Search results for "COPP"
showing 10 items of 3147 documents
Crystal and molecular structure of tris(mepirizole) copper(II) hexafluorophosphate [mepirizole = 4-methoxy-2-5-methoxy-3-methyl-1h-pyrazol-1-yl)-6-me…
1992
Abstract The X-ray crystal structure of Cu(mep)3(PF6)2 [mep = mepirizole or 4-methoxy-2-(5-methoxy-3-methyl-1H-pyrazol-1-yl)-6 methylpyrimidine], obtained from stoichiometric quantities of mep, Cu(NO3)2 and KPF6 in water/ethanol solution was determined. The trisbidentate Cu(mep)32+ cation is observed for the first time. One of the three mep molecules is disordered over two sets of positions related by crystallographic symmetry. The mep molecules exhibit two different conformations A and B: conformation B, which is observed for the first time, derives from the usual conformation A by rotating the pyrimidine ring by 180° around the central CN bond and rotating by 180° the methoxy group bonde…
Coordination abilities of l-glutamic acid γ-monohydroxamic acid towards copper(II) in the absence and presence of some aliphatic amines
2012
Abstract Solution equilibrium studies on the Cu 2+ –(A)–(Glu-γ-ha) ternary systems ((A) = polyamine: ethylenediamine (en), diethylenetriamine (dien), N , N , N ′, N ″, N ″-pentamethyldiethylenetriamine (Me 5 dien); (Glu-γ-ha) = l -glutamic-γ-hydroxamic acid) have been performed by pH-potentiometry, UV–Vis spectrophotometry and EPR methods. The obtained results suggest the formation of the heteroligand complexes with [Cu(A)(Glu-γ-ha)] + stoichiometry in all studied systems. Our spectroscopic results indicate the tetragonal geometry for the [Cu(en)(Glu-γ-ha)] + species in which Glu-γ-ha acts as a tridentate ligand, the geometry slightly deviated from square pyramidal for [Cu(dien)(Glu-γ-ha)]…
Fluoroquinolone–metal complexes: A route to counteract bacterial resistance?
2014
Abstract Microbial resistance to antibiotics is one of the biggest public health threats of the modern world. Antibiotic resistance is an area of much clinical relevance and therefore research that has the potential to identify agents that may circumvent it or treat resistant infections is paramount. Solution behavior of various fluoroquinolone (FQ) complexes with copper(II) in the presence and absence of 1,10-phenanthroline (phen) was studied in aqueous solution, by potentiometry and/or spectrophotometry, and are herein described. The results obtained showed that under physiological conditions (micromolar concentration range and pH 7.4) only copper(II):FQ:phen ternary complexes are stable.…
Structural, magnetic, and spectroscopic comparative studies on four new derivatives of DIMMAL (2-di1H-2-imidazolylmethylmalonate): a novel generator …
2005
This paper reports the synthesis, structure solution, and magnetic characterization of four new DIMMAL-containing compounds (H 2 DIMMAL = 2-di1H-2-imidazolylmethylmalonic acid), H 2 DIMMAL.H 2 O (1), Na 2 (DIMMAL).5H 2 O (2), [Cu(HDIMMAL) 2 ] (3), and [Cu 2 (DIMMAL) 2 (H 2 O) 2 ].2H 2 O (4). Compound 1, containing two carboxylates and two protonated imidazole rings, adopts the dizwitterion configuration. These monohydrate MBBs pack together into a 3D array driven, as in the other three cases herein reported, by a combination of multiple-path H-bonds and aromatic-aromatic interactions. Compound 2 consists of centrosymmetric Na + tetramers in which four NaO 6 distorted octahedra are interconn…
Self-assembly of 1D- and 3D-networks through non-coordination intermolecular forces: synthesis and crystal structures of copper(I) complexes based on…
2007
