Cobalt(iii) sepulchrate complexes: application as sustainable oxidative catalysts

2014 ◽  
Vol 38 (6) ◽  
pp. 2500-2507 ◽  
Author(s):  
Susana Ribeiro ◽  
Luís Cunha-Silva ◽  
Salete S. Balula ◽  
Sandra Gago
Keyword(s):  
Crystal Structure ◽  
Homogeneous Catalysts ◽  
First Time

The application of cobalt sepulchrate (sep) complexes as active and robust homogeneous catalysts is reported here for the first time, as well as the crystal structure of the [Co(sep)]2(SO4)3·10H2O compound.

scholarly journals Investigation of Solubility Behavior of Canagliflozin Hydrate Crystals Combining Crystallographic and Hirshfeld Surface Calculations

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 298
Author(s):  
Yefen Zhu ◽  
Yanlei Kang ◽  
Ling Zhu ◽  
Kaxi Yu ◽  
Shuai Chen ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Intermolecular Forces ◽  
Hirshfeld Surface ◽  
Reversible Inhibitor ◽  
Solubility Behavior ◽  
Hydrogen Bond Networks ◽  
Solvent Molecules ◽  
First Time ◽  
Better Than

Canagliflozin (CG) was a highly effective, selective and reversible inhibitor of sodium-dependent glucose co-transporter 2 developed for the treatment of type 2 diabetes mellitus. The crystal structure of CG monohydrate (CG-H2O) was reported for the first time while CG hemihydrate (CG-Hemi) had been reported in our previous research. Solubility and dissolution rate results showed that the solubility of CG-Hemi was 1.4 times higher than that of CG-H2O in water and hydrochloric acid solution, and the dissolution rates of CG-Hemi were more than 3 folds than CG-H2O in both solutions. Hirshfeld surface analysis showed that CG-H2O had stronger intermolecular forces than CG-Hemi, and water molecules in CG-H2O participated three hydrogen bonds, forming hydrogen bond networks. These crystal structure features might make it more difficult for solvent molecules to dissolve CG-H2O than CG-Hemi. All these analyses might explain why the dissolution performance of CG-Hemi was better than CG-H2O. This work provided an approach to predict the dissolution performance of the drug based on its crystal structure.

Synthesis, crystal structure and photoluminescence properties of Eu2+-activated RbCaGd(PO4)2 phosphors

RSC Advances ◽  
2016 ◽  
Vol 6 (14) ◽  
pp. 11211-11217 ◽  
Author(s):  
Xue Chen ◽  
Qidi Wang ◽  
Fengzhu Lv ◽  
Paul K. Chu ◽  
Yihe Zhang
Keyword(s):  
Crystal Structure ◽  
Sol Gel ◽  
Dipole Interaction ◽  
Concentration Quenching ◽  
Photoluminescence Properties ◽  
Gel Method ◽  
Sol Gel Method ◽  
First Time

RbCaGd(PO4)2:Eu2+ was prepared by the Pechini-type sol–gel method. The crystal structure was determined in the first time. The dipole–dipole interaction plays a major role in the mechanism of concentration quenching of Eu2+ in this phosphor.

scholarly journals Specificity of Human Sulfiredoxin for Reductant and Peroxiredoxin Oligomeric State

Antioxidants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 946
Author(s):  
Tom E. Forshaw ◽  
Julie A. Reisz ◽  
Kimberly J. Nelson ◽  
Rajesh Gumpena ◽  
J. Reed Lawson ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Antioxidant Enzymes ◽  
Hydrogen Sulfide ◽  
Active Site ◽  
Relative Efficacy ◽  
Oligomeric Structure ◽  
Cellular Functions ◽  
Oligomeric State ◽  
Structural Requirements ◽  
First Time

Human peroxiredoxins (Prx) are a family of antioxidant enzymes involved in a myriad of cellular functions and diseases. During the reaction with peroxides (e.g., H2O2), the typical 2-Cys Prxs change oligomeric structure between higher order (do)decamers and disulfide-linked dimers, with the hyperoxidized inactive state (-SO2H) favoring the multimeric structure of the reduced enzyme. Here, we present a study on the structural requirements for the repair of hyperoxidized 2-Cys Prxs by human sulfiredoxin (Srx) and the relative efficacy of physiological reductants hydrogen sulfide (H2S) and glutathione (GSH) in this reaction. The crystal structure of the toroidal Prx1-Srx complex shows an extended active site interface. The loss of this interface within engineered Prx2 and Prx3 dimers yielded variants more resistant to hyperoxidation and repair by Srx. Finally, we reveal for the first time Prx isoform-dependent use of and potential cooperation between GSH and H2S in supporting Srx activity.

scholarly journals Unusual formation of (E)-11-(aminomethylene)-8,9,10,11-tetrahydropyrido[2′,3′:4,5]pyrimido[1,2-a]azepin-5(7H)-one and its crystal structure

