Search results for " Dono"

THEORETICAL INSIGHTS ON O2 AND CO ADSORPTION ON NEUTRAL AND POSITIVELY CHARGED GOLD CLUSTERS

2006

With the aim of understanding the elementary steps governing the oxidation of CO catalyzed by dispersed or supported gold nanoclusters, the adsorption of molecular species, such as O2 and CO, on model neutral and positively charged clusters (Au(n)(m+) n = 1, 9, and 13; m = 0, 1, and 3) has been studied using an ab initio approach. The computed structural and thermodynamic data related to the binding process show that molecular oxygen interacts better with neutral clusters, acting as an electron acceptor, while CO more strongly binds to positively charged species, thus acting as an electron donor.

Designing conjugated microporous polymers for visible light-promoted photocatalytic carbon–carbon double bond cleavage in aqueous medium

2018

The production of valuable carbonyl compounds directly from alkenes via carbon–carbon double (CC) bond cleavage is a highly important reaction. As a promising alternative to traditional metal-catalyzed thermal reaction conditions, photocatalysis offers an environmentally friendly and sustainable synthetic strategy. However, most photocatalysts used so far were homogeneous, molecular and transition metal-based catalytic systems. Here, we report a structural design strategy of conjugated microporous polymers (CMPs) as a class of metal-free, heterogeneous, stable and reusable photocatalysts for visible light-promoted CC bond cleavage reaction. Via different electron donor and acceptor combinat…

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…

N-Glycosyl Amides: Removal of the Anomeric Protecting Group and Conversion into Glycosyl Donors.

2003

Synthesis and optoelectronic properties of chemically modified bi-fluorenylidenes

2016

The development of new light harvesting materials is a key issue for the progress of the research on organic & hybrid photovoltaics. Here, we report a new class of organic sensitizers based on the bi-fluorenylidene moiety as π-linker within the donor–π-linker–acceptor (D–π–A) scheme. The new dyes are endowed with electron donor and electron acceptor units at strategic positions in order to improve their electronic and light-harvesting properties. The comprehensive study of these compounds through the use of different experimental and theoretical techniques, provides an in-depth understanding of their electronic and photophysical properties, and reveal their interest as photovoltaic material…

Synthesis, modelling and characterisation of novel non-linear optical polymer containing indandionylpyridinium betaine units

1999

Abstract In the present article we report about the synthesis, quantum chemical model calculations and non-linear optical characterisation of a novel polyurethane based polymer — a bipolar organic compound N -(indan-1,3-dion-2-yl)-4- N ′, N ′-dialkyaminopyridinium betaine (IPB) containing charged electron donor and electron acceptor groups covalently bonded to polyurethane polymer backbone. This newly synthesised IPB containing polymer can be regarded as a promising thermally stable organic non-linear optical material with a long time performance for photonics applications.

Influence of the cyanine counter anions on a bi-layer solar cell performance

2013

ABSTRACTWe present normal and inverted solution processed bi-layer solar cells using cationic cyanine dyes as the electron donor and a fullerene as the electron acceptor. The cells exhibit high open circuit voltages up to 1 volt showing the optimal alignment of donor and acceptor energy levels. We demonstrate the large effect that cyanine dye counter ions can have on the energetics of the solar cells and how the S-shaped current density vs. voltage (J-V) curves can be avoided.

Dithienopyrrolobenzotriazole-based organic dyes with high molar extinction coefficient for efficient dye-sensitized solar cells

2016

Abstract Four novel organic dyes DT1-DT4 containing a dithienopyrrolobenzotriazole unit were synthesized and applied in dye sensitized solar cells, where dithienopyrrolobenzotriazole moiety was introduced as a π-spacer for the first time. The four dyes exhibited good light harvesting efficiency with high molar extinction coefficients and broad spectral response. The influence of the different electron donor on the photovoltaic performance was evaluated. The effects of the linear and branched alkyl chains in the π-bridge on the photophysical, electrochemical and photovoltaic performance were systemically investigated. The results show that branched alkyl chains are better than linear alkyl c…

The synergy between the CsPbBr3 nanoparticle surface and the organic ligand becomes manifest in a demanding carbon–carbon coupling reaction

2020

We demonstrate here the suitability of CsPbBr3nanoparticles as photosensitizers for a demanding photoredox catalytic homo- and cross-coupling of alkyl bromides at room temperature by merely using visible light and an electron donor, thanks to the cooperative action between the nanoparticle surface and organic capping. Fil: Rosa-Pardo, Ignacio. Instituto de Ciencia Molecular; España. Universidad de Valencia; España Fil: Casadevall, Carla. Barcelona Institute Of Science And Technology. Institut Català D'investigació Química.; España Fil: Schmidt, Luciana Carina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigac…