Search results for " complex"
showing 10 items of 3391 documents
ortho-Metalation of aromatic ethers by yttrium alkyl complexes that contain a linked amido-cyclopentadienyl ligand
2003
Abstract The reaction of the half-sandwich alkyl complex [Y(η5:η1-C5Me4CH2SiMe2NtBu)(CH2SiMe3)(THF)] (1) with anisole smoothly gives the ortho-metalation product [Y(η5:η1-C5Me4CH2SiMe2NtBu)(2-C6H4OMe)(THF)] (2). 3- and 4-Methylanisole as well as phenetole analogously undergo ortho-metalation, whereas thioanisole, N,N′-dimethylaniline, fluorobenzene, and trifluorobenzene do not react with yttrium complex 1. 2-Methylanisole reacts with 1 under activation of the ring methyl group to give the 2-methoxybenzyl complex [Y(η5:η1-C5Me4CH2SiMe2NtBu)(CH2C6H4OMe-2)(THF)] (6). A single-crystal X-ray structure analysis of the 2-anisyl complex 2 revealed a four-legged piano-stool configuration with the me…
Oxamato-based coordination polymers: recent advances in multifunctional magnetic materials
2014
The design and synthesis of novel examples of multifunctional magnetic materials based on the so-called coordination polymers (CPs) have become very attractive for chemists and physicists due to their potential applications in nanoscience and nanotechnology. However, their preparation is still an experimental challenge, which requires a deep knowledge of coordination chemistry and large skills in organic chemistry. The recent advances in this field using a molecular-programmed approach based on rational self-assembly methods which fully exploit the versatility of the coordination chemistry of the barely explored and evergreen family of N-substituted aromatic oligo(oxamato) ligands are prese…
Ligand design for multidimensional magnetic materials: a metallosupramolecular perspective.
2008
The aim and scope of this review is to show the general validity of the ‘complex-as-ligand’ approach for the rational design of metallosupramolecular assemblies of increasing structural and magnetic complexity. This is illustrated herein on the basis of our recent studies on oxamato complexes with transition metal ions looking for the limits of the research avenue opened by Kahn's pioneering research twenty years ago. The use as building blocks of mono-, di- and trinuclear metal complexes with a novel family of aromatic polyoxamato ligands allowed us to move further in the coordination chemistry-based approach to high-nuclearity coordination compounds and high-dimensionality coordination po…
Cluster dirhenium(III) cis-dicarboxylates with α-amino acids ligands as mighty selective G4s binders.
2021
The synthesis of four dirhenium(III) cis-dicarboxylates with the α-amino acids residues Asp (I), Glu (II), Phe (III) and Tyr (IV) is presented. The G-quadruplex stabilization potential was evaluated by fluorescence resonance energy transfer - melting analysis. All derivatives show specific binding to c-kit1 quadruplex, while II and IV have also strong stabilization activity to HTelo21 quadruplex. At the same time, the compounds do not show any stabilization activity for ds26 DNA, which suggests unique mechanisms of molecular DNA recognition for these complexes.
Improved Preparations of Molybdenum Coordination Compounds from Tetrachlorobis(diethyl ether)molybdenum(IV)
2001
International audience; The reduction of MoCl5 with metallic tin in diethyl ether provides a rapid and convenient entry to [MoCl4(OEt2)2] This compound can be transformed easily and in high yields into a variety of other useful synthons. The loss of ether in the solid state affords a new and reactive form of MoCl4. Treatment with THF, PMe3 or LiOtBu affords [MoCl4(THF)2], [MoCl4(PMe3)3] or [Mo(OtBu)4] in high isolated yields. Treatment with metallic tin in THF affords [MoCl3(THF)3] All of these reactions can be carried out under simple experimental conditions and represent significant improvements relative to previously reported syntheses of the same compounds.
