Didier Astruc - Academia.edu (original) (raw)
Papers by Didier Astruc
Journal of Proteome Research, Dec 28, 2016
Thorough characterization of toxic effects of nanoparticles (NP) is desirable due to the increasi... more Thorough characterization of toxic effects of nanoparticles (NP) is desirable due to the increasing risk of potential environmental contamination by NP. In the current study, we combined three recently developed proteomics approaches to assess the effects of Au, CuO, and CdTe NP on the innate immune system. The human monocyte cell line THP-1 was employed as a model. The anticancer drugs camptothecin and doxorubicin were used as positive controls for cell death and lipopolysaccharide was chosen as a positive control for pro-inflammatory activation. Despite equivalent overall toxicity effect (50±10% dead cells), the three NP induced distinctly different proteomics signatures, with the strongest effect being induced by CdTe NP, followed by CuO and gold NP. The CdTe toxicity mechanism involves down-regulation of topoisomerases. The effect of CuO NP is most reminiscent of oxidative stress, and involves upregulation of proteins involved in heat response. The gold NP induced up-regulation of the inflammatory mediator, NF-κB, and its inhibitor TIPE2 was identified as a direct target of gold NP. Furthermore, gold NP triggered activation of NF-κB as evidenced by phosphorylation of the p65 subunit. Overall, the combined proteomics approach described here can be used to characterize the effects of NP on immune cells.
Chemical Communications, 2008
ChemInform, Apr 8, 2008
ChemInform Abstract Durch einen Anionenaustauscher in Boranatform (II) wird Diphenyldiselenid (II... more ChemInform Abstract Durch einen Anionenaustauscher in Boranatform (II) wird Diphenyldiselenid (III) zum polymergebundenen Ammonium-phenylselenid (IV) reduziert und zu Seleniden (VI) bzw. Acetylselenid (VII) umgesetzt. (NMR-Daten).
Springer eBooks, 1995
A novel hexafunctional initiator C6[(CH2)2p-C6H4CH(Cl)Me]6 has been purposely synthesized to subs... more A novel hexafunctional initiator C6[(CH2)2p-C6H4CH(Cl)Me]6 has been purposely synthesized to subsequently serve in the cationic polymerization of styrene. This initiator is prepared via Fe(ŋ-C5H5)+ mediated perbenzylation of hexamethylbenzene, followed by regiospecific acetylation, reduction and chlorination of outer phenyl rings. The polystyrene stars which are obtained in the presence of this initiator exhibit narrow molecular weight distribution (MWD) and a precise functionality of 6. Because the cationic polymerization of styrene is not totally free of side reactions, such as s-proton elimination of growing carbeniums, the upper limit of the molecular weight control for these star polymers is the range of Mn ~30000 g/mole.
Acs Symposium Series, Dec 1, 2005
Giant dendrimers were constructed using generations consisting in two reactions: hydroelementatio... more Giant dendrimers were constructed using generations consisting in two reactions: hydroelementation followed by a nucleophilic reaction of a phenoltriallyl brick. After having synthesized a third-generation dendrimer usinghydroboration with disiamylborane, our group switched to Karsted-catalyzed hydrosilylation with dimethylchloromethylsilane. This successfully led us to the 9 t h generation (> 10 5 tethers) without being marred by the bulk problem at the dendrimer periphery. This construction was achieved far beyond the de Gennes "dense-packing" limit, indicating that the extremities of the tethers must back fold towards the core. Thus, the construction must be limited by the volume rather than surface.
Coordination Chemistry Reviews, Jun 1, 2016
This review is focused on the mechanistic aspects and recent trends of the metalcatalyzed azide-a... more This review is focused on the mechanistic aspects and recent trends of the metalcatalyzed azide-alkyne cycloaddition (MAAC) so-called "click" reactions with catalysts based on various metals (Cu, Ru, Ag, Au, Ir, Ni, Zn, Ln), although Cu (I) catalysts are still the most used ones. These MAAC reactions are by far the most common click reactions relevant to the "green chemistry" concept. First developed by the Fokin-Sharpless and Meldal group with Cu(I) in 2002, they have then been extended to Ru(II) catalysts by the Fokin group in 2005 and finally to many other metal catalysts. Mechanistic investigations are essential to reaction improvements and subsequent applications, and indeed as shown in this review the proposed mechanisms have been multiple during the last decade based on theoretical computations and experimental search of intermediates. New trends (since 2012) are also presented here often representing both exciting approaches for various applications and new challenges for further mechanistic investigations.
