Where is the unpaired electron density? A combined experimental and theoretical finding on the geometric and electronic structures of the Co(III) and Mn(IV) complexes of the unsymmetrical non-innocent pincer ONS ligand

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388963%3A_____%2F22%3A00563490" target="_blank" >RIV/61388963:_____/22:00563490 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61989592:15640/22:73618727

Výsledek na webu

<a href="https://doi.org/10.1039/D2DT01868C" target="_blank" >https://doi.org/10.1039/D2DT01868C</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/d2dt01868c" target="_blank" >10.1039/d2dt01868c</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Where is the unpaired electron density? A combined experimental and theoretical finding on the geometric and electronic structures of the Co(III) and Mn(IV) complexes of the unsymmetrical non-innocent pincer ONS ligand

Popis výsledku v původním jazyce

The tridentate pincer ligand [LONS]3− with the ONS donor set was generated in situ by cleaving the disulfane linkage of the pristine redox-active H4Sar(AP/AP) ligand during the complexation reaction with Co(II) and Mn(II) salts in the presence of air and Et3N. X-ray crystal structure analysis of the Co complex (1) and Mn complex (2) revealed that both the complexes were neutral in charge and six-coordinate with the meridional coordination of the two pincer [LONS]n− ligands. The Co ion was in the trivalent state, while the Mn ion was in the tetravalent state. Thus, the generated two pincer [LONS]3− ligands were non-innocent and cumulatively were in trinegative and tetranegative charges for the respective complexes. The intraligand bond distances of the coordinating ligands in each complex were similar, implying the same oxidation/electronic structure of the two ligating units. Variable-temperature magnetic susceptibility measurements revealed an S = 1/2 ground state for each complex. X-band EPR measurements unambiguously established the presence of a ligand-based unpaired electron in complex 1, and in complex 2, the unpaired electron was at the Mn centre. DFT-based theoretical calculations suggested the three-electron oxidation of the two ligating units in complex 1. Two iminosemiquinone radicals were of opposite spins (α-spin and β-spin) and a thiyl radical in either α-spin or β-spin was delocalized between two sulfur atoms. Thus, the antiferromagnetic coupling among the two opposite spins provided an S = 1/2 ground state and resulted in the radical-based EPR spectrum. In complex 2, each ligating pincer unit contained an iminosemiquinone radical that interacted antiferromagnetically with the Mn(IV)-based three unpaired electrons. This rendered a doublet ground state with the residual electron density located at the Mn center.

Název v anglickém jazyce

Where is the unpaired electron density? A combined experimental and theoretical finding on the geometric and electronic structures of the Co(III) and Mn(IV) complexes of the unsymmetrical non-innocent pincer ONS ligand

Popis výsledku anglicky

The tridentate pincer ligand [LONS]3− with the ONS donor set was generated in situ by cleaving the disulfane linkage of the pristine redox-active H4Sar(AP/AP) ligand during the complexation reaction with Co(II) and Mn(II) salts in the presence of air and Et3N. X-ray crystal structure analysis of the Co complex (1) and Mn complex (2) revealed that both the complexes were neutral in charge and six-coordinate with the meridional coordination of the two pincer [LONS]n− ligands. The Co ion was in the trivalent state, while the Mn ion was in the tetravalent state. Thus, the generated two pincer [LONS]3− ligands were non-innocent and cumulatively were in trinegative and tetranegative charges for the respective complexes. The intraligand bond distances of the coordinating ligands in each complex were similar, implying the same oxidation/electronic structure of the two ligating units. Variable-temperature magnetic susceptibility measurements revealed an S = 1/2 ground state for each complex. X-band EPR measurements unambiguously established the presence of a ligand-based unpaired electron in complex 1, and in complex 2, the unpaired electron was at the Mn centre. DFT-based theoretical calculations suggested the three-electron oxidation of the two ligating units in complex 1. Two iminosemiquinone radicals were of opposite spins (α-spin and β-spin) and a thiyl radical in either α-spin or β-spin was delocalized between two sulfur atoms. Thus, the antiferromagnetic coupling among the two opposite spins provided an S = 1/2 ground state and resulted in the radical-based EPR spectrum. In complex 2, each ligating pincer unit contained an iminosemiquinone radical that interacted antiferromagnetically with the Mn(IV)-based three unpaired electrons. This rendered a doublet ground state with the residual electron density located at the Mn center.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2022

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Dalton Transactions

ISSN

1477-9226

e-ISSN

1477-9234

Svazek periodika

51

Číslo periodika v rámci svazku

43

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

10

Strana od-do

16723-16732

Kód UT WoS článku

000872130300001

EID výsledku v databázi Scopus

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