Search results for "Cyclam"
showing 10 items of 72 documents
ChemInform Abstract: A New Synthesis of Macrotricyclic Ligand Based on 1,4,8,11- Tetraazacyclotetradecane.
2010
Abstract A convenient five-step synthesis of a cylindrical macrotricyclic ligand containing two cyclam units linked together by two m-xylyl bridges is reported starting from “trans” dioxocyclam as diprotected macrocycle.
Arylation of polyamines by perfluoroarenes
2000
Abstract The conditions of selective mono- and diarylation of diamines, and di- and triarylation of triamines by perfluoroarenes are described. The introduction of four perfluoroaryl groups in cyclam and two groups in dioxocyclam has been carried out.
First unequivocal synthesis of dissymmetrical trans N,N′-difunctionalized 1,4,8,11-tetraazacyclotetradecane
1999
Abstract The first unequivocal synthesis of disymmetrical trans N,N′-difunctionalized tetraazamacrocycles in cyclam series is reported. This convenient four-step method can be used for the synthesis of various trans N,N′-difunctionalized tetraazamacrocycles bearing two different pendant donor arms.
Cyclam-strapped porphyrins and their iron(III)-copper(II) complexes as models for the resting state of cytochrome c oxidase
1999
International audience; The ESR study of two cyclam-strapped porphyrins in which, on one side, the cyclam is attached with a variable length linker to the porphyrin and, on the other side, a non-coordinating strap protects the iron from any intermolecular interaction, is reported. Variation of the linker length is made possible by the use of either a Michael reaction or a nucleophilic substitution, leading respectively to three or two carbon atom links. It is shown that in the case of the shortest link, the oxidized ironÈcopper complex exhibits a spin interaction. The distance between thetwo metal centers is evaluated to be around 4.5 Å, a value consistent with the one found in the natural …
Synthèse et étude physico-chimique de ligands macrocycliques, macrobicycliques et macrotricycliques dérivés du 5,12-dioxocyclame
2002
The synthesis and the physico-chemical studies of macropolycyclic ligands based on 5,12-dioxocyclam L1 are presented. The first part of this dissertation presents the structural and physico-chemical properties of L1 and its N-substituted derivatives L2 and L3. A potentiometric study reveald