Hydrogen-Atom Tunneling in Metaphosphorous Acid

Weiyu Qian; Xianxu Chu; Chao Song; Zhuang Wu; Mengqi Jiao; Hanwen Liu; Bin Zou; Guntram Rauhut; David P Tew; Lina Wang; Xiaoqing Zeng

doi:10.1002/chem.202000844

Hydrogen-Atom Tunneling in Metaphosphorous Acid

Chemistry. 2020 Jul 2;26(37):8205-8209. doi: 10.1002/chem.202000844. Epub 2020 Jun 12.

Authors

Weiyu Qian¹, Xianxu Chu¹, Chao Song¹, Zhuang Wu¹, Mengqi Jiao¹, Hanwen Liu¹, Bin Zou¹, Guntram Rauhut², David P Tew³, Lina Wang⁴, Xiaoqing Zeng^{1

4}

Affiliations

¹ College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123, Suzhou, China.
² Institute for Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, Stuttgart, 70569, Germany.
³ Max-Planck Institute for Solid State Research, Heisenbergstraße 1, Stuttgart, 70569, Germany.
⁴ Department of Chemistry, Fudan University, Shanghai, 200433, China.

PMID: 32302021
DOI: 10.1002/chem.202000844

Abstract

Metaphosphorous acid (HOPO), a key intermediate in phosphorus chemistry, has been generated in syn- and anti-conformations in the gas phase by high-vacuum flash pyrolysis (HVFP) of a molecular precursor ethoxyphosphinidene oxide (EtOPO→C₂ H₄ +HOPO) at ca. 1000 K and subsequently trapped in an N₂ -matrix at 2.8 K. Unlike the two conformers of the nitrogen analogue HONO, the anti-conformer of HOPO undergoes spontaneous rotamerization at 2.8 K via hydrogen-atom tunneling (HAT) with noticeable kinetic isotope effects for H/D (>10⁴ for DOPO) and ¹⁶ O/¹⁸ O (1.19 for H¹⁸ OPO and 1.06 for HOP¹⁸ O) in N₂ -matrices.

Keywords: IR spectroscopy; conformation; kinetic isotope effects; phosphorus acids; quantum mechanical tunneling.

Abstract

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