pulsed-field ionization electron spectroscopy of al-uracil complex sergiy krasnokutski and...
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PULSED-FIELD IONIZATION PULSED-FIELD IONIZATION ELECTRON SPECTROSCOPY OF ELECTRON SPECTROSCOPY OF
Al-URACIL COMPLEXAl-URACIL COMPLEX
Sergiy Krasnokutski and Dong-Sheng Yang
University of Kentucky, Lexington, KY 40506, USA
$ National Science Foundation $$ National Science Foundation $
Motivation: metal interaction with structural Motivation: metal interaction with structural components of nucleic acids.components of nucleic acids.
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23
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5
6
BackgroundBackground
1. a) M.T. Rodgers et al., J. Am. Chem. Soc. 2000, 122, 8548-8558 b) B.A. Cerda et al., J. Am. Chem. Soc. 1996, 118, 11884-11892
2. a) D.B. Pedersen et al., J. Am. Chem. Soc. 2002, 124, 6686-6692 b) D.B. Pedersen et al., J. Phys. Chem. A 2003, 107, 6464-64693. S. Hoyau et al., J. Am. Chem. Soc. 1999, 121, 8864-8875
1. Threshold collision-induced dissociation a) Li+, Na+, K+ with uracil, thymine, and adenine
b) Li+, Na+, and K+ binding to the DNA and RNA nucleobases. 2. Photoionization efficiency spectra
a
b
Al-Cytosine
Al-GuanineNa+(Uracil ) + Xe
Tautomers and Energies (kcal/mol) of UracilTautomers and Energies (kcal/mol) of Uracil
N1O2, E=19.9 (19.8)
1, E=0 N3O4, E=12.4 (12.1)
N1O4, E=21.9 (21.8) N3O2, E=19.8 (19.8)
N1N3, E=15.0 (14.4)N1N3`, E=13.8 (14.2)
N1O2`, E=11.6 (11.4)
B3LYP/6-311+G(d,p) (B3P86/6-311+G(d,p))B3LYP/6-311+G(d,p) (B3P86/6-311+G(d,p))
N1O2N1, E=34.7 (34.2)
N3O4N3, E=11.0 (8.5) N1O4N1, E=13.0 (10.8)
N3O2N3, E=14.4 (13.2)
1O4, E=0
1O2, E=18.0 (18.2)1CC, E=23.4 (20.3)
N1N3N1, E=26.1 (26.2) N1N3N3, E=29.3 (28.9)
Tautomers and Energies (kcal/mol) of Al-UracilTautomers and Energies (kcal/mol) of Al-Uracil
B3LYP/6-311+G(d,p) (B3P86/6-311+G(d,p))B3LYP/6-311+G(d,p) (B3P86/6-311+G(d,p))
1O2, E=6.5 (6.3)
N1O2N1, E=30.0 (33.9)
N3O4O2, E=6.8 (6.5) N1O4O2, E=10.0 (9.7)
N3O2O4, E=4.5 (4.3)1O4, E=0
N1N3N3, E=27.6 (27.7)
N1N3N1, E=18.1 (18.1)
Tautomers and Energies (kcal/mol) of AlTautomers and Energies (kcal/mol) of Al++-Uracil-Uracil
B3LYP/6-311+G(d,p) (B3P86/6-311+G(d,p))B3LYP/6-311+G(d,p) (B3P86/6-311+G(d,p))
AlAl++ Stabilization of High Energy Tautomers Stabilization of High Energy Tautomers
E (kcal/mol)
0
1
N3O2
19.8
UracilAl+ Uracil
N1O2`
11.6
11.6
1O4
N1O2N1
N3O2O4
4.5
ZEKE Experimental SetupZEKE Experimental Setup
HV
M CP
TP 400L/s
TP 400L/sDP 2300L/s
Extraction Cans
Tim e of Flight Tube
M etal
G ateValve
Sk immer
H e 30 p si
P u lsed Va lve
53 2 n m
M eta l-ligan d R od
Mass and PIE Spectra of Al-Uracil
Experimental and Experimental and SSimulatimulated Spectraed Spectra of of AlAlUUracilracil Tautomers Tautomers
Wavenumber / cm-1
43000 43200 43400 43600 43800 44000 44200 44400
Rel
ativ
e in
tens
ity
Experiment
18 kcal/mol
Lowest energy conformer
kcal/mol
E=35 kcal/mol
B3LYP/6-311+G(d,p)B3LYP/6-311+G(d,p)
IE=43261 cm-1
IE=43064 (7) cm-1
IE=39087 cm-1
IE=39908 cm-1
IE=41152 cm-1
Experimental and Experimental and Simulated SpectraSimulated Spectra
43000 43200 43400 43600 43800 44000 44200 44400
Rel
ativ
e in
tens
ity
B3LYP
B3P86
MP2
Wavenumber / cm-1
51
51 51
5151
515151
51
303
experimentexperiment B3LYPB3LYP B3P86B3P86
5151 3838 6161
5151 2020 6060
303303 300300 300300
Vibrational intervals (cm-1)
43000 43200 43400 43600 43800 44000 44200
Re
lative
in
ten
siti
es
Wavenumber / cm-1
Experimental and Simulated SpectraExperimental and Simulated Spectra
Li-Thymine and Li-Uracil ComplexesLi-Thymine and Li-Uracil Complexes
IE = 33386(7)
IE = 33910(7)
Metal binding to the O4 atom of uracil Metal binding to the O4 atom of uracil and thymine.and thymine.
Density functional theory gives good Density functional theory gives good agreement with the experiment.agreement with the experiment.
AlAl++ ion stabilizes unusual tautomeric ion stabilizes unusual tautomeric forms.forms.
ConclusionsConclusions