Table 2.

Optical properties of the tC^O monomer and tC^O-containing RNA single strands.

Sequence namea	λAbs,max [nm]b	λEm,max [nm]b	ΦF b,c	τ1(α1) [ns]b,d	τ2(α2) [ns]b,d	<τ>[ns]e	kr [107 s−1]f	knr [108 s−1]g
tC O monomer	359	457	0.30	3.4 (1.00)	—	3.4	8.8	2.1
GG	367	455	0.31	5.7 (0.71)	2.4 (0.29)	4.7	6.6	1.5
UG	364	456	0.21	4.1 (0.63)	1.6 (0.37)	3.2	6.6	2.5
GU	364	458	0.19	3.9 (0.57)	1.4 (0.43)	2.8	6.8	2.9
AA	368	458	0.34	5.8 (0.89)	2.0 (0.11)	5.4	6.3	1.2
AU	363	457	0.22	4.3 (0.64)	1.4 (0.36)	3.3	6.7	2.4
CC	368	453	0.33	5.6 (0.80)	2.2 (0.20)	4.9	6.7	1.4
GUUU	364	457	0.17	3.9 (0.50)	1.3 (0.50)	2.6	6.5	3.2
GAUU	364	457	0.22	4.4 (0.62)	1.5 (0.38)	3.3	6.7	2.4
UUUG	362	458	0.21	4.1 (0.63)	1.4 (0.37)	3.1	6.8	2.5

^aSequences are named after the bases flanking tC^O (see Fig. 1b). Full sequences can be found as Supplementary Table S1. ^bMeasurements were performed in PBS buffer (100 mM Na⁺, pH 7.5). ^cFluorescence quantum yields are measured relative to the quantum yield of the potassium salt of the tC^O-monomer in water (Φ_F = 0.30)³¹. ^dThe amplitudes are indicated in parenthesis. ^eMean fluorescence lifetime <τ> = ∑α_iτ_i/∑α_i. ^fRadiative rate constant, k_r = Φ_F/<τ>. ^gNon-radiative rate constant, k_nr = k_r/Φ_F − k_r.