- The reaction of rhenium(V) cores with a tetradentate schiff base. the isolation of 3+3 and 4+0 complexes of rhenium(V)
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The reaction of the potentially tetradentate N4-donor ligand N,N?-bis[(2-aminophenyl)methylidene]ethane-1,2-diamine (H2ane) with various rhenium(V) precursors led to the formation of different rhenium(V) complexes. With trans-[ReOBr
- Potgieter, Kim C.,Mayer, Peter,Gerber, Thomas I. A.
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- A comparison of the intramolecular and intermolecular hydrogen bonding of N,N′-ethylenebis(aminobenzylidene) in the solid state with its salen analogue
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The crystal structure of H2amben has been elucidated for the first time. The close NH?N contact between neighbouring molecules supports strongly the notion that intermolecular hydrogen bonding exists within the crystal lattice, creating a series of molecular chains, which are crosslinked in a three-dimensional array. This intermolecular bonding is suggested to account for the anomalously high melting point of H 2amben (176-178°C) compared to its H2salen counterpart (126-128°C). Although strong intramolecular forces are present in both ligands, H2salen contains no intermolecular hydrogen bonds.
- Gakias, Samantha,Rix, Colin,Fowless, Alan,Wills-Johnson, Graham,Latham, Kay,White, Jonathan
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- Novel chromium (III) complexes with N4-donor ligands as catalysts for the coupling of CO2 and epoxides in supercritical CO2
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New neutral and cationic chromium(III) complexes with N4 Schiff base ligands have been prepared and characterized. These complexes are active catalysts for the cycloaddition of CO2 and styrene oxide in CH 2Cl2 solutions, affording epoxide conversions in a 39-92% range, with encouraging cyclic carbonate yields (up to 63%). It is to notice that the cationic species were significantly more active than their neutral analogs. Addition of tetrabutylammonium halides improved the selectivity toward styrene carbonate (87% yield). Dichloromethane could be avoided using solvent free or supercritical carbon dioxide as a solvent (scCO2) and, moreover, this improved the catalytic activity of the cationic complexes (TOF up to 652 h-1). Using scCO2, these chromium catalysts afforded the rapid and selective formation of cyclic carbonates from the coupling of CO2 to various linear terminal epoxides, such as epichlorydrin, propylene oxide and long chain terminal oxiranes. Coupling of cyclohexene oxide and carbon dioxide led to mixtures of poly(cyclohexene) carbonate and cyclic carbonate depending on the conditions (pressure and co-catalyst/catalyst ratio). Poly(cyclohexene) carbonate was isolated with a productivity 388 g/g Cr. Selective formation of the cyclic cyclohexene carbonate was obtained working under scCO2 conditions.
- Cuesta-Aluja, Laia,Djoufak, Mary,Aghmiz, Ali,Rivas, Raquel,Christ, Lorraine,Masdeu-Bultó, Anna M.
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p. 161 - 170
(2013/12/04)
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- Synthesis and spectroscopic characterization of some copper(II) trinuclear complexes involving nitrogen as bridging atoms
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The following Schiff bases were employed as ligands in synthesizing Cu(II) trinuclear complexes: 1,2-bis-(2-aminobenzylideneamino) ethane (L1), 1,2-bis-(2-aminobenzylideneamino)propane (L2), 1,3-bis-(2-aminobenzylideneamino) propane (L3), 1,2-bis-(2- amin
- Annapoorani
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p. 3347 - 3351
(2012/07/31)
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