On Librational and Rotational Motions of Aromatic Rings in Layered Sn(IV) and Zr(IV) Phosphonate Materials: A Variable-Temperature 13C, 31P Solid-State NMR Study

Vladimir I Bakhmutov; Douglas W Elliott; Aida Contreras-Ramirez; Abraham Clearfield; Hong-Cai Zhou

doi:10.1021/acs.jpclett.0c01173

On Librational and Rotational Motions of Aromatic Rings in Layered Sn(IV) and Zr(IV) Phosphonate Materials: A Variable-Temperature ¹³C, ³¹P Solid-State NMR Study

J Phys Chem Lett. 2020 Jul 2;11(13):4958-4961. doi: 10.1021/acs.jpclett.0c01173. Epub 2020 Jun 10.

Authors

Vladimir I Bakhmutov¹, Douglas W Elliott¹, Aida Contreras-Ramirez¹, Abraham Clearfield¹, Hong-Cai Zhou^{1

2}

Affiliations

¹ Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States.
² Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843-3003, United States.

PMID: 32496774
DOI: 10.1021/acs.jpclett.0c01173

Abstract

According to the solid-state ¹³C, ³¹P NMR study and ¹³C chemical shift anisotropy (CSA) measurements, aromatic rings in the layered metal(IV) phosphonate materials behave as low-energy rotors at rotation activation energy, E_act, of 1.4-3.0 kcal/mol. The rotational mechanism consists of 180° flips and librations around C(1)-C(4) axis. The amplitude of the librations, added to the flips, grows with temperature, shifting the reorientations toward rotational diffusion at high temperatures.