)	${\tau }_{\mathrm{i}}$ (ns) (CH2Cl2)
Ros*	–/549	–/570	–/72 000	–/0.31	22 320	-
KR-1	855/862	911/1058	28 400/16 500	0.013/0.00013	2.15	0.346
KR-2	848†/–	907†/–	4700/–	0.00029/–	1.36	-
KR-3	855/870	919/1065	15 600/9500	0.0031/0.00017	1.62	-
KR-4	–/874‡	–/1058‡	–/1600‡	-	-	-

^*Ref. (62)

^†CH₂Cl₂ w/ 5% TFA

^‡acetate buffer (0.05 M) pH 3.6. The quantum yield (Q.Y.) of KR-1 was measured against IR-140 in DMSO as a reference (assuming a Q.Y. of 20%). KR-1 was used as a standard for subsequent Q.Y. measurements. See Section S5 for additional data and discussion.