Philippe Zinck | Université des Sciences et Technologies de Lille (Lille-1) (original) (raw)

Papers by Philippe Zinck

Research paper thumbnail of Isoprene-Styrene Chain Shuttling Copolymerization Mediated by a Lanthanide Half-Sandwich Complex and a Lanthanidocene: Straightforward Access to a New Type of Thermoplastic Elastomers

Angewandte Chemie International Edition, 2014

A lanthanide half-sandwich complex and a ansa lanthanidocene have been assessed for isoprene-styr... more A lanthanide half-sandwich complex and a ansa lanthanidocene have been assessed for isoprene-styrene chain shuttling copolymerization with n-butylethylmagnesium (BEM). In the presence of 1 equiv. BEM, a fully amorphous multiblock microstructure of soft and hard segments is achieved. The microstructure consists of poly(isoprene-co-styrene) blocks, with hard blocks rich in styrene and soft blocks rich in isoprene. The composition of the blocks and the resulting glass transition temperatures (T g ) can be easily modified by changing the feed and/or the relative amount of the catalysts, highlighting a new class of thermoplastic elastomers (TPEs) with tunable transition temperatures. The materials self-organize into nanostructures at the solid state.

Research paper thumbnail of Unexpected reactivities in chain shuttling copolymerizations

Polymer International, 2015

Research paper thumbnail of Tuning polyolefins and polydienes microstructure and architecture via coordinative chain transfer polymerization

Polymer International, 2012

Coordinative chain transfer polymerization (CCTP) is a reversible group transfer polymerization i... more Coordinative chain transfer polymerization (CCTP) is a reversible group transfer polymerization involving a transition metal catalyst and a main group metal alkyl. CCTP affords well controlled polymerizations of olefins and conjugated dienes with catalyst economy and good potentialities for polymer end-functionalization. New concepts have recently emerged in this field, affording unprecedented control over both microstructure and architecture of the resulting polymers and copolymers. These concepts are presented and discussed in this perspective.

Research paper thumbnail of Synthetic Strategies for Biomedical Polyesters Specialties

Research paper thumbnail of One-step synthesis of polyesters specialties for biomedical applications

Reviews in Environmental Science and Bio/Technology, 2009

Polyesters are widely used for biomedical applications such as drug delivery systems and resorbab... more Polyesters are widely used for biomedical applications such as drug delivery systems and resorbable implants. The degradation kinetic of these biopolymers can be tailored by the introduction of functional groups in their backbone, leading to a modification of their morphology and hydrophilicity. This is usually realized via long multistep reaction pathways. This contribution describes the emergence of one-step procedures for this purpose including enzymatic and Lewis acid catalyzed polycondensation as well as coordinative ring opening polymerization.

Research paper thumbnail of The Mechanism of Diene Polymerisation by Organolanthanide Catalysts Deduced from Microwave Experiments

Macromolecular Rapid Communications, 2005

The pseudoanionic character of the polymerisation of dienes by lanthanide catalysts has been asse... more The pseudoanionic character of the polymerisation of dienes by lanthanide catalysts has been assessed from microwave experiments. The microwave activation of isoprene polymerisation with Nd(BH 4 ) 3 (THF) 3 / Mg(Bu) 2 and Nd(BH 4 ) 3 (THF) 3 / Al(Et) 3 leads to a modification of the reactivity, the selectivity being only slightly modified. An explanation of the observed effect is proposed based on our current knowledge of the catalytic mechanism and by considering the alkylated complex as a ion pair. The bimetallic active species are thought to evolute toward a transition state where ion pairing is much more loose due to negative charge delocalisation, resulting in an enhancement in polarity during the reaction progress. The formation of a highly stabilising polymetallic specie involving tetraaluminate groups is advanced in order to explain the difference in reactivity observed between both catalytic systems. Finally, a "depolymerisation" effect of microwave irradiation in course of reaction is observed at high temperature.

