dissociation of the adenine dimer after ionisation, and its action spectrum was found
to be significantly redshifted compared to that reported by Weinkauf and co-workers
(Fig. 10.12).
10.5 Photoelectron Spectroscopy of Nucleotide Anions
If the photon energy becomes greater than the binding energies of the most weakly
bound electrons, electrons can be ejected from nucleotide anions. The photophysics
of anionic mono- and oligonucleotides has been investigated by a number of
1.0
[Duplex A] 5–
[s.s.A] 3–
[Duplex B] 5–
[Quadruplex] 5–
[s.s.B] 3–
[s.s.C] 2–
0.8
0.6
0.4
0.2
0.0
1.0
0.8
0.6
0.4
0.2
0.0
1.0
0.8
0.6
0.4
0.2
0.0
220
Normalized detachment efficiency
Wavelength (nm)
Normalized detachment efficiency Normalized detachment efficiency
230 240 250 260 270 280 290 300
a
b
c
C:
5’-CGCGAATTCGCG-3’
5’-CGCGGGCCCGCG-3’
3’-GCGCCCGGGCGC-5’
3’-GCGCTTAAGCGC-5’
G
T
T
T
T
T
T
T
T
G
G
NH 4
+
NH 4
+
NH 4
+
G
G
G
G
G
G
G
G
G
G
G
G
G
B:
A:
Fig. 10.11 Relative electron photodetachment yields as a function of excitation energy for (a)
[dCGCGAATTCGCG–3H]
3– single strand (s.s.A) and the corresponding duplex
5– (duplex A); (b)
[dCGCGGGCCCGCG–3H]
3– single strand (s.s.B) and duplex, and (c) [dTGGGGT–2H]
2– single
strand (s.s.C), and G-quadruplex
5– (quadruplex). Reprinted with permission from [25]. Copyright
2012 American Chemical Society
10 UV Photophysics of DNA and RNA Nucleotides In Vacuo: Dissociation. . .
199