Photophysical properties of the studied Cy7 fluorophores.

	λ abs a/nm	λ em a/nm	ε a b	d c/%	Φ F ×102ad	χ e/%	εΦ F
1H	992	1029	280 800	—	1.33 ± 0.08	—	3730
1D	990	1022	268 700	14	1.56 ± 0.09	17 ± 0.9	4190
1DD	982	1015	296 300	47	2.39 + 0.02	80 ± 0.8	7080
2H	987	1014	236 900	—	0.33 ± 0.026	—	780
2D	986	1011	219 900	21	0.36 ± 0.025	9.9 ± 0.9	790
3H	832	860	224 300	—	0.06 ± 0.004	—	130
3D	832	860	237 900	26	0.05 ± 0.004	−17 ± 1.0	120
4H	784f	830	226 000f	—	11.5 ± 0.6	—	26 000
4D	782f	834	169 700f	12	13.7 ± 0.6	19 ± 0.7	23 100

^aDetermined in DCM with 0.4% of DMSO.

^bThe molar absorption coefficient, ε_max/mol⁻¹ dm³ cm⁻¹.

^cOverall degree of the deuteration.

^dQuantum yield of fluorescence relative to the reference. Average and standard deviations of the mean are given.

^eEnhancement of the quantum yield of fluorescence by deuteration defined as χ = 100 × (Φ_D/Φ_H −1).

^fDetermined in MeOH with 0.4% DMSO due to its aggregation in DCM.