Search results for "STRUCTURE ELUCIDATION"

Electrical conductivity and strong luminescence in copper Iodide double chains with isonicotinato derivatives

2015

Direct reactions between CuI and isonicotinic acid (HIN) or the corresponding esters, ethyl isonicotinate (EtIN) or methyl isonicotinate (MeIN), give rise to the formation of the coordination polymers [CuI(L)] with L=EtIN (1), MeIN (2) and HIN (3). Polymers 1-3 show similar structures based on a CuI double chain in which ethyl-, methyl isonicotinate or isonicotinic acid are coordinated as terminal ligands. Albeit, their supramolecular architecture differs considerably, affecting the distances and angles of the central CuI double chains and thereby their physical properties. Hence, the photoluminescence shows remarkable differences; 1 and 2 show a strong yellow emission, whereas 3 displays a…

Characterization of the interaction of the antifungal and cytotoxic cyclic glycolipopeptide hassallidin with sterol-containing lipid membranes.

2019

Hassallidins are cyclic glycolipopeptides produced by cyanobacteria and other prokaryotes. The hassallidin structure consists of a peptide ring of eight amino acids where a fatty acid chain, additional amino acids, and sugar moieties are attached. Hassallidins show antifungal activity against several opportunistic human pathogenic fungi, but does not harbor antibacterial effects. However, they have not been studied on mammalian cells, and the mechanism of action is unknown. We purified hassallidin D from cultured cyanobacterium Anabaena sp. UHCC 0258 and characterized its effect on mammalian and fungal cells. Ultrastructural analysis showed that hassallidin D disrupts cell membranes, causin…

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…

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.

Neoclerodanes from Teucrium orientale

2004

Abstract Two new neoclerodane diterpenoids, 6-deacetyl-teucrolivin A (5) and 8beta-hydroxy-teucrolivin B (6), were isolated from the aerial parts of Teucrium orientale, along with four already known neoclerodane diterpenoids, teucrolivin A (1), teucrolivin B (2), teucrolivin C (3) and teucrolivin H (4), previously isolated from Teucrium oliverianum. Their structures were elucidated on the basis of spectroscopic evidence and chemical transformations. Compounds 1-3 were assayed for antifeedant activity against Spodoptera littoralis, S. frugiperda and Heliocoverpa armigera. Teucrolivin A was the most potent of the three compounds tested.

Quantum Chemical Calculations Predict the Diphenyl Diuranium Compound [PhUUPh] To Have a Stable1Ag Ground State

2006

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.

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…

Corrosion of Heritage Objects: Collagen‐Like Triple Helix Found in the Calcium Acetate Hemihydrate Crystal Structure

2020

Abstract Helical motifs are common in nature, for example, the DNA double or the collagen triple helix. In the latter proteins, the helical motif originates from glycine, the smallest amino acid, whose molecular confirmation is closely related to acetic acid. The combination of acetic acid with calcium and water, which are also omnipresent in nature, materializing as calcium acetate hemihydrate, was now revealed to exhibit a collagen‐like triple helix structure. This calcium salt is observed as efflorescence phase on calcareous heritage objects, like historic Mollusca shells, pottery or marble reliefs. In a model experiment pure calcium acetate hemihydrate was crystallized on the surface of…

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…