Search results for " Geometry"
showing 10 items of 2294 documents
Dehydrotriphenylene zum Aufbau gewinkelter molekularer Bandstrukturen
1998
Dehydrotriphenylenes for the Generation of Bent Molecular Ribbons The synthetic sequences 1 11 and 17 23a lead to highly reactive mono- and bisdienophiles whose cycloaddition processes with in situ generated isobenzofuran 13 were studied: 11 + 13 15 and 23a + 2×13 24a.
4-[3-(4-Fluorophenyl)-5-isopropylisoxazol-4-yl]pyridine
2006
The molecular structure of the title compound, C17H15FN2O, was determined in the course of our studies on mitogen-activated protein kinase inhibitors. The exocyclic bond angles at the carbon atoms of the isoxazole ring bearing the pyridyl and 4-fluorophenyl rings are 130.0 (2) and 129.2 (2)°, respectively. The pyridine and 4-fluorophenyl rings are twisted relative to the isoxazole ring by 80.2 (2) and 19.1 (1)°, respectively.
4-[5-(4-Fluorophenyl)-3-isopropylisoxazol-4-yl]pyridine
2006
In the title compound, C17H15FN2O, the exocyclic bond angles at the C atoms of the isoxazole ring bearing the pyridyl and 4-fluorophenyl substituents are 129.66 (17) and 134.58 (16)°, respectively. The structure was determined in a study of the molecular geometry of isoxazole derivatives with biological activity as MAPK inhibitors.
Synthesis and pharmacological activity of silyl isoxazolines 2
2003
Silyl isoxazolines have been synthesized by [2+3] cycloaddition reaction of nitrile oxides to vinyl- and allylsilanes. The addition of 3-pyridylnitrile oxide to 1,3-divinyl-1,1,3,3-tetraphenyldisiloxane affords 1,3-bis{5-[3-(3-pyridyl)isoxazolin-2-yl]}-1,1,3,3-tetraphenyldisiloxane; the latter exists as a mixture of trans- and cis-isomers.The bond angle of the Si–O–Si fragment in thetrans-isomer equals 180(3)° and in the cis-isomer it is 162(3)°.The pharmacological properties of 4-[3-(5-trimethylsilylisoxazolin-2-yl)]pyridinium-chloride have been studied.
Equilibrium and spectroscopic studies of diethyltin(iv) complexes formed with hydroxymono- and di-carboxylic acids and their thioanalogues
2002
The complex formation of diethyltin(IV) cation with glycolic (GA), lactic (LA), succinic (SA), malic (MA), tartaric (TA), mercaptoacetic (MAA), 2-mercaptopropionic (MPA), mercaptosuccinic (MSA) and dimercaptosuccinic acid (DMSA) has been investigated by potentiometric, spectrophotometric, 1H NMR and Mossbauer spectroscopic methods. The mercaptocarboxylic acids yielded much more stable complexes than the corresponding hydroxy acids. Below pH 3, the carboxylate and the still protonated hydroxyl group of hydroxy acids are co-ordinated to the metal ion, while in the case of their thio analogues, {COO−, S−} co-ordinated species are dominant. With increasing pH, the metal promoted deprotonation o…
Towards oxalate-bridged iron(ii), cobalt(ii), nickel(ii) and zinc(ii) complexes through oxotris(oxalato)niobate(v): an open air non-oxidizing synthet…
2018
Four compounds with the formula [M2(dmphen)4(μ-C2O4)](ClO4)2·2dmso [M = Fe (1), Co (2) and Zn (4); dmphen = 2,9-dimethyl-1,10-phenanthroline] and [Ni2(dmphen)4(μ-C2O4)]3[NbO(C2O4)3]2·16H2O (3) have been synthesized using the tris(oxalato)oxoniobate(V) complex anion as the oxalate source, and their structures have been determined by single crystal X-ray diffraction. X-ray quality crystals of highly insoluble oxalate-bridged species were obtained by taking advantage of the slow release of oxalate by the tris(oxalato)oxoniobate(V) complex anion. The structures of 1–4 all contain oxalate-bridged dimetal(II) units with didentate dmphen molecules acting as end-cap ligands; electroneutrality is ac…
ChemInform Abstract: New Binary Antimonide Hf5Sb3 - Differences and Similarities to the Zr Antimonides.
