Publications by authors named "Hans Reuter"

The title compound, [Sn(CH)(NCS)], which crystallizes with one and a half mol-ecules in the asymmetric unit, represents a new structure type for inter-molecular sulfur⋯tin inter-actions, which is characterized by an anti-parallel () arrangement of the dipole moments of the individual mol-ecules. In the resulting zigzag chains, the mol-ecules are related to each other by mirror planes () and twofold rotation axes (2), both perpendicular to the propagation plane, while translation is realized a glide plane in direction of the crystallographic axis, a combination of symmetry elements unique in the structural chemistry of diorganotin(IV) dihalides and pseudohalides, Sn with = Hal or NCS. Its characteristics are subsumed in the term 2 for this kind of inter-molecular association pattern.

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In the title compound, di-phenyl-tin(IV) diiso-thio-cyanate, [Sn(NCS)(CH)] or PhSn(NCS), comparatively long tin-nitro-gen and short tin-sulfur bonds prove that the ambidentate iso-thio-cyanate ion acts as a bridge between two neighboring, octa-hedrally coordinated tin atoms. As a result, the mol-ecules lose their individuality in favor of a layered coordination polymer that represents a new type of mol-ecular inter-actions in the structural chemistry of diorganotin(IV) dihalides/pseudohalides. The tin atom is located on a center of inversion.

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In the hydrated title complex, [Fe(dpa)(N)]·HO (dpa is 2,2'-di-pyridyl-amine, CHN), the Fe ion is coordinated in a distorted octa-hedral manner by two neutral, chelating dpa ligands and two anionic, monodentate azide (N ) ions in a -configuration. Distortion results from different Fe-N bond lengths [2.1397 (13)-2.

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Developing new anticancer agents can be useful, with the ability to diagnose and treat cancer worldwide. Previously, we focused on examining the effects of nonoxidovanadium(IV) complexes on insulin mimetic and cytotoxicity activity. In this study, in addition to the cytotoxic activity, we evaluated their bioimaging properties.

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In the title compound, bis-[aqua-(2,2'-bi-pyridine)-fluorido-tin(II)] hexa-fluorido-tin(IV), [SnF(CHN)(HO)][SnF], an ionic mixed-valent tin(II)-tin(IV) compound, the bivalent tin atom is the center atom of the cation and the tetra-valent tin atom is the center atom of the anion. With respect to the first coordination sphere, the cation is monomeric, with the tin(II) atom having a fourfold seesaw coordination with a fluorine atom in an equatorial position, a water mol-ecule in an axial position and the two nitro-gen atoms of the chelating 2,2'-bi-pyridine ligand in the remaining axial and equatorial positions. The bond lengths and angles of this hypervalent first coordination sphere are described by 2-2 and 3-4 bonds, respectively, all of which are based on the orthogonal 5 orbitals of the tin atom.

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In this report, four new Ni(II)-unsymmetrical salen complexes, [NiL], were prepared by refluxing Ni(Ac)·4HO with unsymmetrical salen ligands, HL. All of the synthesized ligands and complexes were characterized by various physicochemical methods. Also, the solid-state structures of [NiL], [NiL], and [NiL] were defined through single-crystal X-ray diffraction methods.

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Di-μ-hydroxido-bis-[di-bromido-(di-methyl-formamide-κ)ethyl-tin(IV)], [SnBr(CH)(OH)(CHNO)], was prepared from ethyl-tin(IV) bromide and ,-di-methyl-formamide (DMF) in air. The crystal structure exhibits the typical structural features of dimeric Lewis-base-stabilized monoorganotin(IV)-dihalide-hydroxides, SnHal(OH), two octa-hedrally coordinated Sn atoms are linked together two bridging hydroxide groups, resulting in a centrosymmetric four-membered rhomboid-like Sn-OH ring with acute angles at the Sn atom, obtuse angles at the O atoms and two different tin-oxygen bond lengths. With the shorter bond to the ethyl group, this observation underlines once more the so-called effect in monoorganotin(IV) com-pounds with octa-hedrally coordinated Sn atoms.

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A series of mononuclear non-oxido vanadium(IV) complexes, [V(L)] (), featuring tridentate bi-negative ONS chelating S-alkyl/aryl-substituted dithiocarbazate ligands HL, are reported. All the synthesized non-oxido V compounds are characterized by elemental analysis, spectroscopy (IR, UV-vis, and EPR), ESI-MS, as well as electrochemical techniques (cyclic voltammetry). Single-crystal X-ray diffraction studies of - reveal that the mononuclear non-oxido V complexes show distorted octahedral ( and ) or trigonal prismatic () arrangement around the non-oxido V center.

