Unusual Intramolecular Motion of ReH92- in K2ReH9 Crystal: Circle Dance and Three-Arm Turnstile Mechanisms Revealed by Computational Studies

Yunwen Tao; Xianlong Wang; Wenli Zou; Geng-Geng Luo; Elfi Kraka

doi:10.1021/acs.inorgchem.1c03118

Unusual Intramolecular Motion of ReH₉^2- in K₂ReH₉ Crystal: Circle Dance and Three-Arm Turnstile Mechanisms Revealed by Computational Studies

Inorg Chem. 2022 Jan 17;61(2):1041-1050. doi: 10.1021/acs.inorgchem.1c03118. Epub 2021 Dec 29.

Authors

Yunwen Tao¹, Xianlong Wang^{2

3}, Wenli Zou⁴, Geng-Geng Luo⁵, Elfi Kraka¹

Affiliations

¹ Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, Texas 75275-0314, United States.
² Department of Bioinformatics, School of Medical Technology and Engineering, Key Laboratory of Medical Bioinformatics, Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Fujian Medical University, Fuzhou 350122, P. R. China.
³ School and Hospital of Stomatology, Fujian Medical University, Fuzhou 350002, P. R. China.
⁴ Institute of Modern Physics, Northwest University, and Shaanxi Key Laboratory for Theoretical Physics Frontiers, Xi'an, Shaanxi 710127, P. R. China.
⁵ Key Laboratory of Environmental Friendly Function Materials, Ministry of Education, and College of Materials Science and Engineering, Huaqiao University, Xiamen, Fujian 361021, P. R. China.

PMID: 34965110
DOI: 10.1021/acs.inorgchem.1c03118

Abstract

The nonahydridorhenate dianion ReH₉^2- is a unique rhenium polyhydride complex due to its remarkably high coordination number; however, its detailed polytopal rearrangement process in either solution or crystal is so far unclear. In this work, our quantum chemical calculations have identified two previously unreported fluxional mechanisms for the ReH₉^2- dianion in the K₂ReH₉ crystal: three-arm turnstile rotation and circle dance mechanism. These two polytopal rearrangements in the crystal offer an alternative interpretation to the pulse and wide-line NMR spectra (Farrar et al. J. Chem. Phys. 1969, 51, 3595). The previously postulated hindered rotation of the whole ReH₉^2- dianion in K₂ReH₉ (White et al. J. Chem. Soc., Faraday Trans. 2 1972, 68, 1414) turns out to be a combination of the above-mentioned two elementary fluxional processes. In addition, our calculations have confirmed the Muetterties' D_3h⇌C_4v rearrangement as the intramolecular motion for the ReH₉^2- dianion in solution.