Search results for "synthesi"

Three-dimensional crystallization of the light-harvesting complex from Mantoniella squamata (Prasinophyceae) requires an adequate purification proced…

1995

Abstract We present a new purification procedure for the light-harvesting complex of Mantoniella squamata whereupon three-dimensional crystallization succeeded. Previous purification methods were based on density centrifugations as the only separating principle. We have extended this preparation procedure by applying anion-exchange and molecular-sieve chromatography techniques. Purity and stability of the complex were proved by denaturing and non-denaturing polyacrylamide-gel electrophoresis, and spectroscopic measurements. With respect to contaminating lipids the purified pigment-protein complex was examined by thin-layer chromatography and the aggregation and/or oligomeric states were inv…

Savaime sklindančios aukštatemperatūrinės sintezės būdu gautų aliuminio oksinitrido miltelių ir jų keramikų optinės savybės

2021

The reported study was funded by RFBR according to the Research Project No. 19-08-00655. V.P. acknowledges the State Research Program ‘Aug-stas enerģijas fizika un paātrinātāju tehnoloģijas’ (Projekta Nr. VPP-IZM-CERN-2020/1-0002). The Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the H2020-WIDESPREAD-01-2016-2017-Teaming Phase2 under Grant Agreement No. 739508, Project CAMART2.

A multilayer model for self-propagating high-temperature synthesis of inter-metallic compounds

2007

International audience; Self-propagating high-temperature synthesis of intermetallic compounds is of wide interest. We consider reactions in a binary system in which the rise and fall of the temperature during the reaction is such that one of the reacting metals melts but not the other. For such a system, using the phase diagram of the binary system, we present a general theory that describes the reaction taking place in a single solid particle of one component surrounded by the melt of the second component. The theory gives us a set of kinetic equations that describe the propagation of the phase interfaces in the solid particle and the change in composition of the melt that surrounds it. I…

Continuous hydrothermal synthesis in supercritical conditions as a novel process for the elaboration of Y-doped BaZrO3

2021

Abstract The present work describes a novel process for the elaboration of a ceramic material. Y-doped barium zirconate, an electrolyte material for Protonic Ceramic Fuel cell, was synthesized by a continuous hydrothermal process in supercritical conditions (410 °C/30.0 MPa) using nitrate precursors and NaOH reactants. The use of supercritical water allowed the formation of particles of about 50 nm in diameter with a narrow size distribution. X-Ray Diffraction examination revealed that a major perovskite phase with few BaCO3 and YO(OH) impurities was obtained. BaCO3 is assumed to form due to faster kinetics than Y-doped BaZrO3 resulting in a Ba-deficient perovskite phase. The Ba-deficiency …

Enantioselective synthesis of 4H-pyranonaphthoquinones via sequential squaramide and silver catalysis

2015

Chemical communications 52(8), 1669-1672(2016). doi:10.1039/C5CC09592A

Phosphasalen group IV metal complexes: synthesis, characterization and ring opening polymerization of lactide.

2020

International audience; We report the synthesis of a series of Zr and Ti complexes bearing phosphasalen which differs from salen by the incorporation of two P atoms in the ligand backbone. The reaction of phosphasalen proligands (1a-1c)H2 with Zr(CH2Ph)4 led to different products depending on the nature of the N,N-linker in the ligand. In case of ethylene-linked phosphasalen, octahedral Zr complex 2a formed as a single stereoisomer in trans geometry. With the phenylene linker, it was shown by dynamic NMR spectroscopy that complex 2b exists as a mixture of trans and cis-β isomers in solution, both enantiomers (Δ and Λ) of the cis-β isomer being in fast equilibrium with respect to the NMR tim…

A green and efficient method for the synthesis of homodimeric (β-dicarbonyl) arylmethanes and dihydropyridine from dimedone in water

2018

A direct method has been developed for the synthesis of the dihydropyridine ring system by means of Michael reaction. The reaction of dimedone with 1 .0 equiv. of amines in water provides intermediate product, which allowed dihydropyridine derivatives by intramolecular cyclization in various yields. Of particular interest is the use of the water as solvent of reaction and in absence of catalyst. Also these operating conditions protect the environment and economic points of view.Keywords: aqueous synthesis; bioactivity; dihydropyridine; dimedone; green method; selective conditions

Synthesis of P-Chirogenic Diphosphinotriazoles and Their Use in Asymmetric Catalysis

2021

International audience; The stereoselective synthesis of P-chirogenic diphosphinotriazoles using ephedrine methodology was described. The coordination behavior of these compounds as P,P-ligands has been demonstrated by the preparation as well as the spectroscopic and X-ray crystallographic analyses of a palladium complex. The efficiency of these new P-chirogenic diphosphines in the palladiumcatalyzed asymmetric allylic substitution reaction was also evaluated.

Synthesis of Lamellarin G Trimethyl Ether by von Miller-Plöchl-Type Cyclocondensation

2018

Chiral footprint of the ligand layer in the all-alkynyl-protected gold nanocluster Au144(CCPhF)60

2019

The electronic structure and chiroptical properties of the recently isolated and structurally characterized all-alkynyl-protected gold nanocluster Au144(CCPhF)60 were analyzed via density functional theory (DFT) computations and compared to those of the structurally similar all-thiolate-protected Au144(SCH2Ph)60. While DFT predicts very strong CD signals of similar strength for both clusters, the origins of chiroptical activity are markedly different. The chiral response of Au144(CCPhF)60 originates only from the footprint of the outermost gold-ligand layer of 30 FPhCC-Au-CCPhF units covering an achiral Ih-symmetric Au114 core whereas the Au114 core of the Au144(SCH2Ph)60 cluster has a chir…