2017 ◽  
Vol 73 (10) ◽  
pp. 1497-1500
Author(s):  
Khamid U. Khodjaniyazov ◽  
Utkir S. Makhmudov ◽  
Kambarali K. Turgunov ◽  
Burkhon Z. Elmuradov
Keyword(s):  
Crystal Structure ◽  
Structural Analysis ◽  
Aqueous Ammonia ◽  
Boat Conformation ◽  
X Ray ◽  
First Time ◽  
Twist Boat ◽  
Unusual Formation

Selective C-formylation of 8,9,10,11-tetrahydropyrido[2′,3′:4,5]pyrimido[1,2-a]-azepin-5(7H)-one has been studied for the first time. It was revealed that formylation proceeds by the formation of an intermediate salt, which due to the re-amination process on treatment with aqueous ammonia transformed into the corresponding (E)-11-(aminomethylene)-8,9,10,11-tetrahydropyrido[2′,3′:4,5]-pyrimido[1,2-a]azepin-5(7H)-one, C13H14N4O, as anE-isomer. Formylation was carried out by Vilsmeier–Haack reagent and the structure of the synthesized compound was confirmed by X-ray structural analysis, spectroscopic and LC–MS methods. In the molecule, the seven-membered pentamethylene ring adopts a twist-boat conformation.

scholarly journals Fedorite from Murun Alkaline Complex (Russia): Spectroscopy and Crystal Chemical Features

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 702
Author(s):  
Ekaterina V. Kaneva ◽  
Roman Yu. Shendrik ◽  
Tatiana A. Radomskaya ◽  
Ludmila F. Suvorova
Keyword(s):  
Crystal Structure ◽  
Emission Spectra ◽  
Chemical Study ◽  
Double Layers ◽  
Water Molecules ◽  
Crystal Chemical ◽  
Alkaline Complex ◽  
Deformation Parameters ◽  
First Time ◽  
Red Coloration

Fedorite is a rare phyllosilicate, having a crystal structure characterized by SiO4-tetrahedral double layers located between continuous layers formed by edge-sharing (Ca,Na)-octahedra, and containing interlayer K, Na atoms and H2O molecules. A mineralogical-petrographic and detailed crystal-chemical study of fedorite specimens from three districts of the Murun alkaline complex was performed. The sequence of the crystallization of minerals in association with fedorite was established. The studied fedorite samples differ in the content of interlayer potassium and water molecules. A comparative analysis based on polyhedral characteristics and deformation parameters was carried out. For the first time, EPR, optical absorption and emission spectra were obtained for fedorite. The raspberry-red coloration of the mineral specimens could be attributed to the presence of Mn4+ ions.

scholarly journals Structural, mechanical, spectroscopic and thermodynamic characterization of the copper-uranyl tetrahydroxide mineral vandenbrandeite

RSC Advances ◽  
2019 ◽  
Vol 9 (69) ◽  
pp. 40708-40726 ◽  
Author(s):  
Francisco Colmenero ◽  
Jakub Plášil ◽  
Joaquín Cobos ◽  
Jiří Sejkora ◽  
Vicente Timón ◽  
...  
Keyword(s):  
Crystal Structure ◽  
First Principles ◽  
Thermodynamic Characterization ◽  
First Time

The experimental full crystal structure of vandenbrandeite is stablished for the first time and verified using first-principles methods. A detailed mechanical, spectroscopic and thermodynamic characterization is obtained from the optimized structure.

O,O-diethyl O-[2-(dimethylamino)ethyl] phosphorothioate: structural evidence of the decomposition product and its oxalate salt

2019 ◽  
Vol 234 (9) ◽  
pp. 613-621
Author(s):  
Marc André Althoff ◽  
Jörn Frederik Martens ◽  
Marco Reichel ◽  
Manfred Metzulat ◽  
Thomas Matthias Klapötke ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Title Compound ◽  
Analytical Methods ◽  
Decomposition Product ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rearrangement Process ◽  
Study Support ◽  
First Time

Abstract The molecular and single crystal structure of O,O-diethyl O-[2-(dimethylamino)ethyl] phosphorothioate oxalate, as determined by single crystal X-ray diffraction studies, is described for the first time; although this compound is well-known by industry and research from the mid-20th century. The known decomposition product of pure O,O-diethyl O-[2-(dimethylamino)ethyl] phosphorothioate could also be structurally characterized. Additionally, the compounds are characterized by recent analytical methods e.g. NMR. The findings of our study support the thesis that the isolated decomposition product must be a by-product of the thiono-thiolo rearrangement process of the title compound.

scholarly journals Structural and functional studies of Arabidopsis thaliana legumain beta reveal isoform specific mechanisms of activation and substrate recognition