2010
Abstract Hf5Sb3 can be prepared by arc-melting of hafnium and previously synthesized HfSb2. It crystallizes like the high-temperature modification of Zr5Sb3 in the Y5Bi3 structure type, space group Pnma, Z=4, a=740.75(9) pm, b=871.8(1) pm, c=1073.6(1) pm, V=693.3(1) 106pm3. An antimonide analogous to the low-temperature form of Zr5Sb3 was not obtained during our investigations. In the structure of Hf5Sb3, the Hf atoms form a three-dimensional network with numerous short Hf–Hf contacts, including the Sb atoms in severely distorted two- and three-capped trigonal prismatic voids. Calculations of the electronic structure, performed with the extended Huckel approximation as well as the TB-LMTO-A…
X-ray crystal structure and electronic properties of chlorobis(mepirizole)copper(II) tetrafluoroborate (mepirizole = 4-methoxy-2-(5-methoxy-3-methyl-…
1997
Abstract The crystal structure of [Cu(mep)2Cl](BF4)[mep = 4-methoxy-2-(5-methoxy-3-methyl-1H-pyrazol-1-yl)-6-methylpyrimidine] has been determined by X-ray diffraction. The crystal structure is built up of [Cu(mep)2Cl]+ cations and BF4− anions. The structure of the cation involves a five-coordinated CuN4Cl chromophore, with a stereochemistry near to a compressed trigonal bypyramid (TBP) but with a significant degree of distortion towards the square pyramidal (SP) topology. The EPR spectrum is indicative of a mixed dz2/dx2 − y2 ground state for the copper(II) ions, in agreement with the structural data.
Syntheses, crystal structures and magnetic properties of chromato-, sulfato-, and oxalato-bridged dinuclear copper(II) complexes
2000
Abstract Four dinuclear copper(II) complexes of formula [Cu2(bpca)2(H2O)3(CrO4)]·H2O (1), [Cu2(bpca)2(H2O)3(SO4)]·H2O (2), [Cu2(bpca)2(H2O)2(C2O4)]·2H2O (3), and [Cu2(bpca)2(C2O4)] (4) [bpca=bis(2-pyridylcarbonyl)amide anion] have been synthesized and their magnetic behavior has been investigated as a function of temperature. The structures of 1–3 have been determined by single-crystal X-ray diffraction, whereas the structure of 4 was already known. The structures of this family of complexes are made up of neutral chromateO1,O1′ (1), sulfateO1,O1′ (2) and oxalateO1,O2:O1′,O2′-bridged (3 and 4) dinuclear copper(II) units. The two copper atoms within the dinuclear unit of the isomorphous c…
Synthesis, structure, spectral characterization and DNA binding affinity of new water soluble trinuclear copper(II) complexes with partial cubane Cu3…
2015
Two new water soluble trinuclear copper(II) complexes, [Na 6 (H 3 O) 4 ][Cu 3 (cbal) 3 (μ 3 -OH)(H 2 O) 3 ] 4 (ClO 4 ) 6 ·3H 2 O ( 1 ) and [K(H 2 O) 2 ][Cu 3 (cbal) 3 (μ 3 -OH)(H 2 O)]·3.75H 2 O ( 2 ) have been synthesized in good yield via the reaction of an unsymmetrical amino dicarboxylic ligand, N-(2-carboxybenzomethyl)-β-alanine (H 2 cbal), Cu(ClO 4 ) 2 ·6H 2 O and NaOH/K 2 CO 3 in methanol at room temperature. Complexes 1 and 2 have been characterized by elemental analysis, room temperature magnetic susceptibility measurements, FTIR, UV–Vis, mass spectrometry and single crystal X-ray crystallography. Both complexes contain a partial cubane [Cu 3 O 4 ] core consisting of the trinuclear…