Wei Li, Mingfei Zhou Fudan University , Shanghai, China Infrared Spectroscopic and Theoretical Study of the HCnO+ (n = 5-12) Cations Wei Li, Mingfei Zhou Fudan University , Shanghai, China Talk FA09, 72th ISMS, June 2017

Content 1. Background 2. Experimental and Computational Methods 3. Results and discussion 4. Conclusions

Background Carbon chains and derivatives Potential interstellar molecules Highly active species Reactive intermediates H. Herrmann, et al. J. Atmos.Chem. 2000, 36, 231 D. L. Baulch, et al. J. Phys. Chem. 2005, 34, 757 P. Ehrenfreund, et al. Annu. Rev. Astron. Astrophys. 2000, 38, 427

Background Spectroscopy Rotational spectra HC5O and HC7O radicals HCnO (n = 1-9) Mass spectrometry HCnO+ ions Electronic spectra HC7O+ cation S. Mohamed, et al. J. Chem. Phys. 2005, 123, 234301 A.C.Simmonett, et al. J.Phys.Chem.A.2009,113,11643 S. Peppe, et al. J. Phys. Chem. A. 2000, 104, 5817 A. Chakraborty, et al. Mol. Phys. 2016, 114, 2794

Experimental Method AB+ ~ l IR photodissociation spectrum G. J. Wang, et al. J. Phys. Chem.A. 2012, 116, 2484 G. J. Wang, et al. Sci. China: Chem. 2014, 57, 172

Computational Method Geometries and frequencies B3LYP-D3 Aug-cc-pVTZ Scale factor 0.968 Bonding analyses Natural orbital analysis(NBO) Adaptive natural density partitioning(AdNDP) A. E. Reed, et al. J. Chem. Phys. 1985, 83, 735 D. Y. Zubarev, et al. Phys. Chem. Chem. Phys. 2008, 10, 5207

Mass spectrum C + CO/H2/He HCnO+ (n = 5-12) [HCnO·CO]+ (n = 5-12)

IR photodissociation spectra of [HCnO·CO]+ C-C C-O C-H n = 5 n = 7 n = 9 n = 11 n = 6 n = 8 n = 10 n = 12

The stability of linear carbon chain cations HC5O+ (e) 1A1 ; C2v; ΔE = 58.7 kcal/mol (d) 3Σ-; C∞V; ΔE = 56.7 kcal/mol (c) 1A ; Cs; ΔE = 55.9 kcal/mol (b) 1A ; Cs; ΔE = 54.7 kcal/mol (a) 1Σ+; C∞V; ΔE = 0.0 kcal/mol

Negligible effect of CO-tagging (b) 1Σ+ [HC5O]+ (C∞V) (a) 1A [HC5O·CO]+ (Cs)

Geometries and NBO analyses [HCnO]+ (n = 5,7,9,11); 1Σ+; C∞V Polyyne-like structures n = 5 n = 7 n = 9 n = 11 *Bond lengths in angstroms and Wiberg bond orders (values in brackets)

Geometries and NBO analyses [HCnO]+ (n = 6,8,10,12); 3Σ-;C∞V allene-like structures n = 8 n = 10 n = 12 *Bond lengths in angstroms and Wiberg bond orders (values in brackets)

AdNDP 1×1c-2e LPs ON=|1.98e| 2×3c-2e π ON=|2.00e| 2×4c-2e π ON=|2.00e| 6×2c-2e σ ON=|1.99e-2.00e| 2×6c-2e π ON=|2.00e| The adaptive natural density partitioning analyses (AdNDP) of HC5O+

Conclusions The HCnO+ (n = 5-12) core cations are characterized to be linear carbon chain derivatives terminated by hydrogen and oxygen. The HCnO+ cations with odd n have closed-shell singlet ground states with polyyne-like structures, while those with even n have triplet ground states with allene-like structures. The AdNDP bonding analysis indicates that along with the localized two-center-two-electron  bonds, there are pairs of multiple-center-two-electron delocalized π bonds on the CnO chains.

Acknowledgment Advisor: Prof. Mingfei Zhou Zhou Group: Dr. Guanjun Wang Jiaye Jin

Thank you very much for your attention!

Q&A n=5 n=7 Structure Experimental (black) and simulated (c)1Σ+ [HC5O]+ (C∞V) n=5 (b) 1A [HC5O·CO]+ (Cs) (c)1Σ+ [HC7O]+ (C∞V) n=7 Experimental (black) and simulated (red) vibrational spectra (b) 1A [HC7O·CO]+ (Cs) Structure

Q&A n=9 n=11 Structure Experimental (black) and simulated (c)1Σ+ [HC9O]+ (C∞V) n=9 (b) 1A [HC9O·CO]+ (Cs) n=11 (c)1Σ+ [HC11O]+ (C∞V) Experimental (black) and simulated (red) vibrational spectra (b) 1A [HC11O·CO]+ (Cs) Structure

Q&A n=6 n=8 Structure Experimental (black) and simulated (d)3Σ- [HC6O]+ (C∞V) n=6 (c)3A [HC6O·CO]+ (Cs) (b)3Σ- [HC6O·CO]+ (C∞V) n=8 (c)3Σ- [HC8O]+ (C∞V) Experimental (black) and simulated (red) vibrational spectra (b)3A [HC8O·CO]+ (Cs) Structure

Q&A n=10 n=12 Structure Experimental (black) and simulated (c)3Σ- [HC10O]+ (C∞V) n=10 (b)3A [HC10O·CO]+ (Cs) (c)3Σ- [HC12O]+ (C∞V) n=12 (b)3A [HC12O·CO]+ (Cs) Experimental (black) and simulated (red) vibrational spectra Structure

Q&A The adaptive natural density partitioning analyses (AdNDP) of HC6O+ The adaptive natural density partitioning analyses (AdNDP) of HC8O+ The adaptive natural density partitioning analyses (AdNDP) of HC10O+ The adaptive natural density partitioning analyses (AdNDP) of HC12O+

Q&A The adaptive natural density partitioning analyses (AdNDP) of HC7O+ The adaptive natural density partitioning analyses (AdNDP) of HC9O+ The adaptive natural density partitioning analyses (AdNDP) of HC11O+