Hydrogen-Atom Tunneling in Metaphosphorous Acid.

Authors :: Qian W
Chu X
Song C
Wu Z
Jiao M
Liu H
Zou B
Rauhut G
Tew DP
Wang L
Zeng X
Source :: Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2020 Jul 02; Vol. 26 (37), pp. 8205-8209. Date of Electronic Publication: 2020 Jun 12.
Publication Year :: 2020
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→C <subscript>2</subscript> H <subscript>4</subscript> +HOPO) at ca. 1000 K and subsequently trapped in an N <subscript>2</subscript> -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 (>10 <superscript>4</superscript> for DOPO) and <superscript>16</superscript> O/ <superscript>18</superscript> O (1.19 for H <superscript>18</superscript> OPO and 1.06 for HOP <superscript>18</superscript> O) in N <subscript>2</subscript> -matrices.<br /> (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)