Optical and infrared spectroelectrochemical studies of CN-substituted bipyridyl complexes of ruthenium(II)

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378271%3A_____%2F21%3A00539865" target="_blank" >RIV/68378271:_____/21:00539865 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61388955:_____/21:00539865 RIV/60461373:22310/21:43921907

Výsledek na webu

<a href="http://hdl.handle.net/11104/0318766" target="_blank" >http://hdl.handle.net/11104/0318766</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1021/acs.inorgchem.0c03579" target="_blank" >10.1021/acs.inorgchem.0c03579</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Optical and infrared spectroelectrochemical studies of CN-substituted bipyridyl complexes of ruthenium(II)

Popis výsledku v původním jazyce

Ruthenium(II) polypyridyl complexes [Ru(CN-Me-bpy)(x)(bpy) (3-x)](2+) (CN-Me-bpy = 4,4'-dicyano-5,5'-dimethyl-2,2'-bipyridine, bpy = 2,2'-bipyridine, and x = 1-3, abbreviated as 1(2+), 2(2+), and 3(2+)) undergo four (1(2+)) or five (2(2+) and 3(2+)) successive one-electron reduction steps between -1.3 and -2.75 V versus ferrocenium/ferrocene (Fc(+)/Fc) in tetrahydrofuran. The CN-Me-bpy ligands are reduced first, with successive one-electron reductions in 2(2+) and 3(2+) being separated by 150-210 mV. Reduction of the unsubstituted bpy ligand in 1(2+) and 2(2+) occurs only when all CN-Me-bpy ligands have been converted to their radical anions. Absorption spectra of the first three reduction products of each complex were measured across the UV, visible, near-IR (NIR), and mid-IR regions and interpreted with the help of density functional theory calculations. Reduction of the CN-Me-bpy ligand shifts the nu(C N) IR band by ca. -45 cm(-1), enhances its intensity similar to 35 times, and splits the symmetrical and antisymmetrical modes. Semireduced complexes containing two and three CN-derivatized ligands 2(+), 3(+), and 3(0) show distinct nu(C N) features due to the presence of both CN-Me-bpy and CN-Me-bpy(center dot-), confirming that each reduction is localized on a single ligand. NIR spectra of 1(0), 1(-), and 2(-) exhibit a prominent band attributable to the CN-Me-bpy(center dot-) moiety between 6000 and 7500 cm(-1), whereas bpy(center dot-)-based absorption occurs between 4500 and 6000 cm(-1), complexes 2(+), 3(+), and 3(0) also exhibit a band at ca. 3300 cm(-1) due to a CN-Me-bpy(center dot-) -> CN-Me-bpy interligand charge-transfer transition. In the UV-vis region, the decrease of pi -> pi* intraligand bands of the neutral ligands and the emergence of the corresponding bands of the radical anions are most diagnostic. The first reduction product of 1(2+) is spectroscopically similar to the lowest triplet metal-to-ligand charge-transfer excited state, which shows pronounced NIR absorption, and its nu(C N) IR band is shifted by -38 cm(-1) and 5-7-fold-enhanced relative to the ground state.

Název v anglickém jazyce

Optical and infrared spectroelectrochemical studies of CN-substituted bipyridyl complexes of ruthenium(II)

Popis výsledku anglicky

Ruthenium(II) polypyridyl complexes [Ru(CN-Me-bpy)(x)(bpy) (3-x)](2+) (CN-Me-bpy = 4,4'-dicyano-5,5'-dimethyl-2,2'-bipyridine, bpy = 2,2'-bipyridine, and x = 1-3, abbreviated as 1(2+), 2(2+), and 3(2+)) undergo four (1(2+)) or five (2(2+) and 3(2+)) successive one-electron reduction steps between -1.3 and -2.75 V versus ferrocenium/ferrocene (Fc(+)/Fc) in tetrahydrofuran. The CN-Me-bpy ligands are reduced first, with successive one-electron reductions in 2(2+) and 3(2+) being separated by 150-210 mV. Reduction of the unsubstituted bpy ligand in 1(2+) and 2(2+) occurs only when all CN-Me-bpy ligands have been converted to their radical anions. Absorption spectra of the first three reduction products of each complex were measured across the UV, visible, near-IR (NIR), and mid-IR regions and interpreted with the help of density functional theory calculations. Reduction of the CN-Me-bpy ligand shifts the nu(C N) IR band by ca. -45 cm(-1), enhances its intensity similar to 35 times, and splits the symmetrical and antisymmetrical modes. Semireduced complexes containing two and three CN-derivatized ligands 2(+), 3(+), and 3(0) show distinct nu(C N) features due to the presence of both CN-Me-bpy and CN-Me-bpy(center dot-), confirming that each reduction is localized on a single ligand. NIR spectra of 1(0), 1(-), and 2(-) exhibit a prominent band attributable to the CN-Me-bpy(center dot-) moiety between 6000 and 7500 cm(-1), whereas bpy(center dot-)-based absorption occurs between 4500 and 6000 cm(-1), complexes 2(+), 3(+), and 3(0) also exhibit a band at ca. 3300 cm(-1) due to a CN-Me-bpy(center dot-) -> CN-Me-bpy interligand charge-transfer transition. In the UV-vis region, the decrease of pi -> pi* intraligand bands of the neutral ligands and the emergence of the corresponding bands of the radical anions are most diagnostic. The first reduction product of 1(2+) is spectroscopically similar to the lowest triplet metal-to-ligand charge-transfer excited state, which shows pronounced NIR absorption, and its nu(C N) IR band is shifted by -38 cm(-1) and 5-7-fold-enhanced relative to the ground state.

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

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2021

Kód důvěrnosti údajů

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

Název periodika

Inorganic Chemistry

ISSN

0020-1669

e-ISSN

1520-510X

Svazek periodika

60

Číslo periodika v rámci svazku

6

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

10

Strana od-do

3514-3523

Kód UT WoS článku

000630142600004

EID výsledku v databázi Scopus

2-s2.0-85102963839