Search results for "Molecular geometry"
showing 10 items of 601 documents
Synthesis, crystal structure and properties of two acetazolamide (5-acetamido-1,3,4-thiadiazole-2-sulfonamide) complexes: bis(5-acetamidato- 1,3,4-th…
1992
Abstract The diverse coordination chemistry exhibited by acetazolamide (H2acm), a potent inhibitor of the carbonic anhydrase metalloenzyme, is highlighted in two new copper(II) complexes of this ligand: [Cu(Hacm)2(en)2] (I) and [Cu(Hacm)2(tn)2] (II). The synthesis, crystal structure and spectroscopic properties of both compounds are reported in this paper. The structures of both compounds consist of discrete units of [Cu(Hacm)2(en)2] (I) and [Cu(Hacm)2(tn)2] (II), respectively, interacting through van der Waals contacts and hydrogen bonds only. Hacm, however, binds differently in each compound. In both cases, the Cu(II) ions, lying on the symmetry centers, show an elongated octahedral geome…
Alkyl Complexes of Rare-Earth Metals That Contain a Furyl-Functionalized Cyclopentadienyl Ligand: Alkyl Cation Formation and Unexpected Ring-Opening…
2003
Rare-earth metal complexes of the type [Ln{η5:η1-C5Me4SiMe2(C4H3O-2)}(CH2SiMe3)2(THF)] (Ln = Y, Lu) were prepared by σ-bond metathesis of [Ln(CH2SiMe3)3(THF)2] with the 2-furyl-functionalized tetramethylcyclopentadiene (C5Me4H)SiMe2(C4H3O-2) and isolated as colorless crystals. Single-crystal X-ray structure analysis of the lutetium complex confirmed the coordination of the furyl group and THF to give a molecule of trigonal bipyramidal geometry with the oxygen donor atoms in the apical positions. The lability of the oxygen donor atoms results in fluxional behavior. Reaction with triphenylborane in THF gave thermally robust mono(alkyl) cations [Ln{η5:η1-C5Me4SiMe2(C4H3O-2)}(CH2SiMe3)(THF)n]+.…
Studies on the antitumor activity of complexes of R2Sn(IV) with penicillamine enantiomers and with 3-thio-propanoic acid, and correlation with struct…
1990
Abstract The activity of diorganotin(IV) derivatives, with SnS bonds, against murine leukemia P-388, has been investigated. The water-soluble penicillamine (PenH2) complexes, Me2Sn(D-Pen), Me2Sn(L-Pen), Me2Sn(D-PenH)2 and Me2Sn(L-PenH)2, are essentially inactive, and do not show any dependence of the antitumor activity from the configuration about the chiral centre. The complexes with 3-thiopropanoic acid (H2Tpr), R2Sn(Tpr), are active for REt and Ph, in line with the general behaviour of R2Sn(IV) derivatives. The nature of the organotins in the vehicle of administration is investigated by 119Sn Mossbauer spectroscopy. The structures of solid state polymers, occurring in suspensions, are …
Strong protective action of Copper(II) N-substituted sulfonamide complexes against reactive oxygen species.
2004
Copper(II) complexes of N -benzothiazolsulfonamides, [Cu( N -2-(5,6-dimethylbenzothiazole)toluenesulfonamidate) 2 (dmso) 2 ] ( 1 ), [Cu( N -2-(6-chlorobenzothiazole)benzenesulfonamidate) 2 (dmso) 2 ] ( 2 ) and [Cu( N -2-(6-chlorobenzothiazole)toluenesulfonamidate) 2 (dmso) 2 ] ( 3 ) with interesting protective properties against superoxide radicals have been prepared. The compounds have been characterized by X-ray diffraction and their chemical properties have been studied by spectroscopic methods. The crystal structure of 1 shows that the copper(II) is surrounded by two benzothiazole N atoms from the sulfonamide ligands and two O atoms from the dimethylsulfoxide molecules in a square plana…
Tuning of interfacial charge transport in polyporphine/phthalocyanine heterojunctions by molecular geometry control for an efficient gas sensor
2022
Abstract Owing to high interfacial conductivity, organic heterostructures hold great promises to augment the electrical performances of electronic devices. In this endeavor, the present work reports fabrication of novel polyporphine/phthalocyanine heterostructures and investigates the modulation of charge transport induced by structural change of polyporphine and its implication on ammonia sensing properties. Polyporphines materials are electrosynthesized by oxidation of zinc(II) porphine monomer that corresponds to the fully unsubstituted porphyrin. At less-positive anodic potential, low conducting meso,meso-singly-linked type-1 polymer (pZnP-1) is formed in which a monomer unit stays orth…
ChemInform Abstract: Preparation and Structural Characterization of (Me3SiNSN)2Se, a New Synthon for Sulfur-Selenium Nitrides.
