Local force constants and charges of the nitrosyl ligand in photoinduced NO linkage isomers in a prototypical ruthenium nitrosyl complex

Artem A Mikhailov; Axel Gansmüller; Krzysztof A Konieczny; Sébastien Pillet; Gennadiy Kostin; Peter Klüfers; Theo Woike; Dominik Schaniel

doi:10.1039/d4cp01374c

Local force constants and charges of the nitrosyl ligand in photoinduced NO linkage isomers in a prototypical ruthenium nitrosyl complex

Phys Chem Chem Phys. 2024 May 29;26(21):15255-15267. doi: 10.1039/d4cp01374c.

Authors

Artem A Mikhailov¹, Axel Gansmüller¹, Krzysztof A Konieczny^{1

2}, Sébastien Pillet¹, Gennadiy Kostin³, Peter Klüfers⁴, Theo Woike¹, Dominik Schaniel¹

Affiliations

¹ Université de Lorraine, CNRS, CRM2, 54000 Nancy, France. artem.mikhailov@univ-lorraine.fr.
² Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.
³ Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Science, Novosibirsk 630090, Russia.
⁴ Department of Chemistry, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, München 81377, Germany.

PMID: 38751356
DOI: 10.1039/d4cp01374c

Abstract

Photoinduced linkage isomers (PLI) of the NO ligand in transition-metal nitrosyl compounds can be identified by vibrational spectroscopy due to the large shifts of the (NO) stretching vibration. We present a detailed experimental and theoretical study of the prototypical compound K₂[RuCl₅NO], where (NO) shifts by ≈150 cm^-1 when going from the N-bound (κN) ground state (GS) to the oxygen-bound (κO) metastable linkage isomer MS1, and by ≈360 cm^-1 when going to the side-on (κ²N,O) metastable linkage isomer MS2. We show that the experimentally observed N-O stretching modes of the GS, MS1, and MS2 exhibit strong coupling with the Ru-N and Ru-O stretching modes, which can be decoupled using the local mode vibrational theory formalism. From the resulting decoupled pure two-atomic harmonic oscillators the local force constants are determined, which all follow the same quadratic behavior on the wavenumber. A Bader charge analysis shows that the total charge on the NO ligand is not correlated to the observed frequency shift of (NO).