Search for Osme Bonds With π Systems as Electron Donors

Authors

Xin Wang, Yantai UniversityFollow
Qingzhong Li, Yantai UniversityFollow
Steve Scheiner, Utah State UniversityFollow

Document Type

Article

Author ORCID Identifier

Qingzhong Li https://orcid.org/0000-0002-0511-0167

Steve Scheiner https://orcid.org/0000-0003-0793-0369

Journal/Book Title

Molecules

Publication Date

12-22-2023

Publisher

MDPI AG

Volume

29

Issue

1

First Page

1

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.

Last Page

11

Abstract

The Osme bond is defined as pairing a Group 8 metal atom as an electron acceptor in a noncovalent interaction with a nucleophile. DFT calculations with the ωB97XD functional consider MO₄ (M = Ru, Os) as the Lewis acid, paired with a series of π electron donors C₂H₂ , C₂H₄ , C₆H₆ , C₄H₅N, C₄H₄O, and C₄H₄S. The calculations establish interaction energies in the range between 9.5 and 26.4 kJ/mol. Os engages in stronger interactions than does Ru, and those involving more extensive π-systems within the aromatic rings form stronger bonds than do the smaller ethylene and acetylene. Extensive analysis questions the existence of a true Osme bond, as the bonding chiefly involves interactions with the three O atoms of MO₄ that lie closest to the π-system, via π(C-C)→σ*(M-O) transfers. These interactions are supplemented by back donation from M-O bonds to the π*(CC) antibonding orbitals of the π-systems. Dispersion makes a large contribution to these interactions, higher than electrostatics and much greater than induction.

Recommended Citation

Wang, X.; Li, Q.; Scheiner, S. Search for Osme Bonds with π Systems as Electron Donors. Molecules 2024, 29, 79. https://doi.org/10.3390/molecules29010079