Export 18 results:
Sort by: Author [ Title  (Desc)] Type Year
A B C D E [F] G H I J K L M N O P Q R S T U V W X Y Z   [Show ALL]
de Fremont, Pierre, Herve Clavier, Vitor Rosa, Teresa Aviles, and Pierre Braunstein. "{Synthesis, Characterization, and Reactivity of Cationic Gold(I) alpha-Diimine Complexes}." {ORGANOMETALLICS}. {30} (2011): {2241-2251}. Abstract

{{A series of cationic gold(I) alpha-diimine complexes of the type {[}(NHC)Au(alpha-diimine)]X or {[}(PPh(3))Au(alpha-diimine)]X, where NHC = IPr

Li, Lidong, Patricia S. Lopes, Vitor Rosa, Claudia A. Figueira, Amelia M. N. D. A. Lemos, Teresa M. Duarte, Teresa Aviles, and Pedro T. Gomes. "{Synthesis and structural characterisation of (aryl-BIAN)copper(I) complexes and their application as catalysts for the cycloaddition of azides and alkynes}." {DALTON TRANSACTIONS}. {41} (2012): {5144-5154}. Abstract

{{A series of Ar-BIAN-based copper(I) complexes (where Ar-BIAN = bis(aryl) acenaphthenequinonediimine) were synthesised and characterised by H-1 and C-13 NMR spectroscopies, FT-IR spectroscopy, MALDI-TOF-MS spectrometry, cyclic voltammetry and single crystal X-ray diffraction. The bis-chelated complexes of general formula {[}Cu(Ar-BIAN)(2)]BF4 (where Ar = C6H5 (1), 4-iPrC(6)H(4) (3), 2-iPrC(6)H(4) (4)) were prepared by reaction of {[}Cu(NCMe)(4)]BF4 with two equivalents of the corresponding Ar-BIAN ligands, in dichloromethane, while the mono-chelated complexes of the type {[}Cu(Ar-BIAN)L2]BF4 (where Ar = 2,6-iPr(2)C(6)H(3)

Kauf, Thomas, Vitor Rosa, Christophe Fliedel, Roberto Pattacini, Naina Deibel, Teresa Aviles, Biprajit Sarkar, and Pierre Braunstein. "{Reactivity of TCNE and TCNQ derivatives of quinonoid zwitterions with Cu(I)}." {DALTON TRANSACTIONS}. {44} (2015): {5441-5450}. Abstract

{The reactions of TCNE- and TCNQ-functionalized (TCNE: tetracyanoethylene and TCNQ: 7,7', 8,8'-tetra-cyanoquinodimethane) zwitterionic benzoquinonemonoimines with a Cu(I)-BIAN complex (BIAN = bis-(o, o'-bisisopropylphenyl)acenaphthenequinonediimine) have been investigated and found to follow a diversity of interesting patterns. The complexes {[}Cu(BIAN)(NCMe)(L2)]BF4 (2) and {[}Cu(BIAN)(L2)(2)]BF4 (4) were obtained by reacting {[}Cu(BIAN)(NCMe) 2] BF4 (1) with one and two equivalents of L2, respectively. Following similar procedures, the complexes {[}Cu(BIAN)(NCMe)(L3)] BF4 (6) and {[}Cu(BIAN)(L3)(2)]BF4 (7) were obtained by reaction of 1 with L3. The reaction of 2 with 0.5 equiv. of 4,4'-bipyridine afforded {[}\{Cu(BIAN)-(L2)\}(2)(mu-4,4'-bipyridine)](BF4)(2) (3). The complexes were characterized by multinuclear NMR, IR and UV-Vis spectroscopic techniques, mass spectrometry, cyclic voltammetry and elemental analysis. The molecular structures of complexes 3 center dot 4CH(2)Cl(2) and 4 center dot CH2Cl2 were determined by single crystal X-ray diffraction. An unexpected coordination polymer {[}Cu(L2(-))(2)](infinity) (5) was also structurally characterized, which contains Cu(II) centres chelated by two N, O-bound ligands resulting from the monodeprotonation of L2.}

Fliedel, Christophe, Vitor Rosa, Filipa M. Alves, Ana. M. Martins, Teresa Aviles, and Samuel Dagorne. "{P,O-Phosphinophenolate zinc(II) species: synthesis, structure and use in the ring-opening polymerization (ROP) of lactide, epsilon-caprolactone and trimethylene carbonate}." {DALTON TRANSACTIONS}. {44} (2015): {12376-12387}. Abstract

{The P, O-type phosphinophenol proligands (1 center dot H, 2-PPh2-4-Me-6-Me-C6H2OH; 2 center dot H, 2-PPh2-4-Me-6-Bu-t-C6H2OH) readily react with one equiv. of ZnEt2 to afford in high yields the corresponding Zn(II)ethyl dimers of the type {[}(kappa(2)-P, O) Zn-Et](2) (3 and 4) with two mu-O-Ph bridging oxygens connecting the two Zn(II) centers, as determined by X-ray diffraction (XRD) studies in the case of 3. Based on diffusion-ordered NMR spectroscopy (DOSY), both species 3 and 4 retain their dimeric structures in solution. The alcoholysis reaction of Zn(II) alkyls 3 and 4 with BnOH led to the high yield formation of the corresponding Zn(II) benzyloxide species {[}(kappa(2)-P, O) Zn-OBn](2) (5 and 6), isolated in a pure form as colorless solids. The centrosymmetric and dimeric nature of Zn(II) alkoxides 5 and 6 in solution was deduced from DOSY NMR experiments and multinuclear NMR data. Though the heteroleptic species 5 is stable in solution, its analogue 6 is instable in CH2Cl2 solution at room temperature to slowly decompose to the corresponding homoleptic species 8 via the transient formation of (kappa(2)-P, O)(2)Zn-2(mu-OBn)(mu-kappa(1):kappa(1)-P, O) (6'). Crystallization of compound 6 led to crystals of 6', as established by XRD analysis. The reaction of ZnEt2 with two equiv. of 1 center dot H and 2 center dot H allowed access to the corresponding homoleptic species of the type {[}Zn(P, O)(2)] (7 and 8). All gathered data are consistent with compound 7 being a dinuclear species in the solid state and in solution. Data for species 8, which bears a sterically demanding P, O-ligand, are consistent with a mononuclear species in solution. The Zn(II) alkoxide species 5 and the {[}Zn(P, O)(2)]-type compounds 7 and 8 were evaluated as initiators of the ring-opening polymerization (ROP) of lactide (LA), epsilon-caprolactone (epsilon-CL) and trimethylene carbonate (TMC). Species 5 is a well-behaved ROP initiator for the homo-, co- and terpolymerization of all three monomers with the production of narrow disperse materials under living and immortal conditions. Though species 7 and 8 are ROP inactive on their own, they readily polymerize LA in the presence of a nucleophile such as BnOH to produce narrow disperse PLA, presumably via an activated-monomer ROP mechanism.}

Schnee, Gilles, Christophe Fliedel, Teresa Aviles, and Samuel Dagorne. "{Neutral and Cationic N-Heterocyclic Carbene Zinc Adducts and the BnOH/Zn(C6F5)(2) Binary Mixture - Characterization and Use in the Ring-Opening Polymerization of beta-Butyrolactone, Lactide, and Trimethylene Carbonate}." {EUROPEAN JOURNAL OF INORGANIC CHEMISTRY}. {2013} (2013): {3699-3709}. Abstract

{{Abstract A variety of N-heterocyclic carbene (NHC) zinc adducts of the type NHC-ZnMe2 {[}2a

Vitor Rosa, Christophe Fliedel, Alessio Ghisolfi, Roberto Pattacini, Teresa Aviles, and Pierre Braunstein. "{Influence of a thioether function in short-bite diphosphine ligands on the nature of their silver complexes: structure of a trinuclear complex and of a coordination polymer}." {DALTON TRANSACTIONS}. {42} (2013): {12109-12119}. Abstract