Journal of the American Chemical Society, 2021
The promising field of nanomedicine stimulates a continuous search for multifunctional nanotheran... more The promising field of nanomedicine stimulates a continuous search for multifunctional nanotheranostic systems for imaging and drug delivery. Herein, we demonstrate that application of supramolecular chemistry's concepts in dendritic assemblies can enable the formation of advanced dendrimer-based nanotheranostic devices. A dendrimer bearing 81 triazolylferrocenyl terminal groups adopts a more compact shell-like structure in polar solvents with the ferrocenyl peripheral groups backfolding toward the hydrophobic dendrimer interior, while exposing the more polar triazole moieties as the dendritic shell. Akin to lipids, the compact dendritic structure self-assembles into uniform nanovesicles that in turn self-assemble into larger vesosomes in water. The vesosomes emit green nontraditional intrinsic fluorescence (NTIL), which is an emerging property as there are no classical fluorophores in the dendritic macromolecular structure. This work confirms the hypothesis that the NTIL emission is greatly enhanced by rigidification of the supramolecular assemblies containing heteroatomic subluminophores (HASLs) and by the presence of electron rich functional groups on the periphery of dendrimers. This work is the first one detecting NTIL in ferrocenyl-terminated dendrimers. Moreover, the vesosomes are stable in biological medium, are uptaken by cells, and show cytotoxic activity against cancer cells. Accordingly, the self-organization of these dendrimers into tertiary structures promotes the emergence of new properties enabling the same component, in this case, ferrocenyl group, to function as both antitumoral drug and fluorophore.
Angewandte Chemie International Edition, 2021
The first all‐metallocene rechargeable battery consisting of poly‐cobaltocenium/‐ and poly‐ferroc... more The first all‐metallocene rechargeable battery consisting of poly‐cobaltocenium/‐ and poly‐ferrocene/reduced graphene oxide composites as anode and cathode was prepared. The intrinsically fast ET self‐exchange rate of metallocenes was successfully combined with an efficient ion‐percolation achieved by molecular self‐assembly. The resulting battery materials show ideal Nernstian behavior, is thickness scalable up to >1.2 C cm−2, and exhibit high coulombic efficiency at ultrafast rates (200 A g−1). Using aqueous LiClO4, the charge is carried exclusively by the anion. The ClO4− intercalation is accompanied by a reciprocal height change of the active layers. Principally, volume changes in organic battery materials during charging/discharging are not desirable and represent a major safety issue. However, here, the individual height changes—due to ion breathing—are reciprocal and thus prohibiting any internal pressure build‐up in the closed‐cell, leading to excellent cycling stability.
Chemistry – A European Journal, 2020
The electronic structure of the spherical Mackay icosahedral nanosized cluster Pd55(PiPr3)12(μ3‐C... more The electronic structure of the spherical Mackay icosahedral nanosized cluster Pd55(PiPr3)12(μ3‐CO)20 is analyzed by using DFT calculations. Results reveal that it can be considered as a regular superatom with a “magic” electron count of 20, characterized by a 1S2 1P6 1D10 2S2 jellium configuration. Its open shell nature is associated with partial occupation of non‐jellium, 4d‐type, levels located on the interior of the Pd55 kernel. This shows that the superatom model can be used to rationalize the bonding and stability of spherical ligated group 10 clusters, despite their apparent 0‐electron count.
Scientific Reports, 2019
Systems biology is increasingly being applied in nanosafety research for observing and predicting... more Systems biology is increasingly being applied in nanosafety research for observing and predicting the biological perturbations inflicted by exposure to nanoparticles (NPs). In the present study, we used a combined transcriptomics and proteomics approach to assess the responses of human monocytic cells to Au-NPs of two different sizes with three different surface functional groups, i.e., alkyl ammonium bromide, alkyl sodium carboxylate, or poly(ethylene glycol) (PEG)-terminated Au-NPs. Cytotoxicity screening using THP-1 cells revealed a pronounced cytotoxicity for the ammonium-terminated Au-NPs, while no cell death was seen after exposure to the carboxylated or PEG-modified Au-NPs. Moreover, Au-NR3+ NPs, but not the Au-COOH NPs, were found to trigger dose-dependent lethality in vivo in the model organism, Caenorhabditis elegans. RNA sequencing combined with mass spectrometry-based proteomics predicted that the ammonium-modified Au-NPs elicited mitochondrial dysfunction. The latter re...
