Valérie Maraval - Academia.edu (original) (raw)

Papers by Valérie Maraval

Research paper thumbnail of Difluorenyl carbo -Benzenes: Synthesis, Electronic Structure, and Two-Photon Absorption Properties of Hydrocarbon Quadrupolar Chromophores

Chemistry - A European Journal, 2015

The synthesis, crystal and electronic structures, and one-and two-photon absorption properties of... more The synthesis, crystal and electronic structures, and one-and two-photon absorption properties of two quadrupolar fluorenyl-substituted tetraphenyl carbo-benzenes are described. These all-hydrocarbon chromophores, differing in the nature of the linkers between the fluorenyl substituents and the carbo-benzene core (CÀC bonds for 3 a, CÀCCÀC expanders for 3 b), exhibit quasi-superimposable one-photon absorption (1PA) spectra but different twophoton absorption (2PA) cross-sections s 2PA . Z-scan measurements (under NIR femtosecond excitation) indeed showed that the CC expansion results in an approximately twofold increase in the s 2PA value, from 336 to 656 GM (1 GM = 10 À50 cm 4 s molecule À1 photon À1 ) at l = 800 nm. The first excited states of A u and A g symmetry accounting for 1PA and 2PA, respectively, were calculated at the TDDFT level of theory and used for sum-over-state estimations of s 2PA (l i ), in which l i = 2 hc/E i , h is Planck's constant, c is the speed of light, and E i is the energy of the 2PA-allowed transition. The calculated s 2PA values of 227 GM at 687 nm for 3 a and 349 GM at 708 nm for 3 b are in agreement with the Z-scan results. . It contains the synthetic principle of 5 b, photoluminescence spectra of 3 a and 3 b, the normalized transmittance curve of 3 b from Z-scan measurements, the near-frontier molecular orbitals of 3 a and 3 b, characteristics of the first singlet excited states of 3 a and 3 b (in vacuo and chloroform continuum), the contribution of intermediate 1PA-allowed states in the SOS expansion of the 2PA cross-section associated with the 4A g excited state of 3 a and 3 b, and copies of 1 H and 13 C NMR spectra, MS analyses, and voltammograms of 3 a and 3 b.

Research paper thumbnail of Carbomer of Benzene - A Tour de Force

Research paper thumbnail of Alkyne metathesis: toward simplicity and efficiency

Tetrahedron Letters, 2006

Alkyne Metathesis: Toward Simplicity and Efficiency. -The alkyne metathesis of representative hyd... more Alkyne Metathesis: Toward Simplicity and Efficiency. -The alkyne metathesis of representative hydrocarbon alkynes (I) is investigated. The formation of symmetrical alkynes (II) proceeds under mild conditions without catalyst-preactivation without an additive and without a suicide alkyne. DCE is shown to have a dramatic effect on the reaction. -(MARAVAL, V.; LEPETIT, C.; CAMINADE, A.-M.; MAJORAL, J.-P.; CHAUVIN*, R.; Tetrahedron Lett.

Research paper thumbnail of Surface, core, and structure modifications of phosphorus-containing dendrimers. Influence on the thermal stability

Tetrahedron, 2003

Three new series of phosphorus-containing dendrimers are described. Their solubility depends on t... more Three new series of phosphorus-containing dendrimers are described. Their solubility depends on the type of end groups they bear. Perfluoroalkyl chains give dendrimers soluble in chlorofluorocarbons, whereas guanidinium and pyridinium derivatives give watersoluble compounds. The thermal stability of these compounds, as well as of 19 other dendrimers of various generations, having various cores, or various end groups, or branching points is studied. The main feature of this study is that the internal structure of these dendrimers is thermally stable at least up to 3768C. The number of the generation has practically no influence, whereas the principal criterion influencing the thermal stability is the type of end groups. The water-soluble cationic dendrimers are the least stable, but even those are stable up to 2258C. For most of these dendrimers, an important percentage of mass (around 50%) is retained even at a temperature as high as 10008C. In the best case, up to 70% of the initial mass is retained at 10008C. q

