Timothy R. Wagner

Evaluation on the role of terminal N -substitution in 6-methoxy-2-oxo-1,2-dihydroquinoline-3-carbaldehyde thiosemicarbazones on the biological properties of new water-soluble nickel( ii ) complexes

Five new nickel(II) complexes of 6-methoxy-2-oxo-1,2-dihydroquinoline-3-carbaldehyde 4N-substituted thiosemicarbazones with the general formula {[Ni(HL)2](NO3)2·4H2O} have been synthesised in order to ascertain the biological properties due to the change in substitution at terminal nitrogen of the thiosemicarbazones. The structure of one of the complexes was established by single-crystal X-ray diffraction analysis. DNA/protein interactions of the complexes have been examined by photophysical studies which revealed that all the complexes can bind with calf thymus DNA via intercalation and the complexes bind to bovine serum albumin more strongly. Antioxidant studies showed that the Ni(II) complexes have significant antioxidant activity against 2-2′-diphenyl-1-picrylhydrazyl radical and 2,2′-azino-3-ethylbenzthiazoline-6-sulfonic acid diammonium salt cation radical. The in vitro cytotoxicity of all the complexes against the A549 cell line was assayed; this showed highest cytotoxic activity for the complex containing phenyl substituted thiosemicarbazone – higher than found for cisplatin.

The synthesis and characterization of Ni, Pd and Pt maleonitriledithiolate complexes: X-ray crystal structures of the isomorphous Ni, Pd and Pt (Ph2PCH2CH2PPh2)M(maleonitriledithiolate) congeners

Abstract The synthesis of a series of maleonitriledithiolate complexes of nickel, palladium and platinum phosphines having the formulae (dppe)M(mnt) and (Ph3P)2M(mnt) (where dppe = Ph2PCH2CH2PPh2, mnt = 1,2-dicyanoethene-1,2-dithiolate and M = Ni, Pd or Pt) from the reaction of Na2(mnt) and the appropriate (phosphine) MCl2 is reported. These complexes were characterized by a combination of mass spectrometry, IR, UV-Visible and 1H. 13C and 31P NMR spectroscopy. In addition, characterization of the title complexes by single crystal X-ray diffraction of all three congeners revealed them to be isomorphous. Analysis of the diffraction data reveals that the metal centers are all square planar, that the planar mnt ligands are tilted slightly away fro the metal square planes, and that the mnt ligand is best described as a dithiolate rather than a dithione.

Synthesis and characterization of color variants of nitrogen- and fluorine-substituted TiO2

Reaction pathways to nitrogen- and fluorine-doped TiO2 have been investigated and the compositions analyzed by neutron powder diffraction, nitrogen analyses and titrations of Ti3+. The reported formation of TiNF under pyrolysis of (NH4)2TiF6 in NH3 could not be reproduced when H2O was carefully excluded. If special precautions are not taken to exclude H2O, a product of the previously reported olive-green appearance is obtained; TiN0.05O1.89F0.06, in which 1% of Ti is trivalent. The prolonged hydrolysis and ammonolysis leading to this product proceeds via the intermediates (NH4)1−xTiOF3−x, which adopts the hexagonal tungsten–bronze structure, and/or TiOF2. The latter is therefore suggested as a convenient starting material for doped anatase pigments. Reflectance measurements couple the green color with valence to conduction band excitations (Eg = 2.3 eV) and intraband transitions involving Ti3+. The green phase can be converted to a brilliant yellow in the presence of water vapor at 400–600 °C, which further hydrolyzes the fluoride and oxidizes the titanium, yielding TiN0.04O1.92F0.04 in a particular case. The yellow color and band gap (Eg = 2.4 eV) may be promising for applications as a pigment or photocatalyst. Neutron powder diffraction characterizations and UV–Visible reflectance measurements indicate homogenous doping throughout the bulk. The combined results suggest that the green and yellow phases are part of a homogeneity range adjacent to TiO2, in which the band gap narrowing results largely from nitrogen for oxygen subsitution and the green color is linked to formation of Ti3+ defects.

Cu(I)-catalyzed Formation of D-Mannofuranosyl 1,4-Disubstituted 1,2,3-Triazolecarbohybrids

2,3:5,6-Di-O-isopropylidene-D-mannofuranose has been exploited as a platform for the synthesis of new 1,2,3-triazolecarbohybrids. Placement of an azide group at C-1 (and C-6) of the carbohydrate allows for reaction with various alkynes in the presence of a Cu(I) catalyst to generate 1,4-disubstituted triazoles regiospecifically. The use of sugar-derived alkynes leads to 1,2,3-triazole-linked di- and trisaccharide carbohybrid analogs with retention of the β-D-manno configuration.

Doubled-cubic Ca2NF.

Crystals of dicalcium nitride fluoride, Ca2NF, grown from the melt have been characterized by X-ray diffraction and were found to have a cubic (Fd-3m) structure. Owing to ordering of N and F atoms along all three cell axes, the cell edge is doubled relative to the rocksalt-type structure reported previously. Residual electron density at an interstitial tetrahedral site was refined as a Frenkel defect of F atoms, giving a final composition of Ca2N(F0.913)oct(F0.087)tet.

Crystal structure of methyl 1,2,3,4-tetra-O-acetyl-β-d-glucopyranuronate

Abstract The identity of the crystalline product formed by the acetylation of a mixture of methyl α- and β- d -glucopyranuronates has been confirmed as being methyl 1,2,3,4-tetra- O -acetyl-β- d -glucopyranuronate ( 3 ), which agrees with the assignment from 1 H NMR. The absolute configuration of compound 3 was assigned to agree with the known chirality of the precursor sugar, d -glucono-6,3-lactone.

Crystal structure of 1,2;5,6-di-O-isopropylidene-3-O-(phenylacetyl)-D-glucofuranose

The synthesis and X-ray crystal structure of 1,2;5,6-di-O-isopropylidene-3-O-(phenylacetyl)-D-glucofuranose is reported. It crystallizes in the orthorhombic system with space group P212121 (No. 19); a = 9.9313(12) Å, b = 10.0657(12) Å, c = 20.343(2) Å, and Z = 4. The solid state structure is discussed in terms of the use of the title compound for further chemistry.

1,2‐Bis­(di­tolyl­phosphino)­ethane

In the solid state, the title compound, 1,2-{(p-CH3–C6H4)2P}2C2H4 or C30H32P2, exhibits trans geometry. There is an inversion center at the mid-point of the central C—C bond.

Solution and solid-state structure of 2,6-anhydro-1,1-bis(ethylsulfonyl)-1-deoxy-d-talitol

Abstract d -Galactose diethyl dithioacetal can be oxidized with m -chloroperoxybenzoic acid to produce the previously described highly crystalline bis(ethylsulfone), the structure of which has now been confirmed by nuclear magnetic resonance spectroscopy and X-ray crystallography.