Search results for " electrochemistry"
showing 7 items of 67 documents
CO2 as a C1-organic building block: Electrocarboxylation of aromatic ketones. A quantitative study of the effect of the concentration of substrate an…
2006
The purpose of this work is to establish and discuss quantitative relationships between the selectivity in preparative scale electrolysis and intrinsic and operational parameters for the electrocarboxylation of aromatic ketones. For the investigated ketones, under appopriate experimental conditions the selectivity of the process is mainly determined by the competition between carboxylation and protonation, de-halogenation reactions (when an halogenated ketone is involved), and possibly dimerizations involving the electrogenerated radical anion. A simple model was proposed to account for these unwanted side paths which allows to predict the dependence of the selectivity as a function of the …
Cathodic behaviour of dicationic imidazolium bromides: the role of the spacer
2019
The cathodic reduction of dicationic imidazolium bromides, whose spacer is either an aliphatic chain or a xylyl group, leads to the formation of the corresponding N-heterocyclic carbenes (NHCs), which were isolated as the corresponding thiones, after reaction with elemental sulfur. The behaviour of the dications was compared with the corresponding monocations. The behaviour of dicarbenes depends on the nature of the spacer. This study evidenced that dicarbenes deriving from xylyl dications are less stable than the corresponding aliphatic ones (giving lower yields in thiones), due to a debenzylation reaction. On the other hand, the yields in thiones starting from aliphatic dications are high…
Electrochemical monitoring of the oxidative coupling of alkynes catalyzed by triphenylphosphine gold complexes
2012
Electrochemical monitoring of the oxidative coupling of alkynes in the homogeneous phase through catalytic cycles involving triphenylphosphine gold complexes and selectfluor as oxidant reveals that at least two gold species in +3 and +1 oxidation states are implicated. Electrochemically driven homocoupling of terminal alkynes using molecular oxygen as the oxidant can be performed using such catalysts. Keywords: Gold catalysis, Oxidative coupling of alkynes, Oxygen, Voltammetry
Chiral Magneto-Electrochemistry
2018
Magneto-electrochemistry (MEC) is a unique paradigm in science, where electrochemical experiments are carried out as a function of an applied magnetic field, creating a new horizon of potential scientific interest and technological applications. Over time, detailed understanding of this research domain was developed to identify and rationalize the possible effects exerted by a magnetic field on the various microscopic processes occurring in an electrochemical system. Notably, until a few years ago, the role of spin was not taken into account in the field of magneto-electrochemistry. Remarkably, recent experimental studies reveal that electron transmission through chiral molecules is spin se…
Crosslinking of polymers activated by electrogenerated hydroxyl radicals.
2015
Nanogels (NGs) are systems created by crosslinking of polymers taking nanosized dimensions and they have been proposed for biomedical and pharmaceutical applications due to their soft consistency, biocompatibility and good chemical properties that make them excellent drug delivery agents (1). Differently from typical hydrogels, nanogels are able to dissolve in solvents and to swell releasing the drug molecules loaded in the nano-vector. Furthermore, if properly functionalized with reactive groups, these materials can represent a very interestingly vector for different pharmacological treatments (2). Several methods have been investigated to prepare polymeric nanogels starting from preformed…
Net currents obtained from zero-average potentials in single amphoteric nanopores
2013
We have studied experimentally and theoretically the rectifying properties of a single asymmetric nanopore functionalized with amphoteric lysine groups and characterized the net current obtained with zero-average time dependent potentials. The pH-controlled rectification phenomena may be relevant to bio-electrochemistry, pH sensing and regulation, and energy conversion. (C) 2013 Elsevier B.V. All rights reserved.
Contribution to the modeling of microstructural corrosion on aluminium alloys : definition of a methodology to study the bimetallic corrosion phenome…
2008
The initiation and the propagation of aluminum alloys microstructural corrosion is mainly based on the bimetallic corrosion phenomenon. This type of corrosion is caused by galvanic coupling at a local scale between the different phases contained in the alloy. The description of the localized corrosion phenomenon has been largely studied. Their complexity can explain why they are so difficult to predict by the way of numerical tools and why the works that have been done on this subject are so scarce. The present thesis brings a new contribution to this field by suggesting a methodology based on the complementary use of local electrochemical techniques and the finite element simulation of bim…