Research paper thumbnail of Iconography : Organometallic catalysis: From concepts to selected applications

Data Revues 16310748 V13i3 S1631074810000135, Jan 4, 2010

Research paper thumbnail of Supporting info - Microstrcutreof polymyrcene by NMR

Research paper thumbnail of Polymyrcene microstructure revisited from precise high-field nuclear magnetic resonance analysis

Polymer, 2014

The microstructural analysis of 1,4-cis-and 1,4-trans-polymyrcene was conducted by means of thoro... more The microstructural analysis of 1,4-cis-and 1,4-trans-polymyrcene was conducted by means of thorough investigations at a very high field NMR (21.1T, 900 MHz). A set of 1D and 2D experiments helped to entirely assign the resonances of the spectra for both stereoisomers. A simple method to distinguish between each stereoisomer by NMR spectroscopy is finally provided.

Research paper thumbnail of Borohydrido Rare Earth Complexes as Precatalysts for the Polymerisation of Styrene

Zeitschrift für anorganische und allgemeine Chemie, 2006

Research paper thumbnail of Functionalization of syndiotactic polystyrene

Progress in Polymer Science, 2009

Syndiotactic polystyrene (sPS) is a promising material that has been commercialized and widely st... more Syndiotactic polystyrene (sPS) is a promising material that has been commercialized and widely studied by the academic community. Several drawbacks can however restrict its practical use: its brittleness, in areas where mechanical properties are important, the lack of polar groups, for adhesion and compatibility with other polymers, and the need to process sPS at high temperatures. These drawbacks can be overcome by the introduction of relevant functional groups into sPS. We present in this review the various strategies reported for the functionalization of syndiotactic polystyrene: statistical and sequential block copolymerization, chain transfer and chain end functionalization, polymerization of substituted styrenic monomers and chemical modification of sPS.

Research paper thumbnail of Nanoscale Blends between Immiscible Polymers via Simultaneous Non-Interfering Polymerisation

Macromolecular Chemistry and Physics, 2005

An important topic in polymer science seeks to improve the performances of polymer blends using n... more An important topic in polymer science seeks to improve the performances of polymer blends using nanoscale phase segregation. Here, blends between polystyrene and polycaprolactone are realised by a chemical route. The non-interfering character of the radical polymerisation of styrene and the lanthanide halide initiated ring-opening polymerisation of caprolactone is assessed. The molecular weights range from 2000 to 3500 for polycaprolactone and up to 140 000 for polystyrene, with reasonnable polydispersity indexes. From microcalorimetry measurements, it is shown that polystyrene and low molecular weight polycaprolactone are immiscible. The morphology of the blends between the two immiscible polymers studied by atomic force microscopy is consistent with nanometer-scale phase segregation.

Research paper thumbnail of On the hybrid character of glass fibres surface networks

Journal of Materials Science, 2005

The structure of organomineral coatings on glass fibres surface is a function of numerous paramet... more The structure of organomineral coatings on glass fibres surface is a function of numerous parameters. Among them, the molecular parameters of organosilane coupling agents in aqueous solution are of great importance . The understanding of hydrolysis and condensation mechanisms, the influence of the pH, temperature, concentration and the nature of the organic ligand are keys for the control of the structure . It is now well accepted that the structure resulting from the deposition from an aqueous solution of 1,4 γ -aminopropyltriethoxysilane consists in a threedimensional graded cross-linked network . The crosslinking density increases as the glass surface is reached and the outer layers are thought to be physisorbed. The situation still remains uncertain in the case of more complex industrial sizings, although it is assumed that the silane migrates to the interface providing an interfacial region which is similar to that obtained from the pure coupling agents solutions . The silane may act as a surfactant for the colloidal polymer particles in the sizing emulsion. The evolution of the structure in the course of a thermohydrolytic treatment has not been discussed so far, although changes in the mechanical behaviour of the fibres [8-10] and in the mechanical properties and the structure of interfacial zones in composites materials have been reported. The first steps of interfacial zones formation can be described by the dissolution of the outer physisorbed layers of the structure in the reacting comonomers, and the consecutive diffusion in the preformed inorganic-organic network . An attempt to apply general concepts from the chemistry of hybrid materials to the formation and properties of glass-fibers sizings and glass fibers-polymer interfaces can thus be proposed by considering the simultaneous reactions of organic and inorganic components. Apart from an analogy between the sizing treatment of glass fibers and the strengthening of silica glass by means of hybrid inorganic-organic coatings , the application of concepts from the chemistry of hybrid materials in the field of glass fibers sizings and their interfaces with a polymer has remained to our knowledge purely conceptual, suffering from a lack of experimental data. In fact, due to the geometry of these systems, the dimensions involved and the necessity to perform in situ measurements, the experimentation still remains difficult. In the early eighties, Miller [l4] developped a technique based on dynamical mechanical analysis which enables to characterize coatings directly on glass fibers strands.

