pulsed-field ionization electron spectroscopy of al-uracil complex sergiy krasnokutski and...

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.

1

23

4

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