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The structure of the dimeric title compound, [Sn(CH)Cl(OH)], was redetermined at 100 K by use of an area detector to provide new data to improve the structural parameters for detailed analysis. Noteworthy is the folding of the central, non-symmetric, four-membered [SnO] ring [dihedral angle about the O⋯O axis = 1.09 (3)°], as well as the elongation of the Sn-Cl bonds [mean value = 2.

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A temperature-controlled facile synthesis of multisubstituted 4-alkynyl/ 4-alkenyl coumarins with a metal salt cascade approach is reported. HO serves both as a nucleophile and hydrogen source. The presence of metal salt facilitates the reduction of alkyne.

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The crystal structure of di--butyl-hydroxido-iodido-tin(IV), [Sn(CH)I(OH)] or BuSn(OH)I, consists of dimeric, centrosymmetric mol-ecules exhibiting the typical structural features of diorganotin(IV)-hydroxide-halides, Sn(OH). Two trigonal-bipyramidally coordinated tin(IV) atoms are bridged two hydroxyl groups, resulting in a planar, four-membered {Sn-O} ring of rhombic shape, with acute angles at tin, obtuse angles at oxygen and two different Sn-O distances depending whether the oxygen atom adopts an axial or equatorial position at the tin(IV) atom. In contrast to its fluorine, chlorine and bromine homologues, no hydrogen bonds between the OH group and the halide atom exist, confining the inter-molecular inter-actions to van der Waals forces.

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Single crystals of tribarium hexa-hydroxidostannate(IV) bis-[selenate(VI)] trihydrate, BaHOSeSn or Ba[Sn(OH)][SeO]·3HO, prepared from solid BaSnO and aqueous Na[SeO] solutions have hexa-gonal (6) symmetry. The structure consists of four different primary building units: a hexa-hydroxidostannate(IV) ion, two different selenate(VI) ions, all three of point group symmetry , and a mono-capped {BaO}-square anti-prism of point group symmetry . The secondary building units result from three of the barium coordination polyhedra linked together common edges.

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Article Synopsis
  • The compound 3-phenyltetrahydropyrimido[4,5-c]pyridazine 2'-deoxyribonucleoside exists in two distinct conformations in its crystalline state, each with different sugar pucker configurations.
  • Conformers 1a and 1b both maintain similar anti conformations around their N-glycosylic bonds and are stabilized by intermolecular hydrogen bonds, with Hirshfeld surface analysis confirming their bonding patterns.
  • The nucleoside effectively pairs with dA, showing stability comparable to the canonical dA-dT pair, and its duplex stability is further enhanced by interactions with a dA analogue.
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Three ONNO donor tetradentate diamino bis(phenolato) "salan" ligands, N, N'-dimethyl-N, N'-bis-(5-chloro-2-hydroxy-3-methyl-benzyl)-1,2-diaminoethane (HL), N, N'-dimethyl-N, N'-bis-(5-chloro-2-hydroxy-3-isopropyl-6-methyl-benzyl)-1,2-diamino-ethane (HL) and N, N'-bis-(5-chloro-2-hydroxy-3-isopropyl-6-methyl-benzyl)-1,2-diaminocyclohexane (HL) have been synthesized by following Mannich condensation reaction. Reaction of these ligands with their corresponding vanadium metal precursors gave one oxidomethoxidovanadium(V) [VOL(OCH)] (1) and two monooxido-bridged divanadium (V, V) complexes [VOL](μ-O) (2-3). The complexes were characterized by IR, UV-vis, NMR and ESI mass spectrometry.

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The Jahn-Teller (JT) theorem constitutes one of the most fundamental concepts in chemistry. In transition-element chemistry, the 3d and 3d configurations in octahedral complexes are particularly illustrative, where a distortion in local geometry is associated with a reduction of the electronic energy. However, there has been a lasting debate about the fact that the octahedra are found to exclusively elongate.

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In the solid-state structures of -poly[[di-chlorido-tin(II)]-μ-(4-methyl-pyridine -oxide)-κ :], [SnCl(CHNO)] , , and di-chlorido-bis-(4-methyl-pyridine -oxide-κ)tin(II), [SnCl(CHNO)], , the bivalent tin atoms reveal a seesaw coordination with both chlorine atoms in equatorial and the Lewis base mol-ecules in axial positions. While the Sn-Cl distances are almost identical, the Sn-O distances vary significantly as a result of the different bonding modes (μ for , μ for ) of the 4-methyl-pyridin--oxide mol-ecules, giving rise to a one-dimensional coordination polymer for the 1:1 adduct, , and a mol-ecular structure for the 1:2 adduct, . The different coordination modes also influence the bonding parameters within the almost planar ligand mol-ecules, mostly expressed in N-O-bond lengthening and endocyclic bond-angle widening at the nitro-gen atoms.