2010
The reaction of (Me(3)SiN)(2)S with SeCl(2) (2:1 ratio) in CH(2)Cl(2) at -70 degrees C provides a route to the novel mixed selenium-sulfur-nitrogen compound (Me(3)SiNSN)(2)Se (1). Crystals of 1 are monoclinic and belong the space group P2(1)/c, with a = 7.236(1) A, b = 19.260(4) A, c = 11.436(2) A, beta = 92.05(3) degrees, V = 1592.7(5) A(3), Z = 4, and T = -155(2) degrees C. The NSNSeNSN chain in 1 consists of Se-N single bonds (1.844(3) A) and S=N double bonds (1.521(3)-1.548(3) A) with syn and anti geometry at the N=S=N units. The N-Se-N bond angle is 91.8(1) degrees. The EI mass spectrum shows a molecular ion with good agreement between the observed and calculated isotopic distributions…
Mn(II) complexes with sulfonamides as ligands.
2012
Abstract Sulfonamides derived from 8-aminoquinoline react with Mn(II) and Mn(III) salts to form Mn(II) complexes; the Mn(III) species are reduced to the divalent state in the presence of 1,10 phenanthroline and bipyridine. Their molecular structure, determined by single crystal X‐ray diffraction, show that all the complexes present a distorted octahedral geometry, in which the deprotonated sulfonamide acts as a bidentate ligand. UV–visible spectroscopy and changes in the melting temperature (Tm) of calf thymus DNA show a strong interaction of these complexes with DNA. The significant hypochromicity of the charge transfer transition at 370 nm without an appreciable change in wavelength and t…
1H,13C and17O NMR spectroscopic study of four bicyclo [3.1.1]heptenes (derivatives of α-pinene) and four bicyclo[3.1.1]heptanes (derivatives of β-pin…
1992
Four derivatives of 2, 6, 6-trimethylbicyclo[3.1.1]hept-2-ene (α-pinene) and four derivatives of 2-methylene-6, 6-dimethylbicyclo[3.1.1]heptane (β-pinene) were synthesized and their 1H, 13C and 17O NMR spectra were measured, analysed and assigned. The 1H NMR spectral parameters were obtained by computer-aided analyses of the very complex multi-spin, second-order spectra. Some of the 13C NMR chemical shift assignments of these compounds reported in the literature should be changed, based on these accurate 1H NMR spectral analyses and carbon-proton chemical shift correlated spectra (COSY). The new assignments are supported by the 1J(C, H) values, which show a strong dependence on the bond ang…
Synthesis and Structures of Two Triorganotin(IV) Polymers R3Sn{O2CC6H4[N=C(H)}{C(CH3)CH(CH3)-3-OH]-p} n (R = Me and Ph) Containing a 4-[(2Z)-(3-Hydro…
2009
Two new polymeric triorganotin(IV) complexes R3Sn{O2CC6H4[N=C(H)}{C(CH3)CH(CH3)-3-OH]-p} n ([Me3Sn(LH)] n : 1) and ([Ph3Sn(LH)] n : 2) containing a 4-[(2Z)-(3-hydroxy-1-methyl-2-butenylidene)amino]benzoate (LH) framework were prepared. Both compounds have been characterized by 1H, 13C, 119Sn NMR, IR and 119Sn Mossbauer spectroscopic techniques in combination with elemental analyses. The crystal structures of complexes 1 and 2 reveal that they exist as polymeric zig-zag chains in which the LH-bridged Sn-atoms adopt a trans-R3SnO2 trigonal bipyramidal configuration with R groups in the equatorial positions and the axial sites occupied by an oxygen atom from the carboxylate ligand and the alco…
Unified Thermodynamic Modeling of Polymer Solutions: Polyelectrolytes, Proteins, and Chain Molecules
2013
The thermodynamic description of the systems specified in the title requires in general dissimilar theories. This contribution presents an approach that is capable of modeling all of them with a maximum of three adjustable parameters. The Ansatz starts from the Flory–Huggins theory and extends it in a 2-fold manner: The number of segments assigned to the solvent is no longer one but treated as an adjustable parameter to account for the differences in the molecular geometries and in the free volumes of the components. Furthermore, the modeling allows for effects resulting from ternary contacts of the solvent/polymer/polymer type. Examination of the acquired thermodynamic expressions by means…