Research paper thumbnail of Organometallic catalysis: From concepts to selected applications

Comptes Rendus Chimie, 2010

Dedicated to the memory of John Osborn, on the occasion of this meeting organized thanks to the o... more Dedicated to the memory of John Osborn, on the occasion of this meeting organized thanks to the organizing committee from Strasbourg University, where he spread his brilliant and clever knowledge of organometallic chemistry and catalysis.

Research paper thumbnail of Polymerization of ɛ-caprolactone using ruthenium(II) mixed metallocene catalysts and isopropyl alcohol: Living character and mechanistic study

J Mol Catal a Chem, 2011

A series of ruthenium(II) complexes with the general formula [Ru(η5-C5H5) (η6-substituted arene)]... more A series of ruthenium(II) complexes with the general formula [Ru(η5-C5H5) (η6-substituted arene)]+[PF6]− (substituted arene = 2-phenylpyridine (1), dibenzosuberone (2) and toluene (3)), in combination with isopropyl alcohol were used for the polymerization of ɛ-caprolactone. The polymerization was found to be quantitative and controlled, with PDI in the range 1.1–1.3. By means of MALDI-ToF analyses, functionalization studies with d,l-lactide and NMR monitoring techniques, it has been found that the polymerization proceeds via a living Activated Monomer mechanism (AM) involving an η6–η4 change of the coordination mode of the arene. These experimental results were corroborated by DFT studies. The growth of several polymer chains per ruthenium atom highlights interesting potentialities for molecular weight control and catalyst economy. The stability of the ruthenium complexes allows their recovery at the end of the polymerization, which can be viewed as a further advance in a green chemistry frame.Change in the coordination mode of the arene ligand upon ɛ-caprolactone interaction during an Activated Monomer mechanism promoted by ruthenium(II) mixed metallocenes.► First Ru(II) mixed metallocene catalysts for living Activated Monomer mechanism. ► Innovative polymerization mechanism based on arene η6–η4 slippage. ► DFT studies performed for the first time for a ROP via Activated Monomer mechanism. ► Recovery of the ruthenium catalytic complexes at the end of reaction. ► Growing of several polymer chains per metal: catalyst economy for green chemistry.

Research paper thumbnail of The “borohydride/alkyl route”: a new synthetic strategy in organolanthanides chemistry

Research paper thumbnail of hémilanthanidocènes en catalyse Ziegler-Natta: nouveaux catalyseurs, nouveaux matériaux

ABSTRACT Communication par affiche

Research paper thumbnail of Supporting Informations

Research paper thumbnail of Extrapolation techniques at short gauge lengths based on the weakest link concept for fibres exhibiting multiple failure modes

Philosophical Magazine A, 1999

In order to extrapolate the tensile strength of glass fibres at short gauge lengths corresponding... more In order to extrapolate the tensile strength of glass fibres at short gauge lengths corresponding for instance to the mean fragment length in a fragmentation test, four types of extrapolation techniques are reviewed. The ability of these models to describe the tensile strength of fibres is checked on E-glass fibres exhibiting multiple modes of failure. It is showed that Weibull unimodal statistics as well as bimodal CDF model lead to underestimated results. The double box approach provides values having a physical meaning but remain phenomenological. The need of a modeling taking into account a trimodality is emphasised.

