1. Proton Sponges: A Rigid Organic Scaffold to Reveal the Quantum Structure of the Intramolecular Proton Bond Andrew F. DeBlase, Michael T. Scerba, Thomas Lectka, and Mark A. Johnson June 22, 2012 1 8

2. Background Tom Lectka (organic): Isolate exotic charged H-bonds Scerba et. al. J. Org. Chem. 2011 - e.g. Charged H-bond to F Our work: Shared proton often a distinct feature in cold ions Roscioli et. al. Science 2007 Ar-predissociation of cryogenic ions 1000 15002000250030003500 Photon Energy (cm -1 ) Stoyanov and Reed J. Phys. Chem. A 2006 Room temperature FTIR

3. Background Tom Lectka (organic): Isolate exotic charged H-bonds Scerba et. al. J. Org. Chem. 2011 - e.g. Charged H-bond to F Our work: Shared proton often a distinct feature in cold ions “I think this is the beginning of a beautiful friendship.”

4. Background Tom Lectka (organic): Isolate exotic charged H-bonds Scerba et. al. J. Org. Chem. 2011 - e.g. Charged H-bond to F Our work: Shared proton often a distinct feature in cold ions “I think this is the beginning of a beautiful friendship.” Can you make an H-bond to the ether oxygen of an ester?

5. Why Is This Unusual? The carbonyl O has a much higher proton affinity!

6. Why Is This Unusual? The carbonyl O has a much higher proton affinity! Very Fast Bohme Int. J. Mass Spectrom. 2000 Blue shift? ν CO

7. Experimental Setup Ion optics Electrospray Needle RF Only Quadrupoles Octopoles Pressure (Torr) 3D Quadrupole Ion Trap with Temperature Control to 8 K TOF to IR Spectrometer New Cryogenic Ion Source 3×10 -7 1×10 -5 1.5×10 -2 1.5760 Heated Capillary 90 ° Ion Bender Wiley- McLaren Extraction Region

8. + D 2 13 C 290292294296298300 m/z The Experiment *

9. + D 2 13 C 290292294296298300 m/z The Experiment hνhν OPO/OPA LaserVision Mid Infrared Laser Apply mass gate to ion of interest

10. + D 2 13 C Time of Flight Monitor photofragment as a function of laser energy The Experiment

11. Photon Energy (cm -1 ) ν NH 100012001400160018002800300032003400 Predissociation Yield, Calculated Intensity Blue Shifted Carbonyl: Evidence for a Strong Intramolecular H-Bond Scerba et. al. J. Phys. Chem. A. 2012. ν CO 3378 1580 1720 ν OH = 3313 ν CO = 1500-1700 1792 B3LYP/6-311++G** (unscaled) B3LYP/6-311++G** (CH scaled by 0.961, NH scaled by 0.945) Douberly, et. al. PCCP 2008 Course, et. al. JOC 1981 Wow!!!

12. Photon Energy (cm -1 ) ν NH 100012001400160018002800300032003400 Predissociation Yield, Calculated Intensity Blue Shifted Carbonyl: Evidence for a Strong Intramolecular H-Bond Scerba et. al. J. Phys. Chem. A. 2012. ν CO 1792 B3LYP/6-311++G** (unscaled) B3LYP/6-311++G** (CH scaled by 0.961, NH scaled by 0.945) + + + Is the complexity from the reaction coordinate?

13. Predissociation Yield, Calculated Intensity Photon Energy (cm -1 ) 280030003200340036003800 Calculated: B3LYP/6-311++G** Scaled by 0.966 Tuning the Shared Proton Frequency 2750-3200 · D 2 3614 3637 · D 2

14. Predissociation Yield, Calculated Intensity Photon Energy (cm -1 ) 15002000250030003500 Calculated: MP2/6-311++G** Scaled: OH = 0.945, CH/NH = 0.957, below 2000 cm -1 = 0.972 Alcohol Isotopologues 2750-3200 3614 3637 Case 1: ND OH Case 2: NH OD

15. Photon Energy (cm -1 ) Predissociation Yield, Calculated Intensity 15002000250030003500 Calculated: MP2/6-311++G** Scaled: OH = 0.945, CH/NH = 0.957, below 2000 cm -1 = 0.972 Alcohol Isotopologues 2750-3200 2264 2268 3614 2672 3637 2687

16. Photon Energy (cm -1 ) Predissociation Yield, Calculated Intensity ~ X 4 Laser Power 15002000250030003500 Alcohol Isotopologues

17. 1200 1600 2000240028003200 Photon Energy (cm -1 ) Predissociation Yield, Calculated Intensity Ester Isotopologues Woof, woof!! 2267 2750-2960 2960-3200 1793 1795

18. Conclusions/Future Work Revealed signature carbonyl of O ether H-bond interaction NH stretching region complicated through couplings to other oscillators and possibly dark states - Can we tune through these by making Δ PA even smaller? Can the shared proton launch a chemical reaction?

19. Acknowledgements Labmates: Past and Current Mark: New science, new hobbies! Tom Lectka’s group at JHU for making the molecules! Ken Jordan for help with calculations Anne McCoy for useful conversations about anharmonicity Funding: National Science Foundation, Air Force