نتایج جستجو برای: molecular catalyst

تعداد نتایج: 676548  

Journal: :Biomacromolecules 2013
Assunta Nuzzo Alessandro Piccolo

The meso-tetra(2,6-dichloro-3-sulfonatophenyl)porphyrinate of manganese(III) chloride [Mn-(TDCPPS)Cl] biomimetic catalyst immobilized on spacer-functionalized kaolinite clay mineral was employed in the oxidative coupling reaction of a dissolved humic acid (HA) suprastructure with either chemical (H2O2) or UV-light oxidation. The changes in molecular size of humic matter subjected to catalyzed o...

Journal: :Molecules 2016
Yanning Zeng Qaiser Mahmood Tongling Liang Wen-Hua Sun

A new pair of plladium complexes (Pd4 and Pd5) ligated with constrained N-(5,6,7-trihydroquinolin-8-ylidene)arylamine ligands have been prepared and well characterized by ¹H-, 13C-NMR and FTIR spectroscopies as well as elemental analysis. The molecular structure of Pd4 and Pd5 in solid state have also been determined by X-ray diffraction, showing slightly distorted square planar geometry around...

Journal: :Science 1985
G A Somorjai

During the last 20 years, surface scientists have developed a variety of techniques that make it possible to study, on the molecular level, the structure, composition, and chemical bonding in the surface monolayer. Both single-crystal model catalysts and real catalyst systems that are active in important chemical processes have been investigated by a combination of ultrahigh-vacuum surface scie...

2008
Patrick Maier Gudrun Klinker

Modeling of molecular catalysts in chemistry is still a time consuming process. Where chemists design new catalysts in 2D on a screen or a paper, for making special molecules with a defined chirality, Augmented Chemistry provides an efficient way for designing and interacting with the molecules. This helps to understand the spatial relations between catalyst and reacting molecules and accelerat...

Journal: :Nanoscale 2014
Ying Wang Alister J Page Hai-Bei Li Hu-Jun Qian Meng-Gai Jiao Zhi-Jian Wu Keiji Morokuma Stephan Irle

Quantum chemical molecular dynamics simulations of graphene nucleation on the Ni(111) surface show that graphene creates its own step-edge as it forms. This "step-edge self-assembly" is driven by the formation of thermodynamically favorable Ni-C σ-bonds at the graphene edge. This dynamic aspect of the Ni(111) catalyst is in contrast to the commonly accepted view that graphene nucleates on a pre...

2006
Michelle Gilhespy Martin Lok Xavier Baucherel

PS-TEMPO, a polymer-supported 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) was successfully applied as a recyclable, active and selective catalyst for the oxidation of alcohols. Bleach, molecular oxygen and air were successfully used as terminal oxidant under conditions suitable for industrial applications. The intrinsic activity and selectivity of TEMPO for primary alcohols to aldehydes were r...

Journal: :ACS nano 2010
Yoshifumi Izu Junichiro Shiomi Yoshiteru Takagi Susumu Okada Shigeo Maruyama

We report a numerical investigation on the catalytic growth mechanism of a single-walled carbon nanotube (SWNT) inside a template SWNT, that is, formation of a double-walled carbon nanotube (DWNT). The molecular dynamics simulations together with complementary ab inito calculations suggest that the DWNT formation from thermally annealed metallocene-encapsulating SWNT goes through formation of m...

2017
Jolene P Reid Jonathan M Goodman

Choosing the optimal catalyst for a new transformation is challenging because the ideal molecular requirements of the catalyst for one reaction do not always simply translate to another. Large groups at the 3,3' positions of the binaphthol rings are important for efficient stereoinduction but if they are too large this can lead to unusual or poor results. By applying a quantitative steric asses...

Journal: :The journal of physical chemistry. B 2006
Feng Ding Arne Rosén Eleanor E B Campbell Lena K L Falk Kim Bolton

A new model is proposed for the encapsulation of catalyst metal particles by graphite layers that are obtained, for example, in low-temperature chemical vapor deposition production of carbon nanotubes (CNTs). In this model graphite layers are primarily formed from the dissolved carbon atoms in the metal-carbide particle when the particle cools. This mechanism is in good agreement with molecular...

Journal: :Dalton transactions 2015
Nilusha Priyadarshani Bojana Ginovska J Timothy Bays John C Linehan Wendy J Shaw

Inspired by nature's ability to regulate catalysis using physiological stimuli, azobenzene was incorporated into Rh(bis)diphosphine CO2 hydrogenation catalysts to photoinitiate structural changes to modulate the resulting catalytic activity. The rhodium bound diphosphine ligands (P(Ph2)-CH2-N(R)-CH2-P(Ph2)) contain the terminal amine of a non-natural amino acid, with the R-group being either β-...

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