ACH - Models in Chemistry
ABSTRACT
Le Journal de Physique Colloques, 1988
Bi-iron electron reservoirs complexes, of sandwich structure, have been studied in the 36, 37, 38... more Bi-iron electron reservoirs complexes, of sandwich structure, have been studied in the 36, 37, 38 estates , by MGssbauer spectroscopy in external magnetic fields. The nature of the various couplings between the 19 e-subunits has been elucidated, and correlated to the electron transfer to the bridge in the mixed valence state.
Journal of the Chemical Society, Chemical Communications, 1988
... Christian Amatore,*= Jean-Noel Verpeaux,a Alex Madonik,b Marie-Helene Desbois,c and Didier As... more ... Christian Amatore,*= Jean-Noel Verpeaux,a Alex Madonik,b Marie-Helene Desbois,c and Didier Astruc*C a Ecole Normale Superieure, UA CNRS No I I I0 &#x27;Activation Moleculaire, Laboratoire de Chimie, 24, rue ... Chem., 1972,76,2439; MG Richmond and JK Kochi, Znorg. ...
Advances in Dendritic Macromolecules Volume 5, 2002
Organometallic Syntheses, 1988
Organometallics, 1992
Decamethylbimetallocenes have been synhesized for Fe, Co, and Rh, and the crystal structures of t... more Decamethylbimetallocenes have been synhesized for Fe, Co, and Rh, and the crystal structures of the 36-electron iron and rhodium complexes show a fully bridging ligand, which results in considerable mutual inflUenCe of the two transition-metal centers.'-' For in-* Universitat-GH, Essen.
Organometallics, 1988
Page 1. Organometallics 1988, 7, 2253-2255 2253 (Fuivaiene)diiron Chemistry: Bis Piano-Stool Comp... more Page 1. Organometallics 1988, 7, 2253-2255 2253 (Fuivaiene)diiron Chemistry: Bis Piano-Stool Complexes and Thelr Redox Properties Marc Lacoste,+ Didler Astruc, *#+ Marie-ThOrke Garland,$ and Franqols Varret§ Laboratoire ...
![Research paper thumbnail of First 17−18−19-Electron Triads of Stable Isostructural Organometallic Complexes. The 17-Electron Complexes [Fe(C5R5)(arene)]2+ (R = H or Me), a Novel Family of Strong Oxidants: Isolation, Characterization, Electronic Structure, and Redox Properties](https://attachments.academia-assets.com/109110919/thumbnails/1.jpg)
](Journal of the American Chemical Society, 1998
The 18-electron complexes [M II (C 5 R 5)(arene)] + (M) Fe: R) H or Me, arene) C 6 H 6-n Me n (n)... more The 18-electron complexes [M II (C 5 R 5)(arene)] + (M) Fe: R) H or Me, arene) C 6 H 6-n Me n (n) 0-6), C 6 H 5 NMe 2 , or C 6 Me 5 NH 2 ; M) Ru: R) Me, arene) C 6 Me 6) are oxidized to M III complexes between 0.92 and 1.70 V vs [FeCp 2 ] according to a single-electron process that is reversible in SO 2 if at least one of the rings is permethylated. The dinuclear complex [Fe II 2 (fulvalenyl)(C 6 Me 6)][PF 6 ] 2 is oxidized in two one-electron reversible waves in SO 2 separated by 0.38 V to the mixed-valence species trication and to the 34-electron dioxidized tetracation. Stoichiometric oxidation of the yellow complexes [Fe II Cp*(arene)][EX 6 ] (EX 6) PF 6 or SbCl 6) is achieved by using SbCl 5 in CH 2 Cl 2 at 20°C or SbF 5 in SO 2 at-10°C or by Br 2 + [Ag][SbF 6 ] and gives the purple 17-electron complexes [Fe III Cp*(arene)][SbX 6 ] 2 (X) F or Cl) if arene) hexa-, penta-, and 1,2,4,5-tetramethylbenzene. No oxidation is observed for complexes of less methylated arene ligands, which shows that the oxidation power of SbX 5 is limited to 1.0 V Vs [FeCp 2 ] for monocations. The complex [Fe III Cp*(C 6 Me 6)][SbCl 6 ] 2 , 1[SbCl 6 ] 2 , is also obtained by SbCl 5 oxidation of the 19-electron complex [Fe I Cp*(C 6 Me 6)], 1, at-80°C. The 17-electron complexes are characterized by elemental analyses, ESR, Mössbauer, and