Research paper thumbnail of Bis(phenolate)amine-supported lanthanide borohydride complexes for styrene and trans-1,4-isoprene (co-)polymerisations

Dalton Trans., 2015

New bis(phenolate)amine-supported neodymium borohydride complexes and their previously reported s... more New bis(phenolate)amine-supported neodymium borohydride complexes and their previously reported samarium analogues were tested as catalysts for the polymerisation of styrene and isoprene. Pr). X-ray structures of 1'-Nd and 2-Nd were determined and are presented. The neodymium borohydride complexes 1-Nd to 3-Nd and their samarium analogues Sm(O 2 N L )(BH 4 )(THF) (L = py (1-Sm), OMe (2-Sm), NMe 2 (3-Sm), Pr (4-Sm)) were tested as catalysts for the polymerisation of isoprene and styrene in the presence of nbutylethylmagnesium (Mg( n Bu)(Et)). All complexes were found to be active for the polymerisation of isoprene in these conditions, leading to polyisoprene up to 95.1% trans-1,4 stereoregular. They were also found to be active for the polymerisation of styrene leading to atactic polystyrene in all cases. Interestingly, samarium-based complexes were found to be more active than the neodymium ones toward this latter monomer, in sharp contrast to what is usually observed with rare earth borohydride complexes. The structure of both transpolyisoprenes and polystyrenes obtained were studied in detail by MALDI-ToF analysis in order to better understand the polymerisation mechanisms. The coordinative chain transfer polymerisation (CCTP) of both monomers was further conducted using Mg( n Bu)(Et) as transfer agent. Finally, the statistical copolymerisation of isoprene and styrene was examined using these catalytic systems, leading to the formation of poly[(trans-1,4-isoprene)-costyrene] with up to 39 % of styrene moieties inserted in a highly trans-1,4-stereoregular polyisoprene.

Research paper thumbnail of Isoprene-Styrene Chain Shuttling Copolymerization Mediated by a Lanthanide Half-Sandwich Complex and a Lanthanidocene: Straightforward Access to a New Type of Thermoplastic Elastomers

Angewandte Chemie International Edition, 2014

A lanthanide half-sandwich complex and a ansa lanthanidocene have been assessed for isoprene-styr... more A lanthanide half-sandwich complex and a ansa lanthanidocene have been assessed for isoprene-styrene chain shuttling copolymerization with n-butylethylmagnesium (BEM). In the presence of 1 equiv. BEM, a fully amorphous multiblock microstructure of soft and hard segments is achieved. The microstructure consists of poly(isoprene-co-styrene) blocks, with hard blocks rich in styrene and soft blocks rich in isoprene. The composition of the blocks and the resulting glass transition temperatures (T g ) can be easily modified by changing the feed and/or the relative amount of the catalysts, highlighting a new class of thermoplastic elastomers (TPEs) with tunable transition temperatures. The materials self-organize into nanostructures at the solid state.

Research paper thumbnail of Unexpected reactivities in chain shuttling copolymerizations

Polymer International, 2015

Research paper thumbnail of Tuning polyolefins and polydienes microstructure and architecture via coordinative chain transfer polymerization

Polymer International, 2012

Coordinative chain transfer polymerization (CCTP) is a reversible group transfer polymerization i... more Coordinative chain transfer polymerization (CCTP) is a reversible group transfer polymerization involving a transition metal catalyst and a main group metal alkyl. CCTP affords well controlled polymerizations of olefins and conjugated dienes with catalyst economy and good potentialities for polymer end-functionalization. New concepts have recently emerged in this field, affording unprecedented control over both microstructure and architecture of the resulting polymers and copolymers. These concepts are presented and discussed in this perspective.