Research paper thumbnail of 1,2,3,4-Heterohexatrienes as New Tools for Michael-Type Additions Usable for the Synthesis of Phosphorus Dendrimers

Synthesis, 2003

ABSTRACT 1,2,3,4-heterohexatrienes of type H2C=CHP(R)(2)=NP(R')(2)=X (X = 0, S) are used ... more ABSTRACT 1,2,3,4-heterohexatrienes of type H2C=CHP(R)(2)=NP(R')(2)=X (X = 0, S) are used in Michael-type additions of various primary or secondary amines and hydrazines. The use of functionalized amines allowed the grafting of other functions, such as a double or a triple bond, a sulfide, an imidazole, or a phenol, and various types of NH2 groups. These groups were used in condensation reactions, leading to the grafting of new functions such as phenols. Thus, the P(R)(2)=NP(R')(2)=X group appears as a new electron withdrawing group, very easily tunable by changing the R' or X substituents.

Research paper thumbnail of Variation of aromaticity by twisting or expanding the ring content

Pure and Applied Chemistry, 2000

In the following informations, the scheme, figure, and reference numbers correspond to those used... more In the following informations, the scheme, figure, and reference numbers correspond to those used in the corresponding article: Pure Appl. Chem., doi:10.1351/PAC-CON-09-11-07 © 2010 IUPAC. -1 sin[ 4(p+q)+2 ] }) m +. o(1/m)

Research paper thumbnail of Carbo -siloles, Part 2: Synthesis and Stereochemical Resolution of a Carbo -silolane Redox Equivalent

Phosphorus, Sulfur, and Silicon and the Related Elements, 2009

... Catherine Saccavini a , Christine Tedeschi a , Christine Lepetit a , Leila Yahi a , Caroline ... more ... Catherine Saccavini a , Christine Tedeschi a , Christine Lepetit a , Leila Yahi a , Caroline Pistre a , Valérie Maraval a & Remi Chauvin a pages 1573-1585. ... 7 12. Wong, W.-Y., Lee, AW-M., Wong, C.-K., Lu, G.-L., Zhang, H., Mo, T. and Lam, K.-T. 2002. New J. Chem. ...

Research paper thumbnail of Phosphorus-Containing Dendrimers: Synthesis and Properties

Phosphorus, Sulfur, and Silicon and the Related Elements, 2002

ABSTRACT Several series of phosphorus-containing dendrimers have been designed to study the varia... more ABSTRACT Several series of phosphorus-containing dendrimers have been designed to study the variation of their properties, depending on the type, the location (surface, branches, core, and cavities), and the number of functions implied.

Research paper thumbnail of Phosphorus-Containing Dendrimers and Their Transition Metal Complexes as Efficient Recoverable Multicenter Homogeneous Catalysts in Organic Synthesis

Organometallics, 2000

... Valérie Maraval, Régis Laurent, Anne-Marie ... complexes or one ruthenium diphosphine complex... more ... Valérie Maraval, Régis Laurent, Anne-Marie ... complexes or one ruthenium diphosphine complex located at the core have been found to be efficient, recoverable catalysts in three general organic reactions: Stille couplings, Knoevenagel condensations, and Michael additions. ...

Research paper thumbnail of Iminophosphine Palladium Complexes in Catalytic Stille Coupling Reactions:  From Monomers to Dendrimers

Organometallics, 2002

... Marek Koprowski, † Rosa-Maria Sebastián, ‡ Valérie Maraval, ‡ Maria Zablocka, †Victorio Cadie... more ... Marek Koprowski, † Rosa-Maria Sebastián, ‡ Valérie Maraval, ‡ Maria Zablocka, †Victorio Cadierno, ‡ Bruno Donnadieu, ‡ Alain Igau, ‡ Anne-Marie Caminade,* ‡ and Jean-Pierre Majoral* ‡. Centre of Molecular and Macromolecular ...