UV/vis spectra, magnetic susceptibility, cyclic voltammetry, and quantitative singleelectron reduction by ferrocene. The complex 1[SbCl 6 ] 2 is used as a very strong single-electron oxidant to also oxidize [Ru(bpy) 3 ][PF 6 ] 2 to the 17-electron Ru III species and the neutral cluster [FeCp(µ 3-CO)] 4 to its mono-and dications. The complex [Fe II Cp(C 6 Me 6)][PF 6 ] is a redox catalyst for the anodic oxidation of furfural on Pt in SO 2 via the Fe II /Fe III redox system. Density functional theory (DFT) calculations on various 17electron compounds [Fe(C 5 R 5)(C 6 R 6)] +/2+ (R) H, Me) and [FeCp(C 6 H 5 NH 2)] 2+ , as well as on the isoelectronic complexes ferrocenium and [Fe(C 6 H 6) 2 ] 3+ and their 18-electron parents, allowed a detailed comparison of the electronic structure, bonding, UV-visible spectra, and ionization potentials of these species. Although the nature of the HOMO is not always the same within the series of their 18-electron parents, all the computed 17-electron complexes have the same 2 E 2 ground state corresponding to the metallic (a 1) 2 (e 2) 3 electron configuration. Full geometry optimizations lead to the prediction of their molecular structures for the lowest 2 E 2 and 1 A 1 states.
Hyperfine Interactions, 1986
A Mössbauer study of two mixed-valence FeIIFeI compounds C5H5Fe(C5H4)2 FeC6(CH3)6 (1) and ¦C6(CH3... more A Mössbauer study of two mixed-valence FeIIFeI compounds C5H5Fe(C5H4)2 FeC6(CH3)6 (1) and ¦C6(CH3)6 Fe(C5H4)2 Fe C6(CH3)6¦+ (2+) was carried out from 4.2K to room temperature. Zero-field spectra show two types of iron atoms for1 and one type for2+. Hence1 is a localized mixed-valence complex and2+ a delocalized mixed-valence complexe. High magnetic field spectra for 2+ give a negative sign for
Journal of Proteome Research, Dec 28, 2016
Thorough characterization of toxic effects of nanoparticles (NP) is desirable due to the increasi... more Thorough characterization of toxic effects of nanoparticles (NP) is desirable due to the increasing risk of potential environmental contamination by NP. In the current study, we combined three recently developed proteomics approaches to assess the effects of Au, CuO, and CdTe NP on the innate immune system. The human monocyte cell line THP-1 was employed as a model. The anticancer drugs camptothecin and doxorubicin were used as positive controls for cell death and lipopolysaccharide was chosen as a positive control for pro-inflammatory activation. Despite equivalent overall toxicity effect (50±10% dead cells), the three NP induced distinctly different proteomics signatures, with the strongest effect being induced by CdTe NP, followed by CuO and gold NP. The CdTe toxicity mechanism involves down-regulation of topoisomerases. The effect of CuO NP is most reminiscent of oxidative stress, and involves upregulation of proteins involved in heat response. The gold NP induced up-regulation of the inflammatory mediator, NF-κB, and its inhibitor TIPE2 was identified as a direct target of gold NP. Furthermore, gold NP triggered activation of NF-κB as evidenced by phosphorylation of the p65 subunit. Overall, the combined proteomics approach described here can be used to characterize the effects of NP on immune cells.
Chemical Communications, 2008
ChemInform, Apr 8, 2008
ChemInform Abstract Durch einen Anionenaustauscher in Boranatform (II) wird Diphenyldiselenid (II... more ChemInform Abstract Durch einen Anionenaustauscher in Boranatform (II) wird Diphenyldiselenid (III) zum polymergebundenen Ammonium-phenylselenid (IV) reduziert und zu Seleniden (VI) bzw. Acetylselenid (VII) umgesetzt. (NMR-Daten).
