. Author manuscript; available in PMC: 2012 Jul 1.

Published in final edited form as: J Org Chem. 2011 May 27;76(13):5219–5228. doi: 10.1021/jo2005654

Table 1.

Photophysical properties of 1 – 4 in 1:1 ethanol:CH₂Cl₂.

cmpd	base^a	absorption^b		fluorescence^c		φ_acceptor excited at acceptor^d	φ_acceptor excited at donor^e,^j	ETE (%)^f	φ_donor^g
cmpd	base^a	λ_{max donor} (nm)/ε × 10⁻⁴	λ_{max acceptor} (nm)/ε × 10⁻⁴	λ_{max donor} (nm)	λ_{max acceptor} (nm)	φ_acceptor excited at acceptor^d	φ_acceptor excited at donor^e,^j	ETE (%)^f	φ_donor^g
1	−	505/5.6	575/3.5	521	600	0.30ⁱ	0.15	51	0.05
1	+	505/11	578/3.0	529	-	0.01ⁱ	-	< 5	0.09
2	−	506/3.7	560/1.9	528	579	0.24^j	0.09	38	0.07
2	+	505/13	561/2.8	529	-	0.01^j	-	< 5	0.08
3	−	502/14	566/6.6	513	606	0.62ⁱ	0.58	93	-^h
3	+	502/14	566/6.6	516	604	0.66ⁱ	0.60	92	-^h
4	−	502/11	561/4.7	521	588	0.84^j	0.79	94	-^h
4	+	502/11	560/5.2	515	588	0.93^j	0.85	91	-^h

with ⁿBu₄NOH at a concentration of 8 × 10⁻⁵ M.

At 1 × 10⁻⁵ M.

At 1 × 10⁻⁶ M.

Quantum yield of acceptor when excited at the acceptor.

Quantum yield of acceptor while excited at the donor.

Energy transfer efficiency calculated with the quantum yield of the acceptor with excitation at donor divided by that with excitation at the acceptor.

Fluorescein (φ = 0.92 in 0.1 M NaOH)³⁴ was used as a standard.

Donors in these cassettes show no significant fluorescence emission.

ⁱ

Rhodamine 101 (φ = 1.00 in EtOH)³⁵ was used as a standard.

Rhodamine B (φ = 0.97 in EtOH)³⁴ was used as a standard.