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Journal Article
Rosa, V., C. I. M. Santos, R. Welter, G. Aullon, C. Lodeiro, and T. Aviles. "Comparison of the Structure and Stability of New alpha-Diimine Complexes of Copper(I) and Silver(I): Density Functional Theory versus Experimental." Inorg Chem. 49 (2010): 8699-8708. AbstractWebsite

New compounds of the general formulas [M(Ar-BIAN)(2)]BF(4) and [M(Ar-BIAN)(NCMe)(2)]BF(4), where M=Cu(1) or Ag(1) and Ar-BIAN = bis(aryl)acenaphthenequinonediimine, were synthesized by the direct reaction of [Cu(NCMe)(4)]BF(4) or [Ag(NCMe)(4)]BF(4) with the corresponding Ar-BIAN ligand in dried CH(2)Cl(2). The synthesized compounds are [M(o, d, p-Me(3)C(6)H(2)-BIAN)(2)]BF(4) where M = Cu(1) (1) and Ag(1) (2), [M(o,d-iPr(2)C(6)H(3)-BIAN)(NCMe)(2)]BF(4) where M = Cu(1) (3) and Ag(1) (4), and [Ag(o,d-iPr(2)C(6)H(3)-BIAN)(2)]BF(4) (5). The crystal structures of compounds 1-3 and 5 were solved by singlecrystal X-ray diffraction. In all cases copper(I) or silver(I) are in a distorted tetrahedron that is constructed from the four nitrogen atoms of the two a-diimine ligands or, in 3, from one a-diimine ligand and two acetonitrile molecules. All compounds were characterized by elemental analyses, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, and IR, UV-vis, and (1)H NMR spectroscopy. The analysis of the molecular geometry and the energetic changes for the formation reactions of the complexes, in a CH(2)Cl(2) solution, were evaluated by density functional theory calculations and compared with the experimental results.

Sellin, M. F., I. Bach, J. M. Webster, F. Montilla, V. Rosa, T. Aviles, M. Poliakoff, and D. J. Cole-Hamilton. "Hydroformylation of alkenes in supercritical carbon dioxide catalysed by rhodium trialkylphosphine complexes." J Chem Soc Dalton (2002): 4569-4576. AbstractWebsite

Rhodium complexes modified by simple trialkylphosphines can be used to carry out homogeneous hydroformylation in supercritical carbon dioxide (scCO(2)). The catalyst derived from PEt3 is more active and slightly more selective for the linear products in scCO2 than in toluene, and under the same reaction conditions [100degreesC, 40 bar of CO/H-2 (1:1)] P(OPri)(3) is also an effective ligand giving good catalyst solubility and activity. Other ligands such as PPh3, POct(3), PCy3, and P(4-C6H4But)(3) are less effective because of the low solubility of their rhodium complexes in scCO(2). P(4-C6H4SiMe3)(n) Ph3-n (n = 3 or 1) and P(OPh)(3) impart activity despite their complexes only being poorly soluble in scCO(2). Under subcritical conditions, using PEt3 as the ligand, C7-alcohols from hydrogenation of the first formed aldehydes are the main products whilst above a total pressure of 200 bar, where the solution remains supercritical (monophasic) throughout the reaction, aldehydes are obtained with 97% selectivity. High pressure IR studies in scCO(2) using PEt3 as the ligand are reported.

Pedras, B., E. Oliveira, H. Santos, L. Rodriguez, R. Crehuet, T. Aviles, J. L. Capelo, and C. Lodeiro. "A new tripodal poly-imine indole-containing ligand: Synthesis, complexation, spectroscopic and theoretical studies." Inorg Chim Acta. 362 (2009): 2627-2635. AbstractWebsite

A novel flexible tripodal ligand derived from 3-methylindole, ("InTREN" L), and its mononuclear Zn(II), Cu(II), Ni(II), Hg(II) and Pd(II) complexes are described. All compounds gave analytically pure solid samples. Characterisation of the compounds was accomplished by (1)H NMR, IR and absorption spectroscopies, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and elemental analysis and their geometry optimized using density functional theory (DFT).Time-dependent-density functional theory (TD-DFT) calculations have been used to assign the lowest energy absorption bands of the free ligand and the Zn(II) complex. The system is a very good candidate for in situ recognition/coordination effects by MALDI-TOF-MS spectrometry and absorption spectroscopy. The presence of three indole groups in InTREN opens up the possibility to synthesize new three-dimensional self-assembly supramolecular structures. (C) 2008 Elsevier B.V. All rights reserved.