Towards Adoptive Immunotherapy Using High Affinity T Cell Receptors
2003
The hdm2 oncoprotein is frequently overexpressed in a variety of human malignancies, including acute myeloid and lymphoblastic leukemia. Synthetic peptides representative of hdm2 sequences were tested for their binding to A2.1. HLA-A2.1. (/Kb)-Tg mice were immunized with A2.1-binding hdm2 peptides in order to induce A2.1-restricted and hdm2-specific CTL. A2.1-restricted CTL lines obtained from both A2.1 and HuCD8 × A2.1/Kb-Tg mice were able to recognize a synthetic 8-mer peptide representative of a N-terminal hdm2 sequence. These CTL were capable of recognizing and lysing Saos-2 cells transfected with the hdm2 gene as opposed to the parental cell line that lacks any detectable hdm2 expressi…
Synthesis and magnetic properties of an iron 1,2-bisthienyl perfluorocyclopentene photochromic coordination compound
2011
Abstract The coordination compound Fe(BM-4-PTP) 2 (NCS) 2 ⋅2MeOH ( 1 ) including the photoisomerizable ligand BM-4-PTP (1,2-bis(2′-methyl-5′-(pyrid-4″-yl)thien-3′-yl)perfluorocyclopentene) was obtained as an orange powder. The powder turns blue upon photocyclization of the 1,2-bisthienyl photochromic ligand induced by UV light irradiation at room temperature. Photocycloreversion is obtained by visible light irradiation of the material in the solid state. The orange and blue powders were investigated over the temperature range (5–293 K) and pressure range (1 bar–12 kbar) by magnetic susceptibility measurements and variable temperature 57 Fe Mossbauer spectroscopy. The photo-induced colour ch…
Multifunctional magnetic materials obtained by insertion of a spin-crossover Fe(III) complex into bimetallic oxalate-based ferromagnets.
2010
The syntheses, structures and magnetic properties of the compounds of formula [Fe(III)(sal(2)-trien)][Mn(II)Cr(III)(ox)(3)].CH(2)Cl(2) (1; H(2)sal(2)-trien=N,N'-disalicylidenetriethylenetetramine, ox=oxalate), [Fe(III)(sal(2)-trien)][Mn(II)Cr(III)(ox)(3)].CH(3)OH (2), [In(III)(sal(2)-trien)][Mn(II)Cr(III)(ox)(3)].0.25H(2)O.0.25CH(3)OH.0.25CH(3)CN (3), and [In(III)(sal(2)-trien)][Mn(II)Cr(III)(ox)(3)].CH(3)NO(2).0.5H(2)O (4) are reported. The structure of 1 presents a 2D honeycomb anionic layer formed by Mn(II) and Cr(III) ions linked through oxalate ligands and a cationic layer of [Fe(sal(2)-trien)](+) complexes intercalated between the 2D oxalate network. The structures of 2, 3, and 4 pres…
Proton-dependent kinetics of citrate uptake in growing cells ofLactococcus lactissubsp.lactisbv.diacetylactis
1995
The kinetic analysis of citrate uptake in growing cells of Lactococcus lactis subsp. lactis biovar. diacetylactis identified a proton-dependent transport and suggested the divalent anionic species as the form of citrate transported across cell membranes. The reaction followed Michaelis-Menten kinetics for a two-substrate reaction. The limiting steps were the formation of the ternary complex and the rate of transport. Temperature modified the activity of the permease, increasing the uptake rate.
Pressure effect studies on spin crossover systems
2005
Abstract In the present review article we discuss the results of investigations of the influence of hydrostatic pressure (up to 1.2 GPa) on the spin transition behaviour in coordination compounds of 3d transition metal ions. The systems under investigation are mononuclear spin crossover compounds of iron(II) and chromium(II), dinuclear complexes of iron(II) exhibiting coexistence of intramolecular anti-ferromagnetic coupling and thermal spin crossover, and 1D, 2D and 3D polynuclear spin crossover complexes of iron(II). It is demonstrated that the application of hydrostatic pressure serves as a tool for modifying the ligand field strength in a controlled manner.