Structural, spectroscopic and redox ...
Type de document :
Article dans une revue scientifique
DOI :
URL permanente :
Titre :
Structural, spectroscopic and redox properties of a mononuclear CoII thiolate complex – the reactivity toward S-alkylation: an experimental and theoretical study
Auteur(s) :
Gennari, Marcello [Auteur]
Département de Chimie Moléculaire - Chimie Inorganique Redox [DCM - CIRE]
Gerey, Bertrand [Auteur]
Département de Chimie Moléculaire - Chimie Inorganique Redox [DCM - CIRE]
Hall, Nikita [Auteur]
Département de Chimie Moléculaire - Chimie Inorganique Redox [DCM - CIRE]
Pécaut, Jacques [Auteur]
Vezin, Herve [Auteur]
Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516
Collomb, Marie-Noëlle [Auteur]
Département de Chimie Moléculaire - Chimie Inorganique Redox [DCM - CIRE ]
Orio, Maylis [Auteur]
Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516
duboc, carole [Auteur]
Département de Chimie Moléculaire - Chimie Inorganique Redox [DCM - CIRE]
Duboc [Auteur]
Département de Chimie Moléculaire - Chimie Inorganique Redox [DCM - CIRE]
Gerey, Bertrand [Auteur]
Département de Chimie Moléculaire - Chimie Inorganique Redox [DCM - CIRE]
Hall, Nikita [Auteur]
Département de Chimie Moléculaire - Chimie Inorganique Redox [DCM - CIRE]
Pécaut, Jacques [Auteur]
Vezin, Herve [Auteur]
Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516
Collomb, Marie-Noëlle [Auteur]
Département de Chimie Moléculaire - Chimie Inorganique Redox [DCM - CIRE ]
Orio, Maylis [Auteur]
Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516
duboc, carole [Auteur]
Département de Chimie Moléculaire - Chimie Inorganique Redox [DCM - CIRE]
Duboc [Auteur]
Titre de la revue :
Dalton Transactions
Nom court de la revue :
Dalton Trans.
Numéro :
41
Pagination :
12586-12594
Éditeur :
Royal Society of Chemistry (RSC)
Date de publication :
2012
ISSN :
1477-9234
Discipline(s) HAL :
Chimie/Chimie théorique et/ou physique
Résumé en anglais : [en]
The structural, spectroscopic, redox properties and also the reactivity toward S-alkylation of a new mononuclear N2S2 dithiolate CoII complex [CoL] (1), with H2L = 2,2′-(2,2′-bipyridine-6,6′-diyl)bis(1,1-diphenylethanethiol), ...
Lire la suite >The structural, spectroscopic, redox properties and also the reactivity toward S-alkylation of a new mononuclear N2S2 dithiolate CoII complex [CoL] (1), with H2L = 2,2′-(2,2′-bipyridine-6,6′-diyl)bis(1,1-diphenylethanethiol), have been investigated. The X-ray structure of 1 has revealed an unusual distorted square planar geometry for a CoII ion within a thiolate environment. The X-band EPR spectrum of 1 displays a rhombic S = 1/2 signal consistent with a low spin configuration for the d7 CoII ion with a large g-anisotropy (gx = 2.94, gy = 2.32 and gz = 2.01). By pulsed EPR experiments (HYSCORE), two weak hyperfine couplings (hfc) of 3.2 and 2.2 MHz have been measured and attributed respectively to protons and nitrogen nuclei of the bipyridine unit. In addition, another hyperfine coupling (hfc) of 7.5 MHz has been attributed to the cobalt ion. DFT calculations have successfully reproduced the 59Co and 14N hfc parameters. However, multiconfigurational ab initio calculations were required to predict the g-tensor of 1. The cyclic voltammogram (CV) displays two one-electron metal based processes: a quasi-reversible CoIII/CoII oxidation wave at E1/2 = −0.5 V vs. Fc+/Fc and a quasi-reversible CoII/CoI reduction wave at E1/2 = −1.7 V. 1 reacts with CH3I, generating the mono S-methylated complex, [CoLMeI] (1MeMe). The X-band EPR spectrum of 1MeMe displays a typical signal of a high spin (S = 3/2) CoII species. An optimized structure of 1MeMe, calculated by DFT, is consistent with its EPR and UV-visible spectra. Time