Springer eBooks, 1995
A novel hexafunctional initiator C6[(CH2)2p-C6H4CH(Cl)Me]6 has been purposely synthesized to subs... more A novel hexafunctional initiator C6[(CH2)2p-C6H4CH(Cl)Me]6 has been purposely synthesized to subsequently serve in the cationic polymerization of styrene. This initiator is prepared via Fe(ŋ-C5H5)+ mediated perbenzylation of hexamethylbenzene, followed by regiospecific acetylation, reduction and chlorination of outer phenyl rings. The polystyrene stars which are obtained in the presence of this initiator exhibit narrow molecular weight distribution (MWD) and a precise functionality of 6. Because the cationic polymerization of styrene is not totally free of side reactions, such as s-proton elimination of growing carbeniums, the upper limit of the molecular weight control for these star polymers is the range of Mn ~30000 g/mole.
Acs Symposium Series, Dec 1, 2005
Giant dendrimers were constructed using generations consisting in two reactions: hydroelementatio... more Giant dendrimers were constructed using generations consisting in two reactions: hydroelementation followed by a nucleophilic reaction of a phenoltriallyl brick. After having synthesized a third-generation dendrimer usinghydroboration with disiamylborane, our group switched to Karsted-catalyzed hydrosilylation with dimethylchloromethylsilane. This successfully led us to the 9 t h generation (> 10 5 tethers) without being marred by the bulk problem at the dendrimer periphery. This construction was achieved far beyond the de Gennes "dense-packing" limit, indicating that the extremities of the tethers must back fold towards the core. Thus, the construction must be limited by the volume rather than surface.
Coordination Chemistry Reviews, Jun 1, 2016
This review is focused on the mechanistic aspects and recent trends of the metalcatalyzed azide-a... more This review is focused on the mechanistic aspects and recent trends of the metalcatalyzed azide-alkyne cycloaddition (MAAC) so-called "click" reactions with catalysts based on various metals (Cu, Ru, Ag, Au, Ir, Ni, Zn, Ln), although Cu (I) catalysts are still the most used ones. These MAAC reactions are by far the most common click reactions relevant to the "green chemistry" concept. First developed by the Fokin-Sharpless and Meldal group with Cu(I) in 2002, they have then been extended to Ru(II) catalysts by the Fokin group in 2005 and finally to many other metal catalysts. Mechanistic investigations are essential to reaction improvements and subsequent applications, and indeed as shown in this review the proposed mechanisms have been multiple during the last decade based on theoretical computations and experimental search of intermediates. New trends (since 2012) are also presented here often representing both exciting approaches for various applications and new challenges for further mechanistic investigations.
Journal of the American Chemical Society, 2021
The promising field of nanomedicine stimulates a continuous search for multifunctional nanotheran... more The promising field of nanomedicine stimulates a continuous search for multifunctional nanotheranostic systems for imaging and drug delivery. Herein, we demonstrate that application of supramolecular chemistry's concepts in dendritic assemblies can enable the formation of advanced dendrimer-based nanotheranostic devices. A dendrimer bearing 81 triazolylferrocenyl terminal groups adopts a more compact shell-like structure in polar solvents with the ferrocenyl peripheral groups backfolding toward the hydrophobic dendrimer interior, while exposing the more polar triazole moieties as the dendritic shell. Akin to lipids, the compact dendritic structure self-assembles into uniform nanovesicles that in turn self-assemble into larger vesosomes in water. The vesosomes emit green nontraditional intrinsic fluorescence (NTIL), which is an emerging property as there are no classical fluorophores in the dendritic macromolecular structure. This work confirms the hypothesis that the NTIL emission is greatly enhanced by rigidification of the supramolecular assemblies containing heteroatomic subluminophores (HASLs) and by the presence of electron rich functional groups on the periphery of dendrimers. This work is the first one detecting NTIL in ferrocenyl-terminated dendrimers. Moreover, the vesosomes are stable in biological medium, are uptaken by cells, and show cytotoxic activity against cancer cells. Accordingly, the self-organization of these dendrimers into tertiary structures promotes the emergence of new properties enabling the same component, in this case, ferrocenyl group, to function as both antitumoral drug and fluorophore.