Research paper thumbnail of Carbo-mers: from skeleton to function

New Journal of Chemistry, 2007

ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Research paper thumbnail of Rapid Synthesis of Phosphorus-Containing Dendrimers with Controlled Molecular Architectures:  First Example of Surface-Block, Layer-Block, and Segment-Block Dendrimers Issued from the Same Dendron

Journal of the American Chemical Society, 2000

... Valérie Maraval, † Régis Laurent, † Bruno Donnadieu ... of several complex dendritic architec... more ... Valérie Maraval, † Régis Laurent, † Bruno Donnadieu ... of several complex dendritic architectures, obtained through core−core, core−surface, or core−core−surface−core couplings using very simple one-step reactions between these functions, such as Michael additions between ...

Research paper thumbnail of Accelerated methods of synthesis of phosphorus-containing dendrimers

Journal of Organometallic Chemistry, 2005

Research paper thumbnail of Decorating step-by-step and independently the surface and the core of dendrons

Journal of Organometallic Chemistry, 2007

Dendrons possessing one activated vinyl group at the core and several chlorine atoms at the end o... more Dendrons possessing one activated vinyl group at the core and several chlorine atoms at the end of the branches are used as starting materials to study the possibility to react independently the surface functions and the core function. In particular, the most powerful sequence of reactions for decorating them by organometallic complexes as end groups and amine or alcohol at the core has been determined. In the first step, phenol phosphines are grafted as end groups of the dendrons, and they can be used for the complexation of metals. However, these phosphines must be kept free when amines are used to react with the vinyl core in the next step. Depending on the type of phosphine end groups and on the type of function of the core (amine or alcohol), the complexation of ruthenium ([RuCl 2 (p-cymene)] 2 ) and rhodium ([RhCl(COD)] 2 ) derivatives by the phosphine end groups can occur without side reaction at the core.

Research paper thumbnail of Functionalized phosphorus derivatives of Salpen-like compounds: Synthesis and preliminary complexation studies

Journal of Organometallic Chemistry, 2006

A new class of Salpen analogues based on phosphorus derivatives where the classical alkylene back... more A new class of Salpen analogues based on phosphorus derivatives where the classical alkylene backbone has been replaced by a N-P-N linkage is described. Such linkage both affords a very good stability in water and an additional (fifth) potentially complexing site. The classical ortho-OH groups have been also replaced by various ortho-substituents, including diphenylphosphino groups. The synthesis of these compounds is easy and their structure can be varied at will at several levels. Several ways of synthesis can be used to combine the various fragments constituting these Salpen analogues. The structure of one of these fragments, an azide, was determined by X-ray crystallography. A preliminary study of the complexation ability of some of these new ligands was carried out with groups 10 (Ni) and 11 (Au) elements. Depending on the type of substituents and the type of metals used, these compounds can act as mono-, or tetra-dentate ligands.

Research paper thumbnail of Very large neutral and polyanionic Fe/Au cluster-containing dendrimers

Journal of Organometallic Chemistry, 2001

Treatment of tetrahydrofuran solutions of a series of ClAu-terminated dendrimers with the iron an... more Treatment of tetrahydrofuran solutions of a series of ClAu-terminated dendrimers with the iron anions [Fe 2 (CO) 7 (PPh 2 )] − and [Fe 3 (CO) 11 ] 2 − has allowed the new dendrimer species decorated on the surface by Fe 2 Au or Fe 3 Au units to be isolated, including one having up to 192 Fe 2 Au clusters.

Research paper thumbnail of “Lego” Chemistry for the Straightforward Synthesis of Dendrimers

The Journal of Organic Chemistry, 2003

A new straightforward method of synthesis of dendrimers, using two branched monomers (CA 2 and DB... more A new straightforward method of synthesis of dendrimers, using two branched monomers (CA 2 and DB 2 ), is described. Each generation is obtained in a single quantitative step, with only N 2 or H 2 O as byproducts; generation 4 is obtained in only four steps. The end groups are alternatively phosphines and hydrazines; their versatile reactivity is illustrated by the reaction of generation 4 with a branched CD 5 monomer, which increases the number of end groups in a single step from 48 to 250.