{New cationic Ag(I) complexes were prepared by reaction of AgBF4 with two thioether-functionalized bis-(diphenylphosphino) amine ligands, Ph2PN(p-ArSMe)PPh2 (L1) and Ph2PN(n-PrSMe)PPh2 (L2), and compared with those obtained from the unfunctionalized ligands Ph2PN(Ph)PPh2 (L3) and Ph2PN(n-Bu)PPh2 (L4), respectively. The complex {[}Ag-3(mu(3)-Cl)(2)(mu(2)-L1-P, P)(3)](BF4) (1 center dot BF4) contains a triangular array of Ag centres supported by three bridging L1 ligands and two triply-bridging chlorides. In contrast, ligand L2 led to the coordination polymer {[}\{Ag-2(mu(3)-L2,-P,P,S)(2)(MeCN)(2)\}\{Ag-2(mu(2)-L2-P,P)(2)(MeCN)(2) \}(BF4)(4)](n) (2) in which the tethered thioether group connects intermolecularly a Ag2 unit to the diphosphine bridging the other Ag2 unit. With L3 and L4, two similar complexes were obtained, {[}Ag-2(mu(2)-L3)(BF4)(2)] (3) and {[}Ag-2(mu(2)-L4)(BF4)(2)] (4), respectively, with bridging diphosphine ligands and a BF4 anion completing the coordination sphere of the metal. Complexes 1 center dot BF4 center dot CH2Cl2, 2 center dot THF, 3 center dot 3CH(2)Cl(2) and 4 have been fully characterized, including by single crystal X-ray diffraction.}

Romain, Charles, Vitor Rosa, Christophe Fliedel, Frederic Bier, Frederic Hild, Richard Welter, Samuel Dagorne, and Teresa Aviles. "{Highly active zinc alkyl cations for the controlled and immortal ring-opening polymerization of epsilon-caprolactone}." {DALTON TRANSACTIONS}. {41} (2012): {3377-3379}. Abstract

{Zinc alkyl cations supported by N,N-BIAN-type bidentate ligands were found to be highly active in the immortal ROP of epsilon-caprolactone to yield narrowly disperse and chain length-controlled poly(epsilon-caprolactone), whether in solution or bulk polymerization conditions.}

Fliedel, Christophe, Gilles Schnee, Teresa Aviles, and Samuel Dagorne. "{Group 13 metal (Al, Ga, In, Tl) complexes supported by heteroatom-bonded carbene ligands}." {COORDINATION CHEMISTRY REVIEWS}. {275} (2014): {63-86}. Abstract

{The present contribution comprehensively reviews the synthesis, structural characterization and current applications of group 13 metal complexes supported by heteroatom-bonded carbene ligands. Detailed structural analysis and comparison of the structure/reactivity trends of group 13 metal carbene species constitute the primary purpose of the present contribution. The current use and applications of this class of compounds are also discussed. In general, such adducts have been thoroughly characterized (both in solution or in the solid state) and structural data, frequently supported by theoretical investigations, provided insight into the stability/reactivity of the adducts formed. While essentially dominated by Arduengo-type NHC adducts, N- and P-bonded cyclic and acyclic carbene complexes of Al, Ga and In have also been recently described, including the recent use of ``carbon(0) ligands{''}. In general, recent developments in carbene group 13 species exploit the improved stability of the resulting metal complexes for either the isolation/characterization of unprecedented structural motifs or the production of robust group 13 metal reagents subsequently used for organic substrates functionalization or in catalysis. (C) 2014 Elsevier B.V. All rights reserved.}

Fliedel, Christophe, Vitor Rosa, Carla I. M. Santos, Pablo J. Gonzalez, Rui M. Almeida, Clara S. B. Gomes, Pedro T. Gomes, Amelia M. N. D. A. Lemos, Gabriel Aullon, Richard Welter, and Teresa Aviles. "{Copper(II) complexes of bis(aryl-imino)acenaphthene ligands: synthesis, structure, DFT studies and evaluation in reverse ATRP of styrene}." {DALTON TRANSACTIONS}. {43} (2014): {13041-13054}. Abstract

