Search results for "coordination complex"
showing 10 items of 381 documents
Catalytic Asymmetric Formal [3+2] Cycloaddition of 2-Isocyanatomalonate Esters and Unsaturated Imines: Synthesis of Highly Substituted Chiral γ-Lacta…
2017
[EN] Unlike their isocyano and isothiocyanato analogues, isocyanato esters remain almost unexplored as formal 1,3-dipoles in asymmetric catalytic reactions. The first asymmetric formal [3+2] cycloaddition involving isocyanato esters and electrophilic alkenes is reported. Diisopropyl 2-isocyanatomalonate reacts with a,b-unsaturated N-(o-anisidyl) imines in the presence of a Mg(OTf)2¿BOX complex to give highly substituted chiral pyrrolidinones featuring a conjugate exocyclic double bond with excellent yields and enantiomeric excesses up to 99%. Several transformations of the resulting heterocycles, including the synthesis of a pyroglutamic acid derivative, have been carried out.
Syntheses and catalytic oxotransfer activities of oxo molybdenum(vi) complexes of a new aminoalcohol phenolate ligand.
2017
The new aminoalcohol phenol 2,4-di-tert-butyl-6-(((2-hydroxy-2-phenylethyl)amino)methyl)phenol (H2L) was prepared by a facile solvent-free synthesis and used as a tridentate ligand for new cis-dioxomolybdenum(vi)(L) complexes. In the presence of a coordinating solvent (DMSO, MeOH, pyridine), the complexes crystallise as monomeric solvent adducts while in the absence of such molecules, a trimer with asymmetric Mo[double bond, length as m-dash]O→Mo bridges crystallises. The complexes can catalyse epoxidation of cis-cyclooctene and sulfoxidation of methyl-p-tolylsulfide, using tert-butyl hydroperoxide as oxidant.
Selected cytotoxic gold compounds cause significant inhibition of 20S proteasome catalytic activities
2014
Abstract Six structurally diverse cytotoxic gold compounds are reported to cause profound and differential inhibition of the three main catalytic activities of purified 20S proteasome whilst auranofin , an established gold(I) drug in clinical use, is nearly ineffective. In particular, the gold(I) complex [( pbiH ) Au ( PPh 3 )] PF 6 , turns out to be the most potent inhibitor of all three enzyme activities with sub-micromolar IC 50 values. The present results further support the view that proteasome inhibition may play a major – yet not exclusive – role in the cytotoxic actions of gold based anticancer agents.
Frontiers of metal-coordinating drug design
2020
INTRODUCTION: The occurrence of metal ions in biomolecules is required to exert vital cellular functions. Metal-containing biomolecules can be modulated by small-molecule inhibitors targeting their metal-moiety. As well, the discovery of cisplatin ushered the rational discovery of metal-containing-drugs. The use of both drug types exploiting metal–ligand interactions is well established to treat distinct pathologies. Therefore, characterizing and leveraging metal-coordinating drugs is a pivotal, yet challenging, part of medicinal chemistry. AREA COVERED: Atomic-level simulations are increasingly employed to overcome the challenges met by traditional drug-discovery approaches and to compleme…
Slow Relaxation of the Magnetization in Anilato-Based Dy(III) 2D Lattices.
2021
The search for two- and three-dimensional materials with slow relaxation of the magnetization (single-ion magnets, SIM and single-molecule magnets, SMM) has become a very active area in recent years. Here we show how it is possible to prepare two-dimensional SIMs by combining Dy(III) with two different anilato-type ligands (dianions of the 3,6-disubstituted-2,5-dihydroxy-1,4-benzoquinone: C6O4X22−, with X = H and Cl) in dimethyl sulfoxide (dmso). The two compounds prepared, formulated as: [Dy2(C6O4H2)3(dmso)2(H2O)2]·2dmso·18H2O (1) and [Dy2(C6O4Cl2)3(dmso)4]·2dmso·2H2O (2) show distorted hexagonal honeycomb layers with the solvent molecules (dmso and H2O) located in the interlayer space and…
New Microbe Killers: Self-Assembled Silver(I) Coordination Polymers Driven by a Cagelike Aminophosphine
2019
New Ag(I) coordination polymers, formulated as [Ag(µ
Antibacterial studies, DNA oxidative cleavage, and crystal structures of Cu(II) and Co(II) complexes with two quinolone family members, ciprofloxacin…
2005
Nine coordination compounds of Cu(II) and Co(II) with Ciprofloxacin (HCp) and Enoxacin (HEx) as ligands have been prepared and characterized. Single crystal structural determinations of [Cu(HCp)2(ClO4)2].6H2O (1) and [Co(HEx)2(Ex)]Cl.2CH(3)OH.12H2O (4) are reported. The crystal of 1 is composed of [Cu(HCp)2(ClO4)2] units with the two perchlorate anions semicoordinated, and uncoordinated water molecules. The copper ion, at a crystallographic inversion centre, is in a tetragonally distorted octahedral environment. The structure of 4 consists of cationic monomeric [Co(HEx)2(Ex)]+ units, chloride anions, and uncoordinated methanol and water molecules. The complex is six-coordinate, with a sligh…
A cocrystal of two Mo(VI) complexes bearing different diastereomers of the 2,4-di-tert-butyl-6-{[(1-oxido-1-phenylpropan-2-yl)(methyl)amino]methyl}ph…
2013
The title cocrystal contains two chiral conformational diastereomers,viz.(1S,2R,RN)- and (1S,2R,SN)-, of [2,4-di-tert-butyl-6-{[(1-oxido-1-phenylpropan-2-yl)(methyl)amino]methyl}phenolato](methanol)-cis-dioxidomolybdenum(VI), [Mo(C25H35NO2)O2(CH3OH)], representing the first example of a structurally characterized molybdenum complex with enantiomerically pure ephedrine derivative ligands. The MoVIcations exhibit differently distorted octahedral coordination environments, with two oxide ligands positionedcisto each other. The remainder of the coordination comprises phenoxide, alkoxide and methanol O atoms, with an amine N atom completing the octahedron. The distinct complexes are linked by st…
Metal-organic magnets with large coercivity and ordering temperatures up to 242°C.
2020
International audience; Magnets derived from inorganic materials (e.g., oxides, rare-earth–based, and intermetallic compounds) are key components of modern technological applications. Despite considerable success in a broad range of applications, these inorganic magnets suffer several drawbacks, including energetically expensive fabrication, limited availability of certain constituent elements, high density, and poor scope for chemical tunability. A promising design strategy for next-generation magnets relies on the versatile coordination chemistry of abundant metal ions and inexpensive organic ligands. Following this approach, we report the general, simple, and efficient synthesis of light…
Zinc complexes as fluorescent chemosensors for nucleic acids: new perspectives for a “boring” element
2014
Zinc(ii) complexes are effective and selective nucleic acid-binders and strongly fluorescent molecules in the low energy range, from the visible to the near infrared. These two properties have often been exploited to quantitatively detect nucleic acids in biological samples, in both in vitro and in vivo models. In particular, the fluorescent emission of several zinc(ii) complexes is drastically enhanced or quenched by the binding to nucleic acids and/or upon visible light exposure, in a different fashion in bulk solution and when bound to DNA. The twofold objective of this perspective is (1) to review recent utilisations of zinc(ii) complexes as selective fluorescent probes for nucleic acid…