Casimiro, T., F. Montilla, S. Garcia, T. Aviles, S. Raeissi, A. Shariati, C. J. Peters, M. N. da Ponte, and A. Aguiar-Ricardo. "Phase behaviour of the catalyst dicarbonyl (eta(5)-cyclopentadienyl)-cobalt in carbon dioxide." J Supercrit Fluid. 31 (2004): 1-8. AbstractWebsite

The phase behaviour of the binary mixture of carbon dioxide and the cobalt complex dicarbonyl(eta(5)-cyclopentadienyl)-cobalt, CPCo(CO)(2), has been investigated. This organometallic compound is one of the most effective catalysts of cyclotrimerization reactions of arylisocyanates and alkynes. Vapour-liquid equilibrium (VLE) measurements were undertaken in a static analytical apparatus at 313.15, 323.15 and 363.15 K at pressures up to 15 MPa. p, T isopleths were measured by a synthetic method in a Cailletet apparatus. Nine different compositions ranging from 17.56 to 94.23 mol% of CO2 were measured up to 15 MPa. Modelling with the Peng-Robinson equation of state (PR EOS) gave reasonable results in the correlation of the experimental phase equilibrium compositions using two temperature-dependent interaction parameters. (C) 2003 Elsevier B.V. All rights reserved.

Pedras, B., H. M. Santos, L. Fernandes, B. Covelo, A. Tamayo, E. Bertolo, J. L. Capelo, T. Aviles, and C. Lodeiro. "Sensing metal ions with two new azomethine-thiophene pincer ligands (NSN): Fluorescence and MALDI-TOF-MS applications." Inorg Chem Commun. 10 (2007): 925-929. AbstractWebsite

The two new pincer azomethine-thiophene ligands (N,NE',N,NE')-N,N'-(thiophene-2,5-diylbis(methan-1-yl-1-ylidene))bis(naphathalen-2-ylmethanamine) (L1) and (E)-(4,6-dihydropyren-1-yl)-N-((5-((E)-(pyren-1-ylmethylimino)ethyl)thiophen-2-yl)methylene)methanamine (L2), their absorption, fluorescence and MALDI-TOF-MS spectroscopic studies are described. The two systems synthesised combine the emissive probes pyrene and naphthyl with the good chelating properties of a tridentate SN2 donor-set from a thiophene Schiff-base ligand. Both ligands gave analytically pure solid complexes with Ni(II) and Pd(II) salts. The bichromophoric pyrene derivative L2 presents two emission bands in solution, one corresponding to the monomer species and a red-shifted band attributable to the intramolecular excimer. Ni(II) and Pd(II) complexation affects the conformation in solution, increasing the monomer emission at the expense of the excimer band; this effect could be explored in metal ion sensing. System L1 behaves as a non emissive probe. In situ complexation reactions followed by MALDI-TOF-MS spectrometry without matrix support have also been performed; these experiments show that L1 could be a potential chemosensor for Ni(II) and Pd(11). (c) 2007 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, 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.}

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

Maiti, Biplab K., Luisa B. Maia, Kuntal Pal, Bholanath Pakhira, Teresa Aviles, Isabel Moura, Sofia R. Pauleta, Jose L. Nunez, Alberto C. Rizzi, Carlos D. Brondino, Sabyasachi Sarkar, and Jose J. G. Moura. "{One Electron Reduced Square Planar Bis(benzene-1,2-dithiolato) Copper Dianionic Complex and Redox Switch by O-2/HO-}." {INORGANIC CHEMISTRY}. {53} (2014): {12799-12808}. Abstract

{The complex {[}Ph4P](2){[}Cu(bdt)(2)] (1(red)) was synthesized by the reaction of {[}Ph4P]2{[}S2MoS2CuCl] with H2bdt (bdt = benzene-1,2-dithiolate) in basic medium. 1(red) is highly susceptible toward dioxygen, affording the one electron oxidized diamagnetic compound {[}Ph4P]{[}Cu(bdt)(2)] (1(ox)). The interconversion between these two oxidation states can be switched by addition of O-2 or base (Et4NOH = tetraethylammonium hydroxide), as demonstrated by cyclic voltammetry and UV-visible and EPR spectroscopies. Thiomolybdates, in free or complex forms with copper ions, play an important role in the stability of 1(red) during its synthesis, since in its absence, 1(ox) is isolated. Both 1(red) and 1(ox) were structurally characterized by X-ray crystallography. EPR experiments showed that 1(red) is a Cu(II)-sulfur complex and revealed strong covalency on the copper-sulfur bonds. DFT calculations confirmed the spin density delocalization over the four sulfur atoms (76%) and copper (24%) atom, suggesting that 1(red) has a ``thiyl radical character{''}. Time dependent DFT calculations identified such ligand to ligand charge transfer transitions. Accordingly, 1(red) is better described by the two isoelectronic structures {[}Cu(I)(bdt(2), 4S(3-{*}))](2-) {[}Cu-II(bdt(2), 4S(4-))](2-). On thermodynamic grounds, oxidation of 1(red) (doublet state) leads to 1(ox) singlet state, {[}Cu-III(bd(t)2, 4S(4-))](1-).}

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.}