Papers by Jean-franÇois Carpentier
Several families of heteroleptic tetrelenes of general formulae M(E^R(NMe2))[N(SiMe3)2] and M(O^E... more Several families of heteroleptic tetrelenes of general formulae M(E^R(NMe2))[N(SiMe3)2] and M(O^E^R(NMe2))[N(SiMe3)2] (where E = S, Se; M = Ge, Sn, Pb; R(NMe2) = 2-(Me2NCH2)C6H4] supported by organochalcogenolato ligands have been prepared and fully characterised. The coordination chemistry of these ligands containing both hard (N, O) and soft (S, Se) atoms onto metals of varying size, polarisability, electropositivity and electrostatic surface potential has been explored. In the molecular solid-state, the complexes M(E^R(NMe2))[N(SiMe3)2] are monomeric, although an occurrence of weak PbSe intermolecular interactions yielding a bimolecular species has been identified in the case of the plumbylene Pb[SeC6H4(CH2NMe2)-2][N(SiMe3)2]. On the other hand, all complexes M(O^E^R(NMe2))[N(SiMe3)2] form centro-symmetric bimetallic dimers with O-bridging atoms. Multinuclear ((29)Si, (77)Se, (119)Sn, (207)Pb) NMR spectroscopy and crystallographic studies reveal that the metal preferably remains 3-coordinated in all these heteroleptic complexes with absence of coordination of N and S/Se atoms, unless severe depletion of electronic density onto the metal is enforced. Coordination of these heteroelements can thus be achieved either through replacement of α-CH3 substituents (as in the ligand 2-(Me2NCH2)C6H4SeCH2C(Me)2O(-)) by electron-withdrawing α-CF3 moieties (as in the ligand 2-(Me2NCH2)C6H4SeCH2C(CF3)2O(-)), or else with recourse to the use of a cationizing agent leading to the formation of the ion pair [{2-(Me2NCH2)C6H4SeCH2C(Me)2O}Pb](+)·[H2N{B(C6F5)3}2](-) where the cationic metal complex is associated to a weakly-coordinating anion. The data collated herein provide compelling evidence that the coordination chemistry of divalent tetrel elements with ligands featuring both hard and soft donors cannot be reliably anticipated by sole use of general concepts such as the HSAB theory. The related metal complexes containing the rigid 8-(NMe2)naphthalen-1-yl group are also discussed.
Macromolecular Rapid Communications
Coordination Chemistry Reviews
Over the past five years, Ga(III) and most notably In(III) precursors have attracted a growing in... more Over the past five years, Ga(III) and most notably In(III) precursors have attracted a growing interest for application in ROP catalysis of cyclic esters, primarily lactide, and may now be considered as potentially efficient ROP initiators of cyclic esters/carbonates. Despite their higher cost (vs. Al), Ga and In derivatives exhibit key attractive features including: (i) Ga(III) and In(III) are biocompatible metal centers and (ii) their precursors are typically more stable than organoaluminum species in polar media. The present contribution reviews discrete Ga(III) and In(III) compounds thus far developed as ROP initiators of cyclic esters/carbonates. The very few reports on Ga(III)-mediated ROPs of cyclic ethers are also included. In addition to the ROP performances of such species, the synthesis and structural characterization of these initiators are also provided and thoroughly discussed with, whenever appropriate, the establishment of structure/reactivity relationships and mecha...
IEEE Ultrasonics Symposium, 2005., 2005
This paper demonstrates the feasibility of an above- IC bulk acoustic wave technology for wireles... more This paper demonstrates the feasibility of an above- IC bulk acoustic wave technology for wireless applications in the 2 to 6 GHz frequency range. BAW filters with balanced input and output have been integrated as a post-process directly above BiCMOS wafers comprising RF circuits. A double-lattice filter designed for 2.14 GHz W-CDMA and featuring insertion loss of - 3dB and
Tetrahedron: Asymmetry, 1998
The hydrogenation of ethyl 2,4-dioxovalerate in the presence of chiral rhodium or ruthenium catal... more The hydrogenation of ethyl 2,4-dioxovalerate in the presence of chiral rhodium or ruthenium catalysts provides direct access to 2-hydroxy-4-methyltetrahydrofuran-2-one 4 with syn:anti ratios of up to 84:16 and with up to 98% and 94% e.e. in the syn and anti form, respectively.