Reaction of [Cu2(H3CCN)2(μ-pydz)3][PF6]2 (1) with an excess of pyridazine or phthalazine yielded the novel dinuclear complexes [Cu2(μ-pydz)3(pydz)2][PF6]2 (2) and [Cu2 (μ- pydz)(μ-phtz)2(phtz)2][PF6]2 (5), respectively. Depolymerisation of the coordination polymer 1 ∞ {[Cu(μ-pydz)2][PF6]} (3) in dichloromethane by addition of an excess of benzo[c]cinnoline afforded the dinuclear copper(I) salt [Cu2(μ-pydz)2(pydz)2(benzo[c]cinnoline)2][PF6]2 (4). Furthermore, a new route for the preparation of bis(benzonitrile)tris(μ-phthalazine)dicopper(I) bis(trifluoromethanesulfonate), [Cu2(C6H5CN)2(μ-phtz)3][CF3SO3]2 (7), was established from {[Cu(CF3SO3)]2 ・C6H5Me}, phthalazine and benzonitrile via the …
A new tetranuclear copper(I) complex based on allyl(5-phenyl-1,3,4-thiadiazol-2-yl)azanide ligand: Synthesis and structural characterization
2015
Abstract By means of alternating current electrochemical technique a new tetranuclear crystalline copper(I) complex [Cu I 4 ( L − ) 4 ] ( L − – allyl(5-phenyl-1,3,4-thiadiazol-2-yl)azanide ion) has been obtained and characterized by X-ray single crystal diffraction ( Sp. gr. I 4 1 / a ) and Raman spectroscopy. The metal center adopts linear arrangement, composed of one thiadiazole N atom from the one L − anion and one azanide N atom of the other L − ligand. A bridged Cu atoms stitch four L − ligands into the firstly observed tetranuclear copper(I) azanide complex with intramolecular Cu(I)⋯Cu(I) interactions at the distance of 2.7451(6) A. Molecular structure and Raman spectrum of the compo…
Detection of Single Oxygen Molecules with Fluorescence-Labeled Hemocyanins
2005
This study introduces a method to detect individual oxygen molecules by fluorescence microscopy of single hemocyanins. These respiratory proteins from a tarantula bind oxygen with high affinity. A spectrometric signature of the oxygenated protein is transferred to an attached fluorescence label, which can be detected at the single-molecule level. This technique opens new perspectives for the development of small and sensitive oxygen sensors as well as for the investigation of cooperative oxygen binding in respiratory proteins.
Peptide Metal–Organic Frameworks for Enantioselective Separation of Chiral Drugs
2017
We report the ability of a chiral Cu(II) 3D MOF based on the tripeptide Gly-L-His-Gly (GHG) for the enantioselective separation of metamphetamine and ephedrine. Monte Carlo simulations suggest that chiral recognition is linked to preferential binding of one of the enantiomers as result of either stronger or additional H-bonds with the framework that lead to energetically more stable diastereomeric adducts. Solid phase extraction (SPE) of a racemic mixture by using Cu(GHG) as extractive phase permits isolating more than 50% of the (+)-ephedrine enantiomer as target compound in only four minutes. To the best of our knowledge, this represents the first example of a MOF capable of separating ch…
Activation of the Cyano Group at Imidazole via Copper Stimulated Alcoholysis
2019
Reactions of 4,5-dicyano-1-methylimidazole with CuX2 (X = Cl, Br) in alcohol solvents (ethanol and methanol) resulted in the formation of Cu(II) carboximidate complexes [CuCl2(5- cyano-4-C(OEt)N-1-methylimidazole)(EtOH)] (1), [Cu2(µ
DNA interaction of new copper(II) complexes with sulfonamides as ligands
2007
New copper(II) complexes with sulfonamide ligands have been prepared and characterized. Sulfonamide ligands were prepared through a reaction between 8-aminoquinoline and either 2-mesitylene (Hqmesa), 4-tert-butylbenzene (Hqtbsa), or alpha-toluene (Halphaqtsa) sulfonyl chlorides. The structural analysis carried out for complex [Cu(alphaqtsa)(2)] indicated that the local environment of the Cu(II) cation is between a square planar and a tetrahedral geometry, with stacking of the benzene rings of the sulfonyl ligands between neighbor molecules. Powder EPR spectra at room temperature gave rhombic spectra for the [Cu(alphaqtsa)(2)] and [Cu(qmesa)(2)] complexes and an axial spectrum for the [Cu(qt…