Research paper thumbnail of Manganese(III) Porphyrin Catalysts for the Oxidation of Terpene Derivatives: A Comparative Study

Journal of Catalysis, 2002

... Permissions & Reprints. Regular Article. Manganese(III) Porphyrin Catalysts for the Oxida... more ... Permissions & Reprints. Regular Article. Manganese(III) Porphyrin Catalysts for the Oxidation of Terpene Derivatives: A Comparative Study. Valérie Maraval a , Jean-Erick Ancel b and Bernard Meunier a , 1. ... 26J.V. Crivello and R. Narayan, Macromolecules 29 (1996), p. 433. ...

Research paper thumbnail of The Intricate Assembling of gem -Diphenylpropargylic Units

European Journal of Organic Chemistry, 2008

ABSTRACT While optimized procedures for selective propargylic – versus allenic – attack (in parti... more ABSTRACT While optimized procedures for selective propargylic – versus allenic – attack (in particular by alkynylsilanes) have proven to be compatible with many substitution patterns at the propargylic center, the case of diarylpropargyl electrophiles has remained problematic. The intrinsic reactivity of 1,1-diphenylpropargylic alcohols [R–C≡C–C(Ph2)OH (R = TMS, H, Me)] in the presence of various acids (and in the absence of additional nucleophile) has thus been systematically investigated. Whereas the monophenyl analogues [R–C≡C–CH(Ph)OH] afford the expected bis(phenylpropargyl) ethers, the diphenyl versions undergo complex but quite selective processes to afford various structural types: depending on the acid used, a diallene, an allenyne, an indenylallene, an indanone or a condensed tetra- and pentacycles were obtained. When the reactions were conducted in the presence of an alkynylsilane capable of playing the role of a competing nucleophile, the expected propargylic substitution products – dialkynyldiphenylmethanes or their isomers – were never observed. The hitherto unknown simple hydrocarbons diethynyl- and dipropynyl-diphenylmethane could, however, be obtained in low yields through a four-step sequence involving allenylidene- and alkynylruthenium intermediates.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Research paper thumbnail of Michael-Type Addition of Amines to the Vinyl Core of Dendrons − Application to the Synthesis of Multidendritic Systems

European Journal of Organic Chemistry, 2000

Research paper thumbnail of Difluorenyl carbo -Benzenes: Synthesis, Electronic Structure, and Two-Photon Absorption Properties of Hydrocarbon Quadrupolar Chromophores

Chemistry - A European Journal, 2015

The synthesis, crystal and electronic structures, and one-and two-photon absorption properties of... more The synthesis, crystal and electronic structures, and one-and two-photon absorption properties of two quadrupolar fluorenyl-substituted tetraphenyl carbo-benzenes are described. These all-hydrocarbon chromophores, differing in the nature of the linkers between the fluorenyl substituents and the carbo-benzene core (CÀC bonds for 3 a, CÀCCÀC expanders for 3 b), exhibit quasi-superimposable one-photon absorption (1PA) spectra but different twophoton absorption (2PA) cross-sections s 2PA . Z-scan measurements (under NIR femtosecond excitation) indeed showed that the CC expansion results in an approximately twofold increase in the s 2PA value, from 336 to 656 GM (1 GM = 10 À50 cm 4 s molecule À1 photon À1 ) at l = 800 nm. The first excited states of A u and A g symmetry accounting for 1PA and 2PA, respectively, were calculated at the TDDFT level of theory and used for sum-over-state estimations of s 2PA (l i ), in which l i = 2 hc/E i , h is Planck's constant, c is the speed of light, and E i is the energy of the 2PA-allowed transition. The calculated s 2PA values of 227 GM at 687 nm for 3 a and 349 GM at 708 nm for 3 b are in agreement with the Z-scan results. . It contains the synthetic principle of 5 b, photoluminescence spectra of 3 a and 3 b, the normalized transmittance curve of 3 b from Z-scan measurements, the near-frontier molecular orbitals of 3 a and 3 b, characteristics of the first singlet excited states of 3 a and 3 b (in vacuo and chloroform continuum), the contribution of intermediate 1PA-allowed states in the SOS expansion of the 2PA cross-section associated with the 4A g excited state of 3 a and 3 b, and copies of 1 H and 13 C NMR spectra, MS analyses, and voltammograms of 3 a and 3 b.