Angewandte Chemie International Edition, 2021
The first all‐metallocene rechargeable battery consisting of poly‐cobaltocenium/‐ and poly‐ferroc... more The first all‐metallocene rechargeable battery consisting of poly‐cobaltocenium/‐ and poly‐ferrocene/reduced graphene oxide composites as anode and cathode was prepared. The intrinsically fast ET self‐exchange rate of metallocenes was successfully combined with an efficient ion‐percolation achieved by molecular self‐assembly. The resulting battery materials show ideal Nernstian behavior, is thickness scalable up to >1.2 C cm−2, and exhibit high coulombic efficiency at ultrafast rates (200 A g−1). Using aqueous LiClO4, the charge is carried exclusively by the anion. The ClO4− intercalation is accompanied by a reciprocal height change of the active layers. Principally, volume changes in organic battery materials during charging/discharging are not desirable and represent a major safety issue. However, here, the individual height changes—due to ion breathing—are reciprocal and thus prohibiting any internal pressure build‐up in the closed‐cell, leading to excellent cycling stability.
Chemistry – A European Journal, 2020
The electronic structure of the spherical Mackay icosahedral nanosized cluster Pd55(PiPr3)12(μ3‐C... more The electronic structure of the spherical Mackay icosahedral nanosized cluster Pd55(PiPr3)12(μ3‐CO)20 is analyzed by using DFT calculations. Results reveal that it can be considered as a regular superatom with a “magic” electron count of 20, characterized by a 1S2 1P6 1D10 2S2 jellium configuration. Its open shell nature is associated with partial occupation of non‐jellium, 4d‐type, levels located on the interior of the Pd55 kernel. This shows that the superatom model can be used to rationalize the bonding and stability of spherical ligated group 10 clusters, despite their apparent 0‐electron count.
Scientific Reports, 2019
Systems biology is increasingly being applied in nanosafety research for observing and predicting... more Systems biology is increasingly being applied in nanosafety research for observing and predicting the biological perturbations inflicted by exposure to nanoparticles (NPs). In the present study, we used a combined transcriptomics and proteomics approach to assess the responses of human monocytic cells to Au-NPs of two different sizes with three different surface functional groups, i.e., alkyl ammonium bromide, alkyl sodium carboxylate, or poly(ethylene glycol) (PEG)-terminated Au-NPs. Cytotoxicity screening using THP-1 cells revealed a pronounced cytotoxicity for the ammonium-terminated Au-NPs, while no cell death was seen after exposure to the carboxylated or PEG-modified Au-NPs. Moreover, Au-NR3+ NPs, but not the Au-COOH NPs, were found to trigger dose-dependent lethality in vivo in the model organism, Caenorhabditis elegans. RNA sequencing combined with mass spectrometry-based proteomics predicted that the ammonium-modified Au-NPs elicited mitochondrial dysfunction. The latter re...
ACH - Models in Chemistry
ABSTRACT
Le Journal de Physique Colloques, 1988
Bi-iron electron reservoirs complexes, of sandwich structure, have been studied in the 36, 37, 38... more Bi-iron electron reservoirs complexes, of sandwich structure, have been studied in the 36, 37, 38 estates , by MGssbauer spectroscopy in external magnetic fields. The nature of the various couplings between the 19 e-subunits has been elucidated, and correlated to the electron transfer to the bridge in the mixed valence state.
Journal of the Chemical Society, Chemical Communications, 1988
... Christian Amatore,*= Jean-Noel Verpeaux,a Alex Madonik,b Marie-Helene Desbois,c and Didier As... more ... Christian Amatore,*= Jean-Noel Verpeaux,a Alex Madonik,b Marie-Helene Desbois,c and Didier Astruc*C a Ecole Normale Superieure, UA CNRS No I I I0 &#x27;Activation Moleculaire, Laboratoire de Chimie, 24, rue ... Chem., 1972,76,2439; MG Richmond and JK Kochi, Znorg. ...
Advances in Dendritic Macromolecules Volume 5, 2002
Organometallic Syntheses, 1988
Organometallics, 1992
Decamethylbimetallocenes have been synhesized for Fe, Co, and Rh, and the crystal structures of t... more Decamethylbimetallocenes have been synhesized for Fe, Co, and Rh, and the crystal structures of the 36-electron iron and rhodium complexes show a fully bridging ligand, which results in considerable mutual inflUenCe of the two transition-metal centers.'-' For in-* Universitat-GH, Essen.
