Table 1.

Overview of spectral properties of probes 1, 2, 3 and 4.

	λ abs [nm]	λ em [nm]	Φ	τ [b] [ns]
HEPES buffer
1	347	416	0.003	0.16
1⋅ZnII	347	407	0.065	0.33
2	358	458	0.140	1.00
2⋅ZnII	357	435	0.760	2.02
3	344	424	0.066	3.36 (420 nm), 6.53 (460 nm)
3⋅ZnII	343	424, 467[a]	0.068	3.51 (420 nm), 6.64 (460 nm)
4	358	477	0.027	3.90
4⋅ZnII	358	472	0.033	3.84
MeCN
1	342	406	0.003	0.22
1⋅ZnII	342	398	0.030	0.60
2	357	437	0.009	0.82
2⋅ZnII	357	437	0.550	3.30
3	333[a], 343	428	0.026	3.63 (400 nm), 6.29 (420 nm)
3⋅ZnII	333, 343[a]	397, 428[a]	0.087	3.36 (400 nm), 5.89 (420 nm)
4	362	433	0.015	1.52 (420 nm), 2.19 (440 nm)
4⋅ZnII	348	420	0.473	3.61 (420 nm), 3.88 (440 nm)

[a] Shoulder. [b] Averaged fluorescence τ from the bi‐exponential decay profile.