Table 2.

pH sensing properties of the perylene dyes in solution and embedded in hydrogel D4.^[a]

THF/EtOH/buffer (3:2:2, v/v/v)		Hydrogel D4
Dye	pK a abs	λ abs (acidic/monoanionic) [nm]	pK a′ abs	λ em (acidic/monoanionic) [nm]	pK a′ em
2 a	10.63	596/689	10.88	608/728	10.14
2 b	10.15	596/684	10.73	608/720	9.84
2 c	10.78	586/664	11.45	595/708	10.56
3 a	10.68	650/731	11.36	662/768	10.15

[a] Ionic strength (NaCl): 0.15 m, T=25 °C.