Research paper thumbnail of Carbomer of Benzene - A Tour de Force

Research paper thumbnail of Alkyne metathesis: toward simplicity and efficiency

Tetrahedron Letters, 2006

Alkyne Metathesis: Toward Simplicity and Efficiency. -The alkyne metathesis of representative hyd... more Alkyne Metathesis: Toward Simplicity and Efficiency. -The alkyne metathesis of representative hydrocarbon alkynes (I) is investigated. The formation of symmetrical alkynes (II) proceeds under mild conditions without catalyst-preactivation without an additive and without a suicide alkyne. DCE is shown to have a dramatic effect on the reaction. -(MARAVAL, V.; LEPETIT, C.; CAMINADE, A.-M.; MAJORAL, J.-P.; CHAUVIN*, R.; Tetrahedron Lett.

Research paper thumbnail of Surface, core, and structure modifications of phosphorus-containing dendrimers. Influence on the thermal stability

Tetrahedron, 2003

Three new series of phosphorus-containing dendrimers are described. Their solubility depends on t... more Three new series of phosphorus-containing dendrimers are described. Their solubility depends on the type of end groups they bear. Perfluoroalkyl chains give dendrimers soluble in chlorofluorocarbons, whereas guanidinium and pyridinium derivatives give watersoluble compounds. The thermal stability of these compounds, as well as of 19 other dendrimers of various generations, having various cores, or various end groups, or branching points is studied. The main feature of this study is that the internal structure of these dendrimers is thermally stable at least up to 3768C. The number of the generation has practically no influence, whereas the principal criterion influencing the thermal stability is the type of end groups. The water-soluble cationic dendrimers are the least stable, but even those are stable up to 2258C. For most of these dendrimers, an important percentage of mass (around 50%) is retained even at a temperature as high as 10008C. In the best case, up to 70% of the initial mass is retained at 10008C. q

Research paper thumbnail of 1,2,3,4-Heterohexatrienes as New Tools for Michael-Type Additions Usable for the Synthesis of Phosphorus Dendrimers

Synthesis, 2003

ABSTRACT 1,2,3,4-heterohexatrienes of type H2C=CHP(R)(2)=NP(R')(2)=X (X = 0, S) are used ... more ABSTRACT 1,2,3,4-heterohexatrienes of type H2C=CHP(R)(2)=NP(R')(2)=X (X = 0, S) are used in Michael-type additions of various primary or secondary amines and hydrazines. The use of functionalized amines allowed the grafting of other functions, such as a double or a triple bond, a sulfide, an imidazole, or a phenol, and various types of NH2 groups. These groups were used in condensation reactions, leading to the grafting of new functions such as phenols. Thus, the P(R)(2)=NP(R')(2)=X group appears as a new electron withdrawing group, very easily tunable by changing the R' or X substituents.

Research paper thumbnail of Variation of aromaticity by twisting or expanding the ring content

Pure and Applied Chemistry, 2000

In the following informations, the scheme, figure, and reference numbers correspond to those used... more In the following informations, the scheme, figure, and reference numbers correspond to those used in the corresponding article: Pure Appl. Chem., doi:10.1351/PAC-CON-09-11-07 © 2010 IUPAC. -1 sin[ 4(p+q)+2 ] }) m +. o(1/m)

Research paper thumbnail of Carbo -siloles, Part 2: Synthesis and Stereochemical Resolution of a Carbo -silolane Redox Equivalent

Phosphorus, Sulfur, and Silicon and the Related Elements, 2009

... Catherine Saccavini a , Christine Tedeschi a , Christine Lepetit a , Leila Yahi a , Caroline ... more ... Catherine Saccavini a , Christine Tedeschi a , Christine Lepetit a , Leila Yahi a , Caroline Pistre a , Valérie Maraval a & Remi Chauvin a pages 1573-1585. ... 7 12. Wong, W.-Y., Lee, AW-M., Wong, C.-K., Lu, G.-L., Zhang, H., Mo, T. and Lam, K.-T. 2002. New J. Chem. ...