Research paper thumbnail of Synthetic Strategies for Biomedical Polyesters Specialties

Research paper thumbnail of One-step synthesis of polyesters specialties for biomedical applications

Reviews in Environmental Science and Bio/Technology, 2009

Polyesters are widely used for biomedical applications such as drug delivery systems and resorbab... more Polyesters are widely used for biomedical applications such as drug delivery systems and resorbable implants. The degradation kinetic of these biopolymers can be tailored by the introduction of functional groups in their backbone, leading to a modification of their morphology and hydrophilicity. This is usually realized via long multistep reaction pathways. This contribution describes the emergence of one-step procedures for this purpose including enzymatic and Lewis acid catalyzed polycondensation as well as coordinative ring opening polymerization.

Research paper thumbnail of The Mechanism of Diene Polymerisation by Organolanthanide Catalysts Deduced from Microwave Experiments

Macromolecular Rapid Communications, 2005

The pseudoanionic character of the polymerisation of dienes by lanthanide catalysts has been asse... more The pseudoanionic character of the polymerisation of dienes by lanthanide catalysts has been assessed from microwave experiments. The microwave activation of isoprene polymerisation with Nd(BH 4 ) 3 (THF) 3 / Mg(Bu) 2 and Nd(BH 4 ) 3 (THF) 3 / Al(Et) 3 leads to a modification of the reactivity, the selectivity being only slightly modified. An explanation of the observed effect is proposed based on our current knowledge of the catalytic mechanism and by considering the alkylated complex as a ion pair. The bimetallic active species are thought to evolute toward a transition state where ion pairing is much more loose due to negative charge delocalisation, resulting in an enhancement in polarity during the reaction progress. The formation of a highly stabilising polymetallic specie involving tetraaluminate groups is advanced in order to explain the difference in reactivity observed between both catalytic systems. Finally, a "depolymerisation" effect of microwave irradiation in course of reaction is observed at high temperature.

Research paper thumbnail of Iconography : Organometallic catalysis: From concepts to selected applications

Data Revues 16310748 V13i3 S1631074810000135, Jan 4, 2010

Research paper thumbnail of Supporting info - Microstrcutreof polymyrcene by NMR

Research paper thumbnail of Polymyrcene microstructure revisited from precise high-field nuclear magnetic resonance analysis

Polymer, 2014

The microstructural analysis of 1,4-cis-and 1,4-trans-polymyrcene was conducted by means of thoro... more The microstructural analysis of 1,4-cis-and 1,4-trans-polymyrcene was conducted by means of thorough investigations at a very high field NMR (21.1T, 900 MHz). A set of 1D and 2D experiments helped to entirely assign the resonances of the spectra for both stereoisomers. A simple method to distinguish between each stereoisomer by NMR spectroscopy is finally provided.

Research paper thumbnail of Borohydrido Rare Earth Complexes as Precatalysts for the Polymerisation of Styrene

Zeitschrift für anorganische und allgemeine Chemie, 2006

Research paper thumbnail of Functionalization of syndiotactic polystyrene

Progress in Polymer Science, 2009

Syndiotactic polystyrene (sPS) is a promising material that has been commercialized and widely st... more Syndiotactic polystyrene (sPS) is a promising material that has been commercialized and widely studied by the academic community. Several drawbacks can however restrict its practical use: its brittleness, in areas where mechanical properties are important, the lack of polar groups, for adhesion and compatibility with other polymers, and the need to process sPS at high temperatures. These drawbacks can be overcome by the introduction of relevant functional groups into sPS. We present in this review the various strategies reported for the functionalization of syndiotactic polystyrene: statistical and sequential block copolymerization, chain transfer and chain end functionalization, polymerization of substituted styrenic monomers and chemical modification of sPS.