Coordination Chemistry Reviews, 2004
Tetrahedron Letters, 1996
The trimethoxy-o-aroyldiphenylphosphorylmethylbenzamide 9 can be cyclized by treatment with KHMDS... more The trimethoxy-o-aroyldiphenylphosphorylmethylbenzamide 9 can be cyclized by treatment with KHMDS; the procedure has been employed to synthesize (±)Cherylline 1 and its dimethylether 2.
ChemInform, 1996
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 100 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.
Macromolecules, 2015
ABSTRACT The sequential and random ring-opening polymerizations (ROP) of racemic-trans-cyclohexen... more ABSTRACT The sequential and random ring-opening polymerizations (ROP) of racemic-trans-cyclohexene carbonate (rac-CHC) or enantiopure trans-(R,R)-cyclohexene carbonate ((R,R)-CHC) with l-lactide (LLA) or trimethylene carbonate (TMC) have been performed. Catalytic systems based on zinc diaminophenolate [(NNO)ZnEt] ((NNO)− = 2,4-di-tert-butyl-6-{[(2′-dimethylaminoethyl)methylamino]methyl}phenolate)) or tris[N,N-bis(trimethysilyl)amide]yttrium (Y[N(SiMe3)2]3) complexes, or a guanidine-type organocatalyst (1,5,7-triazabicyclo[4.4.0]dec-5-ene, TBD), combined to an alcohol (BnOH or iPrOH) as initiator/chain-transfer agent were used. Well-defined diblock P(rac-CHC)-b-PLLA and P((R,R)-CHC)-b-PLLA and random P(rac-CHC)-co-PLLA and P(rac-CHC)-co-PTMC copolymers were thus synthesized with molar mass values up to Mn,NMR = ca. 34 000 g mol-1 and rather narrow dispersity values (ĐM = 1.2-1.7). 1H and 13C{1H} NMR characterizations of the copolymers revealed the presence of −OBn or −OiPr chain-end groups, thereby supporting the active role of exogenous alcohol as initiator. No decarboxylation reaction was ever observed during any copolymerization, thus providing PCHC/PLLA and PCHC/PTMC copolymers void of ether defects. Thermal analysis of the copolymers assessed by DSC and TGA confirmed their block or random structure. The block PCHC-b-PLA and the random PCHC-co-PLLA and PCHC-co-PTMC copolymers represent the first examples of such copolymers synthesized by ring-opening copolymerization of the two comonomers. The latter PCHC-co-PTMC copolymers randomly combining CHC and TMC units are the first examples ever reported.
Tetrahedron: Asymmetry, 1997
The enantioselective hydrogenation of several 0t-keto esters (3a-f, 5a-j), ctketo amides (7a--e) ... more The enantioselective hydrogenation of several 0t-keto esters (3a-f, 5a-j), ctketo amides (7a--e) and isatine derivatives (ga--d) with a set of four representative neutral homogeneous rhodium-amidophosphine-phosphinite catalysts has been investigated. Trifluoroacetato-Rh-AMPP catalytic precursors promoted the rapid, efficient synthesis of aliphatic ct-hydroxy esters 4a-f in moderate to high enantioselectivities (66--95% ee), in contrast to most aromatic 0t-hydroxy esters 6a-j (8-81% ee). Best enantioselectivities for et-hydroxy amides 8a--e (85-95% ee) and dioxindoles load (80-94% ee) were obtained with chloro-Rh-AMPP precursors. It is proposed that, contrary to ot-keto amides, otketo esters do not chelate onto the rhodium center and that, in such circumstances, the asymmetric induction is mainly controlled by the steric hindrance around the C=O function. ~) 1997
Coordination Chemistry Reviews, 1998
... 2. AMP, AMPP and BAMP ligands. Amino(do)phosphine-phosphinite ligands exhibit a dissymmetric ... more ... 2. AMP, AMPP and BAMP ligands. Amino(do)phosphine-phosphinite ligands exhibit a dissymmetric functionality due to the presence of phosphorus moieties at both the nitrogen and oxygen atoms. ... 2.2. Preparation of AMP, AMPP and BAMP ligands. ...