Research paper thumbnail of Phosphorus-Containing Dendrimers: Synthesis and Properties

Phosphorus, Sulfur, and Silicon and the Related Elements, 2002

ABSTRACT Several series of phosphorus-containing dendrimers have been designed to study the varia... more ABSTRACT Several series of phosphorus-containing dendrimers have been designed to study the variation of their properties, depending on the type, the location (surface, branches, core, and cavities), and the number of functions implied.

Research paper thumbnail of Phosphorus-Containing Dendrimers and Their Transition Metal Complexes as Efficient Recoverable Multicenter Homogeneous Catalysts in Organic Synthesis

Organometallics, 2000

... Valérie Maraval, Régis Laurent, Anne-Marie ... complexes or one ruthenium diphosphine complex... more ... Valérie Maraval, Régis Laurent, Anne-Marie ... complexes or one ruthenium diphosphine complex located at the core have been found to be efficient, recoverable catalysts in three general organic reactions: Stille couplings, Knoevenagel condensations, and Michael additions. ...

Research paper thumbnail of Iminophosphine Palladium Complexes in Catalytic Stille Coupling Reactions:  From Monomers to Dendrimers

Organometallics, 2002

... Marek Koprowski, † Rosa-Maria Sebastián, ‡ Valérie Maraval, ‡ Maria Zablocka, †Victorio Cadie... more ... Marek Koprowski, † Rosa-Maria Sebastián, ‡ Valérie Maraval, ‡ Maria Zablocka, †Victorio Cadierno, ‡ Bruno Donnadieu, ‡ Alain Igau, ‡ Anne-Marie Caminade,* ‡ and Jean-Pierre Majoral* ‡. Centre of Molecular and Macromolecular ...

Research paper thumbnail of Carbo-mers: from skeleton to function

New Journal of Chemistry, 2007

ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Research paper thumbnail of Rapid Synthesis of Phosphorus-Containing Dendrimers with Controlled Molecular Architectures:  First Example of Surface-Block, Layer-Block, and Segment-Block Dendrimers Issued from the Same Dendron

Journal of the American Chemical Society, 2000

... Valérie Maraval, † Régis Laurent, † Bruno Donnadieu ... of several complex dendritic architec... more ... Valérie Maraval, † Régis Laurent, † Bruno Donnadieu ... of several complex dendritic architectures, obtained through core−core, core−surface, or core−core−surface−core couplings using very simple one-step reactions between these functions, such as Michael additions between ...

Research paper thumbnail of Accelerated methods of synthesis of phosphorus-containing dendrimers

Journal of Organometallic Chemistry, 2005

Research paper thumbnail of Decorating step-by-step and independently the surface and the core of dendrons

Journal of Organometallic Chemistry, 2007

Dendrons possessing one activated vinyl group at the core and several chlorine atoms at the end o... more Dendrons possessing one activated vinyl group at the core and several chlorine atoms at the end of the branches are used as starting materials to study the possibility to react independently the surface functions and the core function. In particular, the most powerful sequence of reactions for decorating them by organometallic complexes as end groups and amine or alcohol at the core has been determined. In the first step, phenol phosphines are grafted as end groups of the dendrons, and they can be used for the complexation of metals. However, these phosphines must be kept free when amines are used to react with the vinyl core in the next step. Depending on the type of phosphine end groups and on the type of function of the core (amine or alcohol), the complexation of ruthenium ([RuCl 2 (p-cymene)] 2 ) and rhodium ([RhCl(COD)] 2 ) derivatives by the phosphine end groups can occur without side reaction at the core.