dependent density functional theory (TD-DFT) calculations attribute the most prominent features observed in the electronic absorption spectra of 1 and 1MeMe. The singly occupied MO (SOMO) of 1 shows a notable delocalization of the unpaired electron over the metal (85%) and the ligand, especially over the sulphur atoms (10.5%), indicating a certain degree of covalency for the Co–S bonds. In 1MeMe, for two of the three SOMOs, the unpaired electron is notably delocalized over the metal (78.5 and 77.6%, respectively) and the ligand (12.5 and 7.8%, respectively over the sulphur of the thiolate function). For the third SOMO, the unpaired electron is mainly localized on the metal (92.2%). There is no electronic density spread on the sulphur atom of the thioether function in any of these SOMOs. The reactivity and the electronic properties of 1 are also compared with those of the analogous [ZnL] and [NiL] complexes.Lire moins >
Lire la suite >The structural, spectroscopic, redox properties and also the reactivity toward S-alkylation of a new mononuclear N2S2 dithiolate CoII complex [CoL] (1), with H2L = 2,2′-(2,2′-bipyridine-6,6′-diyl)bis(1,1-diphenylethanethiol), have been investigated. The X-ray structure of 1 has revealed an unusual distorted square planar geometry for a CoII ion within a thiolate environment. The X-band EPR spectrum of 1 displays a rhombic S = 1/2 signal consistent with a low spin configuration for the d7 CoII ion with a large g-anisotropy (gx = 2.94, gy = 2.32 and gz = 2.01). By pulsed EPR experiments (HYSCORE), two weak hyperfine couplings (hfc) of 3.2 and 2.2 MHz have been measured and attributed respectively to protons and nitrogen nuclei of the bipyridine unit. In addition, another hyperfine coupling (hfc) of 7.5 MHz has been attributed to the cobalt ion. DFT calculations have successfully reproduced the 59Co and 14N hfc parameters. However, multiconfigurational ab initio calculations were required to predict the g-tensor of 1. The cyclic voltammogram (CV) displays two one-electron metal based processes: a quasi-reversible CoIII/CoII oxidation wave at E1/2 = −0.5 V vs. Fc+/Fc and a quasi-reversible CoII/CoI reduction wave at E1/2 = −1.7 V. 1 reacts with CH3I, generating the mono S-methylated complex, [CoLMeI] (1MeMe). The X-band EPR spectrum of 1MeMe displays a typical signal of a high spin (S = 3/2) CoII species. An optimized structure of 1MeMe, calculated by DFT, is consistent with its EPR and UV-visible spectra. Time dependent density functional theory (TD-DFT) calculations attribute the most prominent features observed in the electronic absorption spectra of 1 and 1MeMe. The singly occupied MO (SOMO) of 1 shows a notable delocalization of the unpaired electron over the metal (85%) and the ligand, especially over the sulphur atoms (10.5%), indicating a certain degree of covalency for the Co–S bonds. In 1MeMe, for two of the three SOMOs, the unpaired electron is notably delocalized over the metal (78.5 and 77.6%, respectively) and the ligand (12.5 and 7.8%, respectively over the sulphur of the thiolate function). For the third SOMO, the unpaired electron is mainly localized on the metal (92.2%). There is no electronic density spread on the sulphur atom of the thioether function in any of these SOMOs. The reactivity and the electronic properties of 1 are also compared with those of the analogous [ZnL] and [NiL] complexes.Lire moins >
Langue :
Anglais
Comité de lecture :
Oui
Audience :
Internationale
Vulgarisation :
Non
Établissement(s) :
Université de Lille
CNRS
CNRS
Collections :
Équipe(s) de recherche :
Propriétés magnéto structurales des matériaux (PMSM)
Date de dépôt :
2021-06-17T15:34:34Z
2021-09-27T12:51:06Z
2021-09-27T12:51:06Z