Experimental and computational tuning of metalla-N-heterocyclic carbenes at palladium(II) and platinum(II) centers


Kashina, Maria V, Luzyanin, Konstantin V ORCID: 0000-0001-9312-7139, Katlenok, Eugene A, Novikov, Alexander S and Kinzhalov, Mikhail A (2022) Experimental and computational tuning of metalla-N-heterocyclic carbenes at palladium(II) and platinum(II) centers. DALTON TRANSACTIONS, 51 (17). pp. 6718-6734.

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Abstract

Palladium(II) and platinum(II) complexes featuring metalla-N-heterocyclic carbenes (7-12) were synthesised <i>via</i> metal-mediated coupling between equimolar <i>cis</i>-[MCl<sub>2</sub>(CNR)<sub>2</sub>] (R = 2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub> (Xyl), 2,4,6-Me<sub>3</sub>C<sub>6</sub>H<sub>3</sub> (Mes)) and 2-aminopyridine or 2-aminopyrazine. Thiocyanate complexes 13-18 with two thiocyanate ligands were obtained through the ligand exchange in the parent compounds 7-12 with NH<sub>4</sub>CNS in acetone/CH<sub>2</sub>Cl<sub>2</sub>. Complexes 7-18 were isolated and characterised by HRESI<sup>+</sup>-MS, IR, <sup>1</sup>H and <sup>13</sup>C{<sup>1</sup>H} NMR spectroscopy and single-crystal X-ray diffraction (in the case of 11, 16, and 18). The UV-vis properties of 7-18 and the electrochemical properties of 7-12 were also evaluated. To study the electronic structure and bonding nature in the new compounds, the quantum theory of atoms in molecules (QTAIM) and Mayer bond order analysis together with the extended transition state with the natural orbitals for chemical valence (ETS-NOCV) method, were used. X-ray diffraction studies and theoretical considerations indicate that the thiocyanate derivatives 16 and 18 form supramolecular dimers by two symmetrical pairs M<sup>1</sup>⋯C<sup>5</sup> and S<sup>1</sup>⋯C<sup>2</sup> with short intermolecular contacts between an electron-rich M<sup>II</sup>-center and thiocyanate ligand on the one side and the electron-poor π-system of an azaheterocyclic ring on the other side. Representative carbenes 8, 11 and 12 were evaluated as photocatalysts for the hydrosilylation of diphenylacetylene with triethylsilane giving 1,2-(diphenylvinyl)triethylsilane in 98% yield under visible light irradiation (blue light, 445 nm).

Item Type: Article
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 08 Jun 2022 14:13
Last Modified: 14 Mar 2023 02:30
DOI: 10.1039/d2dt00252c
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3155410
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