Stern–Volmer constants (K_SV) for complexes with dyads 3a–d.

Mn+	3a	3b	3c	3d
Hg2+, λex: 315 nm	3.79 × 104 M−1 (R2 = 0.99)	3.30 × 104 M−1 (R2 = 0.99)	3.13 × 104 M−1 (R2 = 0.99)	5.51 × 104 M−1 (R2 = 0.95)
Cu2+, λex: 315 nm	3.30 × 103 M−1 (R2 = 0.95)	3.40 × 103 M−1 (R2 = 0.94)	3.50 × 103 M−1 (R2 = 0.97)	1.55 × 104 M−1 (R2 = 0.98)
K SV(Hg2+)/KSV(Cu2+)	11.5	9.7	8.9	3.6