{Two new Ar-BIAN Cu(II) complexes (where Ar-BIAN = bis(aryl-imino)acenaphthene) of formulations {[}CuCl2(Mes-BIAN)] (1) (Mes = 2,4,6-Me3C6H2) and {[}CuCl2(Dipp-BIAN)] (2) (Dipp = 2,6-iPr(2)C(6)H(3)) were synthesised by direct reaction of CuCl2 suspended in dichloromethane with the respective ligands Mes-BIAN (L1) and Dipp-BIAN (L2), dissolved in dichloromethane, under an argon atmosphere. Attempts to obtain these compounds by solubilising CuCl2 in methanol and adding a dichloromethane solution of the corresponding ligand, under aerobic conditions, gave also compound 1, but, in the case of L2, the Cu(I) dimer {[}CuCl(Dipp-BIAN)](2) (3) was obtained instead of compound 2. The compounds were fully characterised by elemental analyses, MALDI-TOF mass spectrometry, FT-IR, H-1 NMR and EPR spectroscopic techniques. The solid-state molecular structures of compounds 1-3 were determined by single crystal X-ray diffraction, showing the expected chelation of the Ar-BIAN ligands and two chloride ligands completing the coordination sphere of the Cu(11) centre. In the case of the complex 1, an intermediate coordination geometry around the Cu(II) centre, between square planar and tetrahedral, was revealed, while the complex 2 showed an almost square planar geometry. The structural differences and evaluation of energetic changes were rationalised by DFT calculations. Analysis of the electrochemical behaviour of complexes 1-3 was performed by cyclic voltammetry and the experimental redox potentials for Cu(II)/Cu(I) pairs have been compared with theoretical values calculated by DFT in the gas phase and in dichloromethane and methanol solutions. The complex 1 exhibited good activity in the reverse atom transfer radical polymerisation (ATRP) of styrene.}

Fliedel, Christophe, Samir Mameri, Samuel Dagorne, and Teresa Aviles. "{Controlled ring-opening polymerization of trimethylene carbonate and access to PTMC-PLA block copolymers mediated by well-defined N-heterocyclic carbene zinc alkoxides}." {APPLIED ORGANOMETALLIC CHEMISTRY}. {28} (2014): {504-511}. Abstract

{Four novel Zinc-NHC alkyl/alkoxide/chloride complexes (4, 5, 9 and 9) were readily prepared and fully characterized, including X-ray diffraction crystallography for 5 and 9. The reaction of N-methyl-N-butyl imidazolium chloride (3.HCl) with ZnEt2 (2 equiv.) afforded the corresponding {[}(CNHC)ZnCl(Et)] complex (4) via a protonolysis reaction, as deduced from NMR data. The alcoholysis of 4 with BnOH led to quantitative formation of the dinuclear Zn(II) alkoxide species {[}(CNHC)ZnCl(OBn)]2 (5), as confirmed by X-ray diffraction analysis. The NMR data are in agreement with species 5 retaining its dimeric structure in solution at room temperature. The protonolysis reaction of N-(2,6-diisopropylphenyl)-N-ethyl methyl ether imidazolium chloride (8.HCl) with ZnEt2 (2 equiv.) yielded the {[}(CNHC)ZnCl(Et)] species 9. The latter was found to be reactive with CH2Cl2 in solution and to cleanly convert to the corresponding Zn(II) dichloride {[}(CNHC)ZnCl2]2 (9), whose molecular structure was also elucidated using X-ray diffractometry. Unlike Zn(II)-NHC alkoxide species 1 and 2, which contain a NHC flanked with an additional N-functional group (i.e. thioether and ether, respectively), the Zn(II) alkoxide species 5 incorporates a monodentate NHC ligand. The Zn(II) complexes 1, 2 and 5 were tested in the ring-opening polymerization (ROP) of trimethylene carbonate (TMC). All three species are effective initiators for the controlled ROP of trimethylene carbonate, resulting in the production of narrow disperse PTMC material. Initiator 1 (incorporating a thioether moiety) was found to perform best in the ROP of TMC. Notably, the latter also readily undergoes the sequential ROP of TMC and rac-LA in the presence of a chain-transfer agent, leading to well-defined and high-molecular-weight PTMC/PLA block copolymers. Copyright (c) 2014 John Wiley & Sons, Ltd.}