Search results for "Conjugate"
showing 10 items of 644 documents
Redox properties of nitrophenylporphyrins and electrosynthesis of nitrophenyl-linked Zn porphyrin dimers or arrays
2014
Five nitrophenylporphyrins were investigated as to their electrochemical properties in CH 2 Cl 2 containing 0.1 M TBAP. The investigated compounds are represented as ( NO 2 Ph )x Ph 4-x PorM , where Por represents the dianion of the porphyrin macrocycle, Ph is a phenyl group on meso-position of the macrocycle, NO 2 Ph is a meso-substituted nitrophenyl group, M = 2 H , Pd II or Zn II and x = 1 or 2. Each porphyrin undergoes an initial one electron reduction at E1/2 = -1.07 to -1.12 V where the added negative charge is almost totally localized on the meso-nitrophenyl group of the compound. This reversible reduction is then followed by one or more irreversible reductions of the nitrophenyl an…
Photochemical generation of benzene–naphthalene biplanemers
2005
Abstract A direct biplanemer synthesis could be achieved by a quantitative [4π+4π]photocycloaddition of benzyloxy substituted benzene and naphthalene rings ( 3d , e ⇄ 4d , e ). Since the products do not show a thermal Cope rearrangement—in contrast to the related longicyclic conjugated 9,10-benzotricyclo[4.2.2.2 2,5 ]dodeca-3,7,9-trienes—but a quantitative reverse reaction, they are interesting systems for an optical switching.
Palladium-based catalytic systems for the synthesis of conjugated enynes by Sonogashira reactions and related alkynylations
2007
Conjugated alkynes are recurring building blocks in natural products, a wide range of industrial intermediates, pharmaceuticals and agrochemicals, and molecular materials for optics and electronics. The palladium-catalyzed cross-coupling between sp(2)-hybridized carbon atoms of aryl, heteroaryl, and vinyl halides with sp-hybridized carbon atoms of terminal acetylenes is one of the most important developments in the field of alkyne chemistry over the past 50 years. The seminal work of the 1970s has initiated an intense search for more general and reliable reaction conditions. The interest in the catalytic activation of demanding substrates, the need to minimize the consumption of depletive r…
First Chemosensor for Selective Detection and Quantification of L-4-Hydroxyproline in Collagen and Other Bio Samples.
2017
Amino pyridine-based rhodamine conjugate (APR) has been developed as a first chemosensor for selective detection and quantification of L-4-Hydroxyproline (Hyp). The “turn-on” fluorescence property of the chemosensor makes it unique for easy estimation of Hyp in collagen and biological samples. peerReviewed
Second order optimality conditions with applications
2007
International audience; The aim of this article is to present the algorithm to compute the first conjugate point along a smooth extremal curve. Under generic assump- tions, the tra jectory ceases to be optimal at such a point. An implementation of this algorithm, called cotcot, is available online and based on recent devel- opments in geometric optimal control. It is applied to analyze the averaged optimal transfer of a satellite between elliptic orbits.
Second order optimality conditions in optimal control with applications
2006
The aim of this article is to present the algorithm to compute the first conjugate point along a smooth extremal curve. Under generic assumptions, the trajectory ceases to be optimal at such a point. An implementation of this algorithm, called \texttt{cotcot}, is available online and based on recent developments in geometric optimal control. It is applied to analyze the averaged optimal transfer of a satellite between elliptic orbits.
Electrocatalytic properties of manganese and cobalt polyporphine films toward oxygen reduction reaction
2018
International audience; Novel member of polymetalloporphines, namely manganese polymetalloporphine of type I (pMnP-I) obtained by ion exchange from magnesium polyporphine of type I (pMgP-I) is reported for the first time and compared to its cobalt analogue (pCoP-I). Both polymer films have been obtained via two-step procedure: demetaladon of the pMgP-I electrode film via its exposure to trifluoroacetic acid solution, resulting in formation of the metal-free polyporphine of type I (pH(2)P-I) followed by electrochemically induced incorporation of Co or Mn ions from the acetonitrile solution of cobalt and manganese perchlorates. A further oxidative transformation of pCoP-I, polymer films has l…
PHEA-Dox nanoparticles as pH-sensitive model for drug delivery in tumour treatment.
2015
PHEA-Dox nanoparticles as pH-sensitive model for drug delivery in tumour treatment. S. Camporaa, G. Adamoa, N. Maurob, C. Scialabbab, M. Licciardib, G. Giammonab and G. Ghersia. aDipartmento di “Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche” (STEBICEF), Università di Palermo, Viale delle Scienze Ed. 16, 90128 Palermo, Italy. bLaboratory of Biocompatible Polymers, Dipartmento di “Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche” (STEBICEF), Università di Palermo, Via Archirafi, 32 90123 Palermo, Italy. Classical chemotherapeutic applications, using molecules such as doxorubicin (Dox), have side effects due to an unspecific action. In order to obtain a specific release of…
On the synthesis of functionalized porphyrins and porphyrin conjugates via β-aminoporphyrins
2016
International audience; The synthesis of functionalized porphyrins and their conjugates from meso-tetraarylporphyrins through the acylation and the oxidation of beta-aminoporphyrins was investigated. 2,3-Dioxochlorins were prepared by the oxidation of a variety of beta-aminoporphyrins and subsequently used in a condensation reaction with functionalized aromatic aldehydes and ammonium acetate to form beta-functionalized porphyrins bearing a fused imidazole ring. Under optimized experimental conditions both reactions tolerate various functional groups and afford the products in an appropriate overall yield. The mildness and usefulness of this methodology are illustrated by several examples in…
Effect of conjugated system extension on structural features and electron-density distribution in charge–transfer difluoroborates
2021
A comparative structural study of two related donor–acceptor pyridine-based BF2 complexes, namely, 3-(dimethylamino)-1,1-difluoro-1H-pyrido[1,2-c][1,3,5,2]oxadiazaborinin-9-ium-1-uide, C8H10BF2N3O (1), and 3-{(1E,3E)-4-[4-(dimethylamino)phenyl]buta-1,3-dien-1-yl}-1,1-difluoro-1H-pyrido[1,2-c][1,3,5,2]oxadiazaborinin-9-ium-1-uide, C18H18BF2N3O (2), containing a dimethylamino group and either the shortest (in 1) or the longest (in 2) charge-transfer path known until now in this family of compounds, is presented. Single-crystal X-ray diffraction analysis supported by computational investigations shed more light on these systems, indicating, among other aspects, the predominance of C—H...F cont…