Chemical reviews, Jan 21, 2015
Angewandte Chemie (International ed. in English), Jan 7, 2015
The reactivity towards AlMe3 of discrete cationic ansa-zirconocenes 2 a,b that are ubiquitously u... more The reactivity towards AlMe3 of discrete cationic ansa-zirconocenes 2 a,b that are ubiquitously used in isoselective propylene polymerization and based on [{Ph(H)C(3,6-tBu2 -Flu)(3-tBu-5-Et-Cp)}ZrMe2 )] {Cp-Flu} and rac-[{Me2 Si-(2-Me-4-Ph-Ind)2 }ZrMe2 ] {SBI} was scrutinized. The first example of a structurally characterized Group 4 metallocene AlMe3 adduct (3 b) is reported. In the presence of excess AlMe3 , the {SBI}-based AlMe3 adduct 3 b undergoes a slow decomposition via CH activation in a bridging methyl unit to yield a new species (4 b) with a trimetallic {Zr(μ-CH2 )(μ-Me)AlMe(μ-Me)AlMe2 } core. EXSY NMR data for the process 2 b⇄3 b→4 b suggest very rapid and reversible binding of an additional AlMe3 molecule onto AlMe3 adduct 3 b. The resulting heterotrimetallic species intermediates exchange of methyl groups between different metal centers and slowly undergoes the CH activation reaction towards 4 b.
PowerCon 2000. 2000 International Conference on Power System Technology. Proceedings (Cat. No.00EX409), 2000
In conventional secure economic dispatch and, more generally, in conventional active optimal powe... more In conventional secure economic dispatch and, more generally, in conventional active optimal power flows, power system security after contingency is taken into account through additional constraints. This is not completely satisfactory from an economic point of view. In this paper, first the problem statement is improved so as to become economically satisfactory, by introducing possible corrective load curtailments after contingency
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 13, 2015
Stable heteroleptic amido Yb(II) and Sm(II) complexes bearing aminoether-phenolate ligands and de... more Stable heteroleptic amido Yb(II) and Sm(II) complexes bearing aminoether-phenolate ligands and devoid of coordinated solvent have been structurally characterized. They afford highly active, chemoselective and, in the case of monoadditions, 100 % anti-Markovnikov regiospecific catalysts (down to 0.04 mol % loading) for the hydrophosphination of styrene with PhPH2 under mild conditions.
Tetrahedron: Asymmetry, 1998
Chemoselective transfer hydrogenation of β-ketoesters to the corresponding alcohols is achieved i... more Chemoselective transfer hydrogenation of β-ketoesters to the corresponding alcohols is achieved in the presence of catalytic combinations of [RuCl 2 (η 6 -arene)] 2 and ephedrine or diamino type chiral ligands with activities up to 190 h −1 at 20°C and moderate to good enantiomeric excesses ranging from 36 to 94%.
Dalton Trans., 2014
Scandium and yttrium amide complexes Ln{ONXO(R1,R2)}(N(SiHMe2)2)(THF)n (Ln = Sc, n = 0 or Y, n = ... more Scandium and yttrium amide complexes Ln{ONXO(R1,R2)}(N(SiHMe2)2)(THF)n (Ln = Sc, n = 0 or Y, n = 1; X = NMe2 or OMe; R(1) = Cumyl or p-Cl-Cumyl; R(2) = Me or Cumyl) were prepared by aminolysis of Ln[N(SiHMe2)2]3(THF) with the corresponding tetradentate diamino- or alkoxy-amino-bis(phenol) pro-ligands {ONXO(R1,R2)}H2. In the solid state and in toluene solution, the scandium complexes are monomeric and 5-coordinated, while the analogous yttrium complexes all bear an extra THF-coordinated molecule and are 6-coordinated. Sc{ONXO(R1,R2)}(N(SiHMe2)2) complexes are single-site initiators for the ring-opening polymerization (ROP) of racemic lactide but are less active than their yttrium analogues Y{ONXO(R1,R2)}(N(SiHMe2)2)(THF); also, in contrast to the latter ones, they are inactive in the ROP of the more demanding racemic β-butyrolactone. On the other hand, the scandium amide complexes feature a significantly improved control over the ROP of lactide, yielding PLAs with much narrower molecular weight distributions (Đ(M) < 1.1 for Sc vs. 1.5-2.0 for Y). The yttrium complex with the very bulky o,p-dicumyl-substituted ligand is more heteroselective than its scandium analogue (P(r) = 0.88 vs. 0.83), while the opposite is observed with complexes based on p-methyl-substituted ligands (P(r) = 0.50 in toluene or 0.72-0.75 in THF for Y vs. P(r) = 0.75-0.83 for Sc in toluene). These reactivity and selectivity trends are rationalized by a much more sterically crowded coordination sphere in scandium than in yttrium complexes.
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Papers by Jean-franÇois Carpentier