Search results for "Catalysis"

Exploiting Palladium-Catalyzed Cross-Coupling for the Synthesis of 2-Aryl-Substituted 1-Aminocyclopropylphosphonates

2015

A series of 2-aryl-substituted 1-aminocyclopropylphosphonates containing an additional remote phosphonate group have been synthesized starting from readily accessible dimethyl (1 R *,2 R *)-2-(4-bromophenyl)-1-formamidocyclopropylphosphonate using cross-coupling methodology. Different types of palladium-catalyzed reactions for carbon–carbon and carbon–phosphorus bond formation were realized. In each case the optimum conditions were found to obtain the desired products in high yield in both small- and large-scale experiments.

A Tetrameric Nickel(II) “Chair” with both Antiferromagnetic Internal Coupling and Ferromagnetic Spin Alignment

2001

WS 2 /MoS 2 Heterostructures through Thermal Treatment of MoS 2 Layers Electrostatically Functionalized with W 3 S 4 Molecular Clusters

2020

The preparation of 2D stacked layers combining flakes of different nature gives rise to countless numbers of heterostructures where new band alignments, defined at the interfaces, control the electronic properties of the system. Among the large family of 2D/2D heterostructures, the one formed by the combination of the most common semiconducting transition metal dichalcogenides, WS2 /MoS2 , has awakened great interest owing to its photovoltaic and photoelectrochemical properties. Solution as well as dry physical methods have been developed to optimize the synthesis of these heterostructures. Here, a suspension of negatively charged MoS2 flakes is mixed with a methanolic solution of a cationi…

Ferromagnetic Coupling through Spin Polarization in a Dinuclear Copper(II) Metallacyclophane.

2001

[DT] Von organischen Radikalen zu Metallkomplexen konnte das bekannte Konzept für Ferroelektrika erfolgreich ausgedehnt werden: Die Abbildung zeigt ein Cyclophan-artiges Molekül mit einem Triplett-Grundzustand, in dem zwei CuII-Zentren von einem doppelten m-Phenylendiamid-Gerüst zusammengehalten werden.

Modular synthesis of tetrasubstituted imidazoles and trisubstituted oxazoles by aldimine cross-coupling.

2008

Functionalization of Graphene with Molecules and/or Nanoparticles for Advanced Applications

2019

Graphene is considered the material of the third millennium, due to its extraordinary electronic and mechanical properties, and due to the possibility to modulate its conductivity, flexibility, elasticity, transparency, and biocompatibility by bottom-up approach. The possibility to gather the proper- ties of graphene and graphene oxide with those of functional moieties or nanoparticles is herein reviewed. The synthetic approaches proposed, either covalent or noncovalent, are aimed to tune appropriately graphene’s properties for the realization of materials for advanced uses, such as bio- medical applications, sensors, catalysis, and energy devices. In particular, methods based on covalent l…

Kinetic control in the chiral recognition of three-bladed propellers

2010

The ion pair of the stereolabile C(3)-symmetric, i(+)o proton complex [1H](+) of diaza-macropentacycle 1 and the configurationally stable Delta-TRISPHAT ([Delta-3](-)) anion exists in the form of two diastereomers, namely, [Delta-(1.H)][Delta-3] and [Lambda-(1.H)][Delta-3], the ratio of which, in terms of diastereomeric excess (de) decreases in the order [D(8)]THF (28%)CD(2)Cl(2) (22%)CDCl(3) (20%)[D(8)]toluene (16%)C(6)D(6) (7%)[D(6)]acetone (0%) at thermodynamic equilibrium. Except in the case of [D(6)]acetone, the latter is reached after a period of time that increases from 1 h ([D(8)]THF) to 24 h (CDCl(3)). Moreover, the initial value of the de of [1.H][Delta-3] in CDCl(3), before the t…

Synthesis of (-)-Cryptopleurine by Combining Gold(I) Catalysis with a Free Radical Cyclization

2015

(R)-(–)-Cryptopleurine, a highly cytotoxic alkaloid found in Cryptocarya and Boehmeria species, was synthesized in high optical purity using a gold(I)-NHC catalyzed cyclization of an unsymmetrical phenanthrene precursor combined with a free radical cyclization to achieve closure of the C-ring.

Synthesis of (-)-Cryptopleurine by Combining Gold(I) Catalysis with a Free Radical Cyclization (Eur. J. Org. Chem. 10/2015)

2015

Design of stable mixed-metal MIL-101(Cr/Fe) materials with enhanced catalytic activity for the Prins reaction

2020

[EN] This work highlights the benefit of designing mixed-metal (Cr/Fe) MOFs for enhanced chemical stability and catalytic activity. A robust and stable mixed-metal MIL-101(Cr/Fe) was prepared through a HF-free direct hydrothermal route with Fe(3+)content up to 21 wt%. The incorporation of Fe(3+)cations in the crystal structure was confirmed by(57)Fe Mossbauer spectrometry. The catalytic performance of the mixed metal MIL-101(Cr/Fe) was evaluated in the Prins reaction. MIL-101(Cr/Fe) exhibited a higher catalytic activity compared to MIL-101(Cr), improved chemical stability compared to MIL-101(Fe) and a higher catalytic activity for bulky substrates compared to MIL-100(Fe).In situinfra-red sp…