Search results for "Structure Elucidation"

Two new supramolecular architectures of singly phenoxo-bridged copper(II) and doubly phenoxo-bridged manganese(II) complexes derived from an unusual …

2009

International audience; Two new coordination complexes {[(L)Cu2('-L)(NO3)(CH3OH)0.3(H2O)0.7]·NO3}[Cu(L)(NO3)(CH3OH)] (1) and [Mn2(-L)2(H2O)(1-N3)2(CH3OH)] (2) derived from (E)-N-(2-hydroxy-3-methoxybenzylidene)acetohydrazide [LH] have been synthesized. The new potentially tetradentate ONOO donor hydrazone ligand [LH] has shown considerable metal ion selective phenoxo bridging in 1 and 2. It has coordinated copper(II) ions in its tridentate as well as in tetradentate fashion whereas for manganese(II) ions it solely showed its tetradentate character. In 1 the two adjacent pentacoordinate copper(II) centers are connected by a rare single phenoxo linkage of the hydrazone ligand whereas 2 is a d…

Structural Characterisation of Complex Layered Double Hydroxides and TGA-GC-MS Study on Thermal Response and Carbonate Contamination in Nitrate- and …

2015

Layered double hydroxides (LDHs) are versatile materials used for intercalating bioactive molecules in the fields of pharmaceuticals, nutraceuticals and cosmetics, with the purpose of protecting them from degradation, enhancing their water solubility to increase bioavailability and improving their pharmacokinetic properties and formulation stability. Moreover, LDHs are used in various technological applications to improve stability and processability. The crystal chemistry of hydrotalcite-like compounds was investigated by X-ray powder diffraction (XRPD), automated electron diffraction tomography (ADT) and thermogravimetric analysis (TGA)-GC-MS to shed light on the mechanisms involved in io…

Novel inhibitors of mitochondrial respiratory chain: endoperoxides from the marine tunicate Stolonica socialis.

2001

The Mediterranean tunicate Stolonica socialis contains a new class of powerful cytotoxic acetogenins, generically named stolonoxides. In this paper, which also details the isolation and chemical characterization of a minor component (3a) of the tunicate extract, we report the potent inhibitory activity (IC(50) < 1 microM) of stolonoxides (1a and 3a) on mitochondrial electron transfer. The compounds affect specifically the functionality of complex II (succinate:ubiquinone oxidoreductase) and complex III (ubiquinol:cytochrome C oxidoreductase) in mammalian cells, thereby causing a rapid collapse of the whole energetic metabolism. This result, which differs from the properties of similar known…

Single-Ion Magnetic Behavior in CoII-CoIII Mixed-Valence Dinuclear and Pseudodinuclear Complexes

2017

Two CoII–CoIII mixed-valence complexes of molecularformulas [Co2(H2L)2(H2O)2][Co2(H2L)2(H2O)(m-phth)]·8(H2O) {1;H2L2–= 2-[(2-hydroxy-3-methoxybenzylidene)amino]-2-(hydroxymethyl)propane-1,3-diolato, m-phth = 1,3-benzene-dicarboxylate} and [Co4(H2L)4(H2O)2(ppda)]·2(dmf)·3.2(H2O) {2;ppda = 1,4-phenylenediacrylate; dmf = N,N-dimethyl-formamide} were synthesized and characterized by single-crys-tal X-ray diffraction and magnetic studies at low temperature.The structural determination reveals that 1 is composed of di-nuclear ion pairs, namely, a cationic [Co2(H2L)2(H2O)2]+(1+) andan anionic [Co2(H2L)2(H2O)(m-phth)]–(1–) unit. In each of these ions, the CoIIand CoIIIcenters present distorted octa…

Tanzawaic acids I-L: Four new polyketides from Penicillium sp. IBWF104-06.

2014

Four new polyketides have been identified in culture filtrates of the fungal strain Penicillium sp. IBWF104-06 isolated from a soil sample. They are structurally based on the same trans-decalinpentanoic acid skeleton as tanzawaic acids A–H. One of the new compounds was found to inhibit the conidial germination in the rice blast fungus Magnaporthe oryzae at concentrations of 25 μg/mL.

SF002-96-1, a new drimane sesquiterpene lactone from an Aspergillus species, inhibits survivin expression

2013

Survivin, a member of the IAP (inhibitor of apoptosis) gene family, is overexpressed in virtually all human cancers and is functionally involved in the inhibition of apoptosis, regulation of cell proliferation, metastasis and resistance to therapy. Because of its upregulation in malignancy, survivin has currently attracting considerable interest as a new target for anticancer therapy. In a screening of approximately 200 strains of imperfect fungi for the production of inhibitors of survivin promoter activity, a new drimane sesquiterpene lactone, SF002-96-1, was isolated from fermentations of an Aspergillus species. The compound inhibited survivin promoter activity in transiently transfected…

A new member of the fusaricidin family – structure elucidation and synthesis of fusaricidin E

2017

Two hitherto unknown fusaricidins were obtained from fermentation broths of three Paenibacillus strains. After structure elucidation based on tandem mass spectrometry and NMR spectroscopy, fusaricidin E was synthesized to confirm the structure and the suggested stereochemistry. The synthesis was based on a new strategy which includes an efficient access to the 15-guanidino-3-hydroxypentadecanoyl (GHPD) side chain from erucamide.

Halogen Bonds in Square Planar 2,5-Dihalopyridine-Copper(II) Bromide Complexes

2018

Comment on "Crystallographic Snapshot of an Arrested Intermediate in the Biomimetic Activation of CO2"

2015

Out of focus: A recent Communication published in this journal describes the synthesis of [nBu4N]HCO3. The authors performed a single-crystal X-ray study that revealed a putative species described as an incipient hydroxide ion engaging in a long, and presumably weak, interaction with CO2. Our recent exploration of the coordination chemistry of CO2 with small ions leads us to believe that such an exceptional bonding situation is unlikely. Instead, we argue that the crystal structure is that of [nBu4N]O2CCH3 and therefore not representative of the bulk powder from the synthesis. peerReviewed

Comment on “Crystallographic Snapshot of an Arrested Intermediate in the Biomimetic Activation of CO2”

2015

Out of focus: A recent Communication published in this journal describes the synthesis of [nBu4 N]HCO3 . The authors performed a single-crystal X-ray study that revealed a putative species described as an incipient hydroxide ion engaging in a long, and presumably weak, interaction with CO2 . Our recent exploration of the coordination chemistry of CO2 with small ions leads us to believe that such an exceptional bonding situation is unlikely. Instead, we argue that the crystal structure is that of [nBu4 N]O2 CCH3 and therefore not representative of the bulk powder from the synthesis.