1. PULSED-FIELD IONIZATION ELECTRON SPECTROSCOPY OF Al-URACIL COMPLEX Sergiy Krasnokutski and Dong-Sheng Yang University of Kentucky, Lexington, KY 40506, USA $ National Science Foundation $

2. Motivation: metal interaction with structural components of nucleic acids. 1 2 3 4 5 6

3. Background 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, 6464-6469 3. 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-Guanine Na + (Uracil ) + Xe

4. Tautomers 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))

5. 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-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))

6. 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 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))

7. Al + Stabilization of High Energy Tautomers  E (kcal/mol) 0 1 N3O2 19.8 UracilAl + Uracil N1O2` 11.6 1O4 N1O2N1 N3O2O4 4.5

8. ZEKE Experimental Setup

9. Mass and PIE Spectra of Al-Uracil

10. Experimental and Simulated Spectra of Al  Uracil Tautomers 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

11. Experimental and Simulated Spectra 303experimentB3LYPB3P86513861 512060 303300300 Vibrational intervals (cm -1 )

12. Experimental and Simulated Spectra

13. Li-Thymine and Li-Uracil Complexes IE = 33386(7) IE = 33910(7)

14.  Metal binding to the O4 atom of uracil and thymine.  Density functional theory gives good agreement with the experiment.  Al + ion stabilizes unusual tautomeric forms. Conclusions