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An efficient copper-catalyzed cyclization cascade approach towards highly functionalized methylene 4-chromanol and aurone derivatives has been developed from reactions of ynols via 6-exo-dig and 5-exo-dig cyclization respectively. The catalysis involves alkyne activation via diorgano-diselenides and also their regioselective incorporation into the methylene 4-chromanol and aurone derivative core and is an open-air transformation.

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An efficient two-component copper-catalyzed cyclization cascade approach toward highly functionalized indolizinone heterocycles has been developed from reactions of pyridine-, isoquinoline-, and quinoline ynones, via 5-- cyclization. The catalysis involves the activation by diorgano diselenide and diorgano disulfide and also their incorporation into the indolizinone core. In addition, the obtained substituted indolizinones were readily transformed into 1-(organochalcogenyl)indolizin-2-ols, which are important building blocks in organic synthesis.

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Two new dimeric Zn(II) ([{ZnL(DMSO)}]·DMSO (1), [{ZnLCl}] (2)) and a novel tetrameric Zn(II) complex ([(ZnL)(μ-OAc)(μ-O)] (3)), where HL = 4-(p-methoxyphenyl) thiosemicarbazone of o-hydroxynapthaldehyde, HL = 4-(p-methoxyphenyl)thiosemicarbazone of benzoyl pyridine and HL = 4-(p-chlorophenyl)thiosemicarbazone of o-vanillin are reported. Ligands and their complexes were characterized by spectroscopic and single crystal X-ray diffraction techniques. In addition, the complexes exhibited good binding affinity towards HSA (10 M), which is supported by their ability to quench the tryptophan fluorescence emission spectra of HSA.

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A series of eight hexacoordinated mixed-ligand oxidovanadium(IV) complexes [VO(L)(L)] (1-8), where L = L - L are four differently substituted ONO donor aroylhydrazone ligands and L are N,N-donor bases like 2,2'-bipyridine (bipy) (1, 3, 5 and 7) and 1,10-phenanthroline (phen) (2, 4, 6 and 8), have been reported. All synthesized complexes have been characterized by various physicochemical techniques and molecular structures of 1 and 6 were determined by X-ray crystallography. With a view to evaluate the biological activity of the VO species, the behavior of the systems VO/L, VO/L/bipy and VO/L/phen was studied as a function of pH in a mixture of HO/DMSO 50/50 (v/v).

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We report the synthesis, crystal structure, and basic physical properties of Ag8PtO6, which represents the first silver platinum ternary oxide. The crystalline compound was obtained from appropriate mixtures of the binary constituents under alkaline conditions at high oxygen pressure, while applying relatively mild thermal conditions (573 K). Ag8PtO6 crystallizes in a new crystal structure in the triclinic system (P1[combining macron]).

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The lipophilization of β-d-riboguanosine (1) with various symmetric as well as asymmetric ketones is described (→3a-3f). The formation of the corresponding O-2',3'-ketals is accompanied by the appearance of various fluorescent by-products which were isolated chromatographically as mixtures and tentatively analyzed by ESI-MS spectrometry. The mainly formed guanosine nucleolipids were isolated and characterized by elemental analyses, H-, C-NMR and UV spectroscopy.

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The crystal structure redetermination of SrPdO (distrontium palladium trioxide) was carried out using high-quality single-crystal X-ray data. The SrPdO structure has been described previously in at least three reports [Wasel-Nielen & Hoppe (1970 ▸). .

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2-Chloro-2'-deoxyadenosine (cladribine, 1) was acylated with valproic acid (2) under various reaction conditions yielding 2-chloro-2'-deoxy-3',5'-O-divalproyladenosine (3) as well as the 3'-O- and 5'-O-monovalproylated derivatives, 2-chloro-2'-deoxy-3'-O-valproyladenosine (4) and 2-chloro-2'-deoxy-5'-O-valproyladenosine (5), as new co-drugs. In addition, 6-azauridine-2',3'-O-(ethyl levulinate) (8) was valproylated at the 5'-OH group (→9). All products were characterized by H- and C-NMR spectroscopy and ESI mass spectrometry.

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The synthesis of ethoxido-bridged dinuclear oxidovanadium(IV) complexes of the general formula (HNEt)[(VOL)(μ-OEt)] (1-3) with the azo dyes 2-(2'-carboxy-5'-X-phenylazo)-4-methylphenol (HL, X = H; HL, X = NO) and 2-(2'-carboxy-5'-Br-phenylazo)-2-naphthol (HL) as ligands is reported. The ligands differ in the substituents at the phenyl ring to probe their influence on the redox behavior, biological activity, and magnetochemistry of the complexes, for which the results are presented and discussed. All synthesized ligands and vanadium(IV) complexes have been characterized by various physicochemical techniques, namely, elemental analysis, electrospray ionization mass spectrometry, spectroscopic methods (UV/vis and IR), and cyclic voltammetry.

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