Organometallics, 1988
Page 1. Organometallics 1988, 7, 2253-2255 2253 (Fuivaiene)diiron Chemistry: Bis Piano-Stool Comp... more Page 1. Organometallics 1988, 7, 2253-2255 2253 (Fuivaiene)diiron Chemistry: Bis Piano-Stool Complexes and Thelr Redox Properties Marc Lacoste,+ Didler Astruc, *#+ Marie-ThOrke Garland,$ and Franqols Varret§ Laboratoire ...
Journal of the American Chemical Society, 1998
The 18-electron complexes [M II (C 5 R 5)(arene)] + (M) Fe: R) H or Me, arene) C 6 H 6-n Me n (n)... more The 18-electron complexes [M II (C 5 R 5)(arene)] + (M) Fe: R) H or Me, arene) C 6 H 6-n Me n (n) 0-6), C 6 H 5 NMe 2 , or C 6 Me 5 NH 2 ; M) Ru: R) Me, arene) C 6 Me 6) are oxidized to M III complexes between 0.92 and 1.70 V vs [FeCp 2 ] according to a single-electron process that is reversible in SO 2 if at least one of the rings is permethylated. The dinuclear complex [Fe II 2 (fulvalenyl)(C 6 Me 6)][PF 6 ] 2 is oxidized in two one-electron reversible waves in SO 2 separated by 0.38 V to the mixed-valence species trication and to the 34-electron dioxidized tetracation. Stoichiometric oxidation of the yellow complexes [Fe II Cp*(arene)][EX 6 ] (EX 6) PF 6 or SbCl 6) is achieved by using SbCl 5 in CH 2 Cl 2 at 20°C or SbF 5 in SO 2 at-10°C or by Br 2 + [Ag][SbF 6 ] and gives the purple 17-electron complexes [Fe III Cp*(arene)][SbX 6 ] 2 (X) F or Cl) if arene) hexa-, penta-, and 1,2,4,5-tetramethylbenzene. No oxidation is observed for complexes of less methylated arene ligands, which shows that the oxidation power of SbX 5 is limited to 1.0 V Vs [FeCp 2 ] for monocations. The complex [Fe III Cp*(C 6 Me 6)][SbCl 6 ] 2 , 1[SbCl 6 ] 2 , is also obtained by SbCl 5 oxidation of the 19-electron complex [Fe I Cp*(C 6 Me 6)], 1, at-80°C. The 17-electron complexes are characterized by elemental analyses, ESR, Mössbauer, and UV/vis spectra, magnetic susceptibility, cyclic voltammetry, and quantitative singleelectron reduction by ferrocene. The complex 1[SbCl 6 ] 2 is used as a very strong single-electron oxidant to also oxidize [Ru(bpy) 3 ][PF 6 ] 2 to the 17-electron Ru III species and the neutral cluster [FeCp(µ 3-CO)] 4 to its mono-and dications. The complex [Fe II Cp(C 6 Me 6)][PF 6 ] is a redox catalyst for the anodic oxidation of furfural on Pt in SO 2 via the Fe II /Fe III redox system. Density functional theory (DFT) calculations on various 17electron compounds [Fe(C 5 R 5)(C 6 R 6)] +/2+ (R) H, Me) and [FeCp(C 6 H 5 NH 2)] 2+ , as well as on the isoelectronic complexes ferrocenium and [Fe(C 6 H 6) 2 ] 3+ and their 18-electron parents, allowed a detailed comparison of the electronic structure, bonding, UV-visible spectra, and ionization potentials of these species. Although the nature of the HOMO is not always the same within the series of their 18-electron parents, all the computed 17-electron complexes have the same 2 E 2 ground state corresponding to the metallic (a 1) 2 (e 2) 3 electron configuration. Full geometry optimizations lead to the prediction of their molecular structures for the lowest 2 E 2 and 1 A 1 states.
Hyperfine Interactions, 1986
A Mössbauer study of two mixed-valence FeIIFeI compounds C5H5Fe(C5H4)2 FeC6(CH3)6 (1) and ¦C6(CH3... more A Mössbauer study of two mixed-valence FeIIFeI compounds C5H5Fe(C5H4)2 FeC6(CH3)6 (1) and ¦C6(CH3)6 Fe(C5H4)2 Fe C6(CH3)6¦+ (2+) was carried out from 4.2K to room temperature. Zero-field spectra show two types of iron atoms for1 and one type for2+. Hence1 is a localized mixed-valence complex and2+ a delocalized mixed-valence complexe. High magnetic field spectra for 2+ give a negative sign for