Search results for "ELECTRON TRANSFER"
showing 10 items of 282 documents
Mimicking photosynthesis: covalent [60]fullerene-based donor–acceptor ensembles
2004
Abstract Within the context of exploring photophysical properties of [60]fullerene-based donor–acceptor ensembles, we highlight in this contribution an approach towards the synthesis of a novel series of donor-bridge-acceptor, C 60 –wire– ex TTF , ensembles that incorporate p -phenylenevinylene oligomers, in which the conjugation length has been systematically increased, as bridges that connect π-extended tetrathiafulvalenes (exTTF) (electron donor) with [60]fullerene (electron acceptor). This molecular design allows probing the effects of distance and rate, at which electron transfer processes occur, as well as the molecular-wire behavior of the oligo-PPV fragments.
Electronic communication through pi-conjugated wires in covalently linked porphyrin/C60 ensembles
2005
Novel photo- and electroactive triads, in which pi-conjugated p-phenylenevinylene oligomers (oPPVs) of different length are connected to a photoexcited-state electron donor (i.e., zinc tetraphenylporphyrin) and an electron acceptor (i.e., C(60)), were designed, synthesized, and tested as electron-transfer model systems. A detailed physicochemical investigation, concentrating mainly on long-range charge separation and charge recombination and kinetics, revealed small attenuation factors beta of 0.03+/-0.005 A(-1). Energy matching between the HOMO levels of C(60) and oPPVs emerged as a key parameter for supporting molecular-wire-like behavior: It favors rapid and efficient electron or hole in…
Diferrocenyl tosyl hydrazone with an ultrastrong NHFe hydrogen bond as double click switch.
2014
The intramolecular NH⋯Fe hydrogen bond in diferrocenyl hydrazone 2 raises the barrier for intramolecular electron transfer in its mixed-valent cation 2+ and is only disrupted by double oxidation to 22+.
Electrochemical study on a tricyclic 1,1,1-tricar-bonyl-2,3-1 diazaferrole derivative. II. Activation of carbon monoxide replacement by electron tran…
1986
Etudes, par voltammetrie cyclique, de la reduction electrochimique du complexe de diazaferratricyclodecene, en presence de P(OMe) 3
Chemical and spectroscopical evidence for an electron‐transfer mechanism in the reaction of arenesulfonyl chlorides with anions
1989
The reaction of amide and amidate anions 2 with p-toluenesulfonyl chloride (1) under different reaction conditions gives rise to the total or partial reduction of the acyl halide to p-toluenesulfinic acid (5) and acylation compounds in variable amounts depending on the crowding at the anionic center. This indicates that a Single-Electron Transfer (SET) mechanism is involved in the reactions of 1 with anions. Unpaired electron species are detected by ESR in the course of the reactions.
Homocoupling of terminal alkynes on calcite (10.4)
2018
Abstract On-surface synthesis has been identified as highly versatile strategy to prepare molecular structures on surfaces with single-atom precision. Inspired by the classical Glaser coupling, homocoupling of terminal alkynes has attracted great attention for on-surface synthesis. This coupling is known for providing a rigid and linear linkage, which is highly interesting for the synthesis of molecular wires. For molecular wire formation, non-conductive substrates are needed for electronic decoupling. So far, however, coupling of terminal alkynes has not been performed on a bulk insulator surface. Here, we present an atomic force microscopy study, indicating that 4,4″-diethynyl-[1,1′:4′,1″…
Enzyme-modified electrodes for biosensors and biofuel cells
2019
In biosensors and biofuel cells, it is often desirable to accelerate the electron transfer rate between the enzyme and electrode surface to improve the performance of the devices (sensitivity or power output). To this end, in this review, we focus on three important strategies available to improve the performance of enzyme-modified electrodes: the use of protein engineering, designer polymers, and the introduction of nanomaterials. Engineering the protein or proteins that constitute the biocatalytic elements allow tuning their stability, activity, and specificity. It can also allow changing the enzyme immobilization efficiency (adsorption vs. covalent immobilization, for example). If direct…
The role of intermolecular forces in contact electrification on polymer surfaces and triboelectric nanogenerators
2019
This research was supported by the European Regional Development Fund within the project ‘‘Hybrid energy harvesting systems’’ 1.1.1.1./16/A/013.
MODIFICATION OF HUMIC SUBSTANCES FOR DEVELOPMENT OF MATERIALS FOR ENVIRONMENTAL TECHNOLOGIES
2019
Humic substances are high molecular weight refractory polycationites formed during decay of living organic matter and through biosynthesis of low molecular weight organic substances (metabolites or decay products of living organisms). Presence of many functional groups in the structure of humic substances determines their ability to interact with metal ions forming stable complexes and influencing metal ion speciation in the environment and mobility, behaviour and speciation forms in the environment. Presently humic substances are a product of industrial scale and quantities in amounts of hundreds of tons are produced. The aim of this study is to analyse derivatization possibilities of humi…
The Quest for Mononuclear Gold(II) and Its Potential Role in Photocatalysis and Drug Action.
2017
The chemistry of gold strongly focuses on the ubiquitous oxidation states +I and +III. The intermediate oxidation state +II is generally avoided in mononuclear gold species. In recent years, gold(II) has been increasingly suggested as a key intermediate in artificial photosynthesis systems, with gold(III) moieties acting as electron acceptors, as well as in gold-catalyzed photoredox catalysis and radical chemistry. This Minireview provides a concise summary of confirmed and characterized mononuclear open-shell gold(II) complexes. Recent findings on structural motifs and reactivity patterns will be discussed. Exciting developments in the fields of photosynthesis, photocatalysis, and potentia…