Table 2.

Fluorescence quantum yields, lifetimes, and dynamics of electron transfer

Hairpin*	Φf†	τs‡, ns	ket§, s−1
A-PA	0.41	24.8	<106
1I-PA	0.27	19.8	1.0  × 107
2I-PA	0.33	24.4	≈1  × 106
1G-PA	≈0.001	0.07	1.4  × 1010
2G-PA	0.01	0.47	2.1  × 109
3G-PA	0.22	14.9	2.7  × 107¶
4G-PA	0.37	25.9	<106
2Z-PA	≈0.002	0.10	1.0  × 1010
3Z-PA	0.02	2.6	3.4  × 108
4Z-PA	0.28	22.5	4  × 106

Data from this study, except as noted, are for deoxygenated solutions of 5 × 10⁻⁶ M hairpin in aqueous buffer containing 0.1 M NaCl. 

^*See Fig. 1 for structures. 

^† Fluorescence quantum yields determined by comparison to quinine sulfate. Limits of error for multiple determination ±10%. 

^‡ Fluorescence decay times. Nanosecond decays determined as described in ref. 33 are all single exponential. Subnanosecond decays determined as described in ref. 34 can be fit to either single or double exponential functions with long-lived decay components of 2.9 ns for 1G-PA and 3.9 ns for 2Z-PA. 

^§ k_et = τ − τ, where τ_o is the decay time of the hairpin A-PA. 

^¶ Data from ref. 33.