Research paper thumbnail of Nanoscale Blends between Immiscible Polymers via Simultaneous Non-Interfering Polymerisation

Macromolecular Chemistry and Physics, 2005

An important topic in polymer science seeks to improve the performances of polymer blends using n... more An important topic in polymer science seeks to improve the performances of polymer blends using nanoscale phase segregation. Here, blends between polystyrene and polycaprolactone are realised by a chemical route. The non-interfering character of the radical polymerisation of styrene and the lanthanide halide initiated ring-opening polymerisation of caprolactone is assessed. The molecular weights range from 2000 to 3500 for polycaprolactone and up to 140 000 for polystyrene, with reasonnable polydispersity indexes. From microcalorimetry measurements, it is shown that polystyrene and low molecular weight polycaprolactone are immiscible. The morphology of the blends between the two immiscible polymers studied by atomic force microscopy is consistent with nanometer-scale phase segregation.

Research paper thumbnail of On the hybrid character of glass fibres surface networks

Journal of Materials Science, 2005

The structure of organomineral coatings on glass fibres surface is a function of numerous paramet... more The structure of organomineral coatings on glass fibres surface is a function of numerous parameters. Among them, the molecular parameters of organosilane coupling agents in aqueous solution are of great importance . The understanding of hydrolysis and condensation mechanisms, the influence of the pH, temperature, concentration and the nature of the organic ligand are keys for the control of the structure . It is now well accepted that the structure resulting from the deposition from an aqueous solution of 1,4 γ -aminopropyltriethoxysilane consists in a threedimensional graded cross-linked network . The crosslinking density increases as the glass surface is reached and the outer layers are thought to be physisorbed. The situation still remains uncertain in the case of more complex industrial sizings, although it is assumed that the silane migrates to the interface providing an interfacial region which is similar to that obtained from the pure coupling agents solutions . The silane may act as a surfactant for the colloidal polymer particles in the sizing emulsion. The evolution of the structure in the course of a thermohydrolytic treatment has not been discussed so far, although changes in the mechanical behaviour of the fibres [8-10] and in the mechanical properties and the structure of interfacial zones in composites materials have been reported. The first steps of interfacial zones formation can be described by the dissolution of the outer physisorbed layers of the structure in the reacting comonomers, and the consecutive diffusion in the preformed inorganic-organic network . An attempt to apply general concepts from the chemistry of hybrid materials to the formation and properties of glass-fibers sizings and glass fibers-polymer interfaces can thus be proposed by considering the simultaneous reactions of organic and inorganic components. Apart from an analogy between the sizing treatment of glass fibers and the strengthening of silica glass by means of hybrid inorganic-organic coatings , the application of concepts from the chemistry of hybrid materials in the field of glass fibers sizings and their interfaces with a polymer has remained to our knowledge purely conceptual, suffering from a lack of experimental data. In fact, due to the geometry of these systems, the dimensions involved and the necessity to perform in situ measurements, the experimentation still remains difficult. In the early eighties, Miller [l4] developped a technique based on dynamical mechanical analysis which enables to characterize coatings directly on glass fibers strands.

Research paper thumbnail of Organometallic catalysis: From concepts to selected applications

Comptes Rendus Chimie, 2010

Dedicated to the memory of John Osborn, on the occasion of this meeting organized thanks to the o... more Dedicated to the memory of John Osborn, on the occasion of this meeting organized thanks to the organizing committee from Strasbourg University, where he spread his brilliant and clever knowledge of organometallic chemistry and catalysis.

Research paper thumbnail of Polymerization of ɛ-caprolactone using ruthenium(II) mixed metallocene catalysts and isopropyl alcohol: Living character and mechanistic study

