Search results for "tripodal ligand"
showing 10 items of 14 documents
A New Rhodium(III) Complex with a Tripodal Bis(imidazolylidene) Ligand. Synthesis and Catalytic Properties
2003
A new bis(imidazolylidene) tripodal ligand has been obtained by a simple method. The coordination of this ligand to Rh provides the first Rh(III) complex with a bis(carbene) ligand in a tripodal coordination, and its catalytic properties toward hydrogen transfer have been examined.
The [Pd(bipy)]2+ “merry-go-round”: Insights into the lability of the Pd–N bond
2009
Abstract Two tripods (1 and 2) featuring pyrimidinyl pendant arms have been synthesized from 5-(1H-pyrazol-3-yl)-pyrimidine (5) and 1,3,5-tribromomethylbenzene derivatives. Reaction with three equivalents of [Pd(bipy)](NO3)2 to form a macrotricycle closed by palladium coordination unexpectedly afforded the mononuclear species [Pd(1)(bipy)]2+ and [Pd(2)(bipy)]2+. These complexes show fluxional behavior on the 1H NMR timescale, the [Pd(bipy)]2+ fragment hopping between the pyrimidinyl coordinating moieties. The ΔGc‡’s estimated by the coalescence method are temperature independent, which means that ΔSc‡ = 0. This indicates that the “merry-go-round” process of [Pd(bipy)]2+ occurs intramolecula…
Synthesis of a New C3-Symmetric Tripodal P4-Tetradentate Ligand and Its Application to the Formation of Chiral Metal Complexes
2010
A novel C3-symmetric tetradentate tripodal ligand with phosphorus as coordinating atoms has been synthesized in good yields. Its coordination ability through the four phosphorus atoms, three at the...
A new pyridine-bis-N-heterocyclic carbene ligand and its coordination to Rh: Synthesis and characterization
2005
Abstract The new bis(imidazolylidene) tripodal ligand precursor (2-pyridine)bis(3-methylimidazolium-1-yl)methane diiodide, [H2PYBIMMe]I2, has been obtained by a simple method. The molecular structure of this new ligand precursor has been determined by means of X-ray diffraction. The coordination of this ligand to Rh, provides a Rh(III) complex with very low solubility in most solvents, which we attributed to the polymeric nature of the species. Solution of this polymer in DMSO provided a biscarbene Rh(III) complex in which the pyridine fragment remained unbound.
Ti(iv)-amino triphenolate complexes as effective catalysts for sulfoxidation
2010
C 3 -symmetric Ti (IV) amino triphenolate complexes efficiently catalyze, without previous activation and in excellent yields, the oxidation of sulfides at room temperature, using both CHP and the more environment friendly aqueous hydrogen peroxide as terminal oxidants, with catalyst loadings down to 0.01%. The Ti(IV) catalysts and the intermediate Ti(IV)-peroxo complexes have been characterized in solution by 1H NMR and ESI-MS techniques and via density functional studies.
Kinetic study of the oxidation of [Fe(CN)6]4− by [Co(NH3)4pzCO2]2+ and S2O82- in the presence of the tripodal ligand Tren Aminopropil
2011
Abstract Oxidations (electron transfers) of [Fe(CN)6]4− by [Co(NH3)4pzCO2]2+ and S 2 O 8 2 - have been studied in solutions containing the receptor N,N′,N″-(aminopropil)-tris (2-aminoetil) amina [Tren Aminopropil, TAL], which can incorporate [Fe(CN)6]4− and S 2 O 8 2 - but not the cobalt complex. The results can be explained using the Bronsted equation that allows to obtain the binding constant of the transition state, a parameter that the Pseudophase Model cannot provide.
Mononuclear and binuclear copper(II) complexes with bis(2-imidazolyl)(bis(methoxycarbonyl)methylmethane) (BIBM), a tripodal bis(imidazole) based liga…
2013
Two new Cu(II) complexes with bis(2-imidazolyl) (bis(methoxycarbonyl)methylmethane) (BIBM), a tridentate bis(imidazole) based ligand with the formula [Cu(BIBM) 2 ](ClO 4 ) 2 ( 1 ) and [{Cu(BIBM)(H 2 O)} 2 (μ 1,2,3,4 -C 2 O 4 )](C 4 O 4 )·6H 2 O ( 2 ) have been synthesized and characterized. Compound 1 shows mononuclear cationic [Cu(BIBM) 2 ] 2+ units and perchlorate ions. The coordination around the Cu(II) ion shows a tetragonally-elongated octahedral geometry. The BIBM ligand acts as a k 3 -N,N’,O tripodal ligand, through two imidazole N atoms and a weak Cu–O(carboxymethyl) axial interaction. In the crystal structure cations and anions connect through H-bonds generating linear chains. Line…
AC3-Symmetric Palladium Catalyst with a Phosphorus-Based Tripodal Ligand
2006
Cis- and trans molybdenum oxo complexes of a prochiral tetradentate aminophenolate ligand : Synthesis, characterization and oxotransfer activity
2020
Abstract Reaction of [MoO2Cl2(dmso)2] with the tetradentate O2N2 donor ligand papy [H2papy = N-(2-hydroxybenzyl)-N-(2-picolyl)glycine] leads to formation of the dioxomolybdenum(VI) complex [MoO2(papy)] (1) as a mixture of cis and trans isomers. Recrystallization from methanol furnishes solid cis-1, whereas the use of a dichloromethane-hexane mixture allows for the isolation of the trans-1 isomer. Both isomers have been structurally characterized by X-ray crystallography and the energy difference between the isomeric pair has been investigated by electronic structure calculations. Optimization of two configurational isomers in the gas phase predicts the trans isomer to lie 2.5 kcal/mol lower…
A chiral diamine bis-phenolate complex of dioxomolybdenum(VI)
2009
Abstract A new dioxomolybdenum(VI) complex with a chiral tetradentate ligand is reported. The tripodal ligand containing two nitrogen atoms and two phenolic oxygen atoms was synthesized starting from a chiral diamine precursor. Further reaction with [MoO2(acac)2] yielded a monomeric molybdenum complex as a bright yellow solid. The structures of the molybdenum complex and the free diamine bis-phenol ligand were determined by X-ray diffraction.