Emission enhancement factors (I/I_o) and lifetimes (τ) of complexes 1–4 (10 μM) upon incubation with TCO-OH (100 μM) for 12 h in aerated H₂O/DMSO (99 : 1, v/v) at 298 K.

Complex	I/Ioa	τ b (μs)
1	40.9	0.47
2	28.9	1.02
3	56.2	0.95
4	11.4	0.90

^a I _o and I are the emission intensities of the complexes in the absence and presence of TCO-OH, respectively.

^bThe emission lifetimes of the complexes after incubation with TCO-OH for 12 h. In the absence of TCO-OH, the emission lifetimes of the complexes could not be determined accurately.