J Mol Catal a Chem, 2011

A series of ruthenium(II) complexes with the general formula [Ru(η5-C5H5) (η6-substituted arene)]... more A series of ruthenium(II) complexes with the general formula [Ru(η5-C5H5) (η6-substituted arene)]+[PF6]− (substituted arene = 2-phenylpyridine (1), dibenzosuberone (2) and toluene (3)), in combination with isopropyl alcohol were used for the polymerization of ɛ-caprolactone. The polymerization was found to be quantitative and controlled, with PDI in the range 1.1–1.3. By means of MALDI-ToF analyses, functionalization studies with d,l-lactide and NMR monitoring techniques, it has been found that the polymerization proceeds via a living Activated Monomer mechanism (AM) involving an η6–η4 change of the coordination mode of the arene. These experimental results were corroborated by DFT studies. The growth of several polymer chains per ruthenium atom highlights interesting potentialities for molecular weight control and catalyst economy. The stability of the ruthenium complexes allows their recovery at the end of the polymerization, which can be viewed as a further advance in a green chemistry frame.Change in the coordination mode of the arene ligand upon ɛ-caprolactone interaction during an Activated Monomer mechanism promoted by ruthenium(II) mixed metallocenes.► First Ru(II) mixed metallocene catalysts for living Activated Monomer mechanism. ► Innovative polymerization mechanism based on arene η6–η4 slippage. ► DFT studies performed for the first time for a ROP via Activated Monomer mechanism. ► Recovery of the ruthenium catalytic complexes at the end of reaction. ► Growing of several polymer chains per metal: catalyst economy for green chemistry.

Research paper thumbnail of The “borohydride/alkyl route”: a new synthetic strategy in organolanthanides chemistry

Research paper thumbnail of hémilanthanidocènes en catalyse Ziegler-Natta: nouveaux catalyseurs, nouveaux matériaux

ABSTRACT Communication par affiche

Research paper thumbnail of Supporting Informations

Research paper thumbnail of Extrapolation techniques at short gauge lengths based on the weakest link concept for fibres exhibiting multiple failure modes

Philosophical Magazine A, 1999

In order to extrapolate the tensile strength of glass fibres at short gauge lengths corresponding... more In order to extrapolate the tensile strength of glass fibres at short gauge lengths corresponding for instance to the mean fragment length in a fragmentation test, four types of extrapolation techniques are reviewed. The ability of these models to describe the tensile strength of fibres is checked on E-glass fibres exhibiting multiple modes of failure. It is showed that Weibull unimodal statistics as well as bimodal CDF model lead to underestimated results. The double box approach provides values having a physical meaning but remain phenomenological. The need of a modeling taking into account a trimodality is emphasised.

Research paper thumbnail of Bis(phenolate)amine-supported lanthanide borohydride complexes for styrene and trans-1,4-isoprene (co-)polymerisations

Dalton Trans., 2015

New bis(phenolate)amine-supported neodymium borohydride complexes and their previously reported s... more New bis(phenolate)amine-supported neodymium borohydride complexes and their previously reported samarium analogues were tested as catalysts for the polymerisation of styrene and isoprene. Pr). X-ray structures of 1'-Nd and 2-Nd were determined and are presented. The neodymium borohydride complexes 1-Nd to 3-Nd and their samarium analogues Sm(O 2 N L )(BH 4 )(THF) (L = py (1-Sm), OMe (2-Sm), NMe 2 (3-Sm), Pr (4-Sm)) were tested as catalysts for the polymerisation of isoprene and styrene in the presence of nbutylethylmagnesium (Mg( n Bu)(Et)). All complexes were found to be active for the polymerisation of isoprene in these conditions, leading to polyisoprene up to 95.1% trans-1,4 stereoregular. They were also found to be active for the polymerisation of styrene leading to atactic polystyrene in all cases. Interestingly, samarium-based complexes were found to be more active than the neodymium ones toward this latter monomer, in sharp contrast to what is usually observed with rare earth borohydride complexes. The structure of both transpolyisoprenes and polystyrenes obtained were studied in detail by MALDI-ToF analysis in order to better understand the polymerisation mechanisms. The coordinative chain transfer polymerisation (CCTP) of both monomers was further conducted using Mg( n Bu)(Et) as transfer agent. Finally, the statistical copolymerisation of isoprene and styrene was examined using these catalytic systems, leading to the formation of poly[(trans-1,4-isoprene)-costyrene] with up to 39 % of styrene moieties inserted in a highly trans-1,4-stereoregular polyisoprene.