Research paper thumbnail of Functionalized phosphorus derivatives of Salpen-like compounds: Synthesis and preliminary complexation studies

Journal of Organometallic Chemistry, 2006

A new class of Salpen analogues based on phosphorus derivatives where the classical alkylene back... more A new class of Salpen analogues based on phosphorus derivatives where the classical alkylene backbone has been replaced by a N-P-N linkage is described. Such linkage both affords a very good stability in water and an additional (fifth) potentially complexing site. The classical ortho-OH groups have been also replaced by various ortho-substituents, including diphenylphosphino groups. The synthesis of these compounds is easy and their structure can be varied at will at several levels. Several ways of synthesis can be used to combine the various fragments constituting these Salpen analogues. The structure of one of these fragments, an azide, was determined by X-ray crystallography. A preliminary study of the complexation ability of some of these new ligands was carried out with groups 10 (Ni) and 11 (Au) elements. Depending on the type of substituents and the type of metals used, these compounds can act as mono-, or tetra-dentate ligands.

Research paper thumbnail of Very large neutral and polyanionic Fe/Au cluster-containing dendrimers

Journal of Organometallic Chemistry, 2001

Treatment of tetrahydrofuran solutions of a series of ClAu-terminated dendrimers with the iron an... more Treatment of tetrahydrofuran solutions of a series of ClAu-terminated dendrimers with the iron anions [Fe 2 (CO) 7 (PPh 2 )] − and [Fe 3 (CO) 11 ] 2 − has allowed the new dendrimer species decorated on the surface by Fe 2 Au or Fe 3 Au units to be isolated, including one having up to 192 Fe 2 Au clusters.

Research paper thumbnail of “Lego” Chemistry for the Straightforward Synthesis of Dendrimers

The Journal of Organic Chemistry, 2003

A new straightforward method of synthesis of dendrimers, using two branched monomers (CA 2 and DB... more A new straightforward method of synthesis of dendrimers, using two branched monomers (CA 2 and DB 2 ), is described. Each generation is obtained in a single quantitative step, with only N 2 or H 2 O as byproducts; generation 4 is obtained in only four steps. The end groups are alternatively phosphines and hydrazines; their versatile reactivity is illustrated by the reaction of generation 4 with a branched CD 5 monomer, which increases the number of end groups in a single step from 48 to 250.

Research paper thumbnail of Manganese(III) Porphyrin Catalysts for the Oxidation of Terpene Derivatives: A Comparative Study

Journal of Catalysis, 2002

... Permissions & Reprints. Regular Article. Manganese(III) Porphyrin Catalysts for the Oxida... more ... Permissions & Reprints. Regular Article. Manganese(III) Porphyrin Catalysts for the Oxidation of Terpene Derivatives: A Comparative Study. Valérie Maraval a , Jean-Erick Ancel b and Bernard Meunier a , 1. ... 26J.V. Crivello and R. Narayan, Macromolecules 29 (1996), p. 433. ...

Research paper thumbnail of The Intricate Assembling of gem -Diphenylpropargylic Units

European Journal of Organic Chemistry, 2008

ABSTRACT While optimized procedures for selective propargylic – versus allenic – attack (in parti... more ABSTRACT While optimized procedures for selective propargylic – versus allenic – attack (in particular by alkynylsilanes) have proven to be compatible with many substitution patterns at the propargylic center, the case of diarylpropargyl electrophiles has remained problematic. The intrinsic reactivity of 1,1-diphenylpropargylic alcohols [R–C≡C–C(Ph2)OH (R = TMS, H, Me)] in the presence of various acids (and in the absence of additional nucleophile) has thus been systematically investigated. Whereas the monophenyl analogues [R–C≡C–CH(Ph)OH] afford the expected bis(phenylpropargyl) ethers, the diphenyl versions undergo complex but quite selective processes to afford various structural types: depending on the acid used, a diallene, an allenyne, an indenylallene, an indanone or a condensed tetra- and pentacycles were obtained. When the reactions were conducted in the presence of an alkynylsilane capable of playing the role of a competing nucleophile, the expected propargylic substitution products – dialkynyldiphenylmethanes or their isomers – were never observed. The hitherto unknown simple hydrocarbons diethynyl- and dipropynyl-diphenylmethane could, however, be obtained in low yields through a four-step sequence involving allenylidene- and alkynylruthenium intermediates.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Research paper thumbnail of Michael-Type Addition of Amines to the Vinyl Core of Dendrons − Application to the Synthesis of Multidendritic Systems

European Journal of Organic Chemistry, 2000