1. Sodium-Glucose Interactions in the Gas Phase STEVE KREGEL ISMS 2015 6-23-15

2. Glucose-Ion Interactions α/β ratio of 36:64 in solution Metal cations shown to affect solution α/β ratio Ca 2+ strongly favors α anomer, Na + has weaker effect 2 Franks, F., Hall, J. R., Irish, D. E., Norris, K.: Carbohydr. Res. 157, 53-64 (1986)

3. Glucose-Ion Interactions Many potential Na + binding sites, resulting in unique hydrogen bonding Problem: Water background obscures local H-bonding environment Solution: Gas-phase spectroscopy 3 Heaton, A. L., Armentrout, P. B.: J. Phys. Chem. A 112, 10156- 10167 (2008)

4. Cryogenic Ion Vibrational Spectroscopy 4 IR Excitation Vibrational Redistribution D 2 Ejection

5. Equilibrium (Na-Glucose) + 5 28002900300031003200330034003500360037003800 A 35003520354035603580360036203640366036803700 B C D E F G H I J K L M N O H-bonding strength Free OH CH Stretch

6. Spectral Assignment 6 α 2 +8.8 kJ/mol β 0 +4.4 kJ/mol α 3 +9.5 kJ/mol H C All calculations done at the cam-B3LYP/6- 311+G(d,p) level

7. β 1 +6.0 kJ/mol Spectral Convolution 7 α 0 +0.0 kJ/mol β 2 +12.3 kJ/mol β 4 +14.3 kJ/mol

8. Solution Phase Sampling 8 Equilibrium spectrum shows αβ ratio of 37:63 ◦Solution ratio 36:64 Non-equilibrium spectrum shows significant differences ◦α/β ratio of 56:44 ◦Presence of α 1 conformer Non-unique free OH α2α2 α2α2 α1α1 α0α0 β2β2 β0β0

9. Binding Energetics ExperimentGas-Phase DFT (kJ/mol) Conformer Population (%)ΔE (0K)Population (%) α0α0 280.033 α1α1 08.62 α2α2 98.81 α3α3 09.50 Total α37 β0β0 174.428 β1β1 196.025 β2β2 1812.35 β3β3 013.71 β4β4 914.34 Total β63 9 Experimental gas phase binding energy of 180 kJ/mol Solution binding energy calculated to be 21.8 kJ/mol Average gas phase conformer conversion barrier of ~20 kJ/mol Mayes, H. B., Tian, J., Nolte, M. W., Shanks, B. H., Beckham, G. T., Gnanakaran, S., Broadbelt, L. J.: J. Phys. Chem. B 118, 1990-2000 (2014)

10. Future Work Double resonance Analyze Li-(Glucose) + spectrum Conformer search and spectral acquisition for Ca-(Glucose) 2+ 10 Li-(Glucose) +

11. Acknowledgments 11 Brett Marsh Jia Zhou Etienne Garand The Garand Group