2020 ◽  
Vol 295 (37) ◽  
pp. 13047-13064 ◽  
Author(s):  
Elfriede Dall ◽  
Florian B. Zauner ◽  
Wai Tuck Soh ◽  
Fatih Demir ◽  
Sven O. Dahms ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Arabidopsis Thaliana ◽  
Cyclic Peptides ◽  
Molecular Mechanisms ◽  
Functional Studies ◽  
Plant Characteristic ◽  
Activation Mechanisms ◽  
Binding Pockets ◽  
First Time ◽  
Autocatalytic Activation

The vacuolar cysteine protease legumain plays important functions in seed maturation and plant programmed cell death. Because of their dual protease and ligase activity, plant legumains have become of particular biotechnological interest, e.g. for the synthesis of cyclic peptides for drug design or for protein engineering. However, the molecular mechanisms behind their dual protease and ligase activities are still poorly understood, limiting their applications. Here, we present the crystal structure of Arabidopsis thaliana legumain isoform β (AtLEGβ) in its zymogen state. Combining structural and biochemical experiments, we show for the first time that plant legumains encode distinct, isoform-specific activation mechanisms. Whereas the autocatalytic activation of isoform γ (AtLEGγ) is controlled by the latency-conferring dimer state, the activation of the monomeric AtLEGβ is concentration independent. Additionally, in AtLEGβ the plant-characteristic two-chain intermediate state is stabilized by hydrophobic rather than ionic interactions, as in AtLEGγ, resulting in significantly different pH stability profiles. The crystal structure of AtLEGβ revealed unrestricted nonprime substrate binding pockets, consistent with the broad substrate specificity, as determined by degradomic assays. Further to its protease activity, we show that AtLEGβ exhibits a true peptide ligase activity. Whereas cleavage-dependent transpeptidase activity has been reported for other plant legumains, AtLEGβ is the first example of a plant legumain capable of linking free termini. The discovery of these isoform-specific differences will allow us to identify and rationally design efficient ligases with application in biotechnology and drug development.

Human 3α-hydroxysteroid dehydrogenase type 3: structural clues of 5α-DHT reverse binding and enzyme down-regulation decreasing MCF7 cell growth

2016 ◽  
Vol 473 (8) ◽  
pp. 1037-1046 ◽  
Author(s):  
Bo Zhang ◽  
Xiao-Jian Hu ◽  
Xiao-Qiang Wang ◽  
Jean-François Thériault ◽  
Dao-Wei Zhu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Crystal Structure ◽  
Cell Growth ◽  
Mcf7 Cell ◽  
Hydroxysteroid Dehydrogenase ◽  
Cancer Cell Growth ◽  
Down Regulation ◽  
Breast Cancer Cell Growth ◽  
Type 3 ◽  
First Time

Human 3α-HSD3 (3α-hydroxysteroid dehydrogenase type 3) plays an essential role in the inactivation of the most potent androgen 5α-DHT (5α-dihydrotestosterone). The present study attempts to obtain the important structure of 3α-HSD3 in complex with 5α-DHT and to investigate the role of 3α-HSD3 in breast cancer cells. We report the crystal structure of human 3α-HSD3·NADP+·A-dione (5α-androstane-3,17-dione)/epi-ADT (epiandrosterone) complex, which was obtained by co-crystallization with 5α-DHT in the presence of NADP+. Although 5α-DHT was introduced during the crystallization, oxidoreduction of 5α-DHT occurred. The locations of A-dione and epi-ADT were identified in the steroid-binding sites of two 3α-HSD3 molecules per crystal asymmetric unit. An overlay showed that A-dione and epi-ADT were oriented upside-down and flipped relative to each other, providing structural clues for 5α-DHT reverse binding in the enzyme with the generation of different products. Moreover, we report the crystal structure of the 3α-HSD3·NADP+·4-dione (4-androstene-3,17-dione) complex. When a specific siRNA (100 nM) was used to suppress 3α-HSD3 expression without interfering with 3α-HSD4, which shares a highly homologous active site, the 5α-DHT concentration increased, whereas MCF7 cell growth was suppressed. The present study provides structural clues for 5α-DHT reverse binding within 3α-HSD3, and demonstrates for the first time that down-regulation of 3α-HSD3 decreases MCF7 breast cancer cell growth.

Crystal Structure of a Novel Furo-Furan Lactone from Heliotropium eichwaldi

2012 ◽  
Vol 67 (3) ◽  
pp. 269-271
Author(s):  
Sadiqa Firdous ◽  
Nida Hassan Ansari ◽  
Seik Weng Ngb ◽  
Sammer Yousuf ◽  
Abdul Malik
Keyword(s):  
Crystal Structure ◽  
Ethyl Acetate ◽  
Soluble Fraction ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Report ◽  
First Time

A novel furo-furan lactone 1 has been isolated as fine needles from the ethyl acetate-soluble fraction of Heliotropium eichwaldi. This is the first report of any furo-furan from the genus Heliotropium. β -Sitosterol 3-O-β -D-glucoside 2 has also been obtained for the first time from this source. The structure of 1 was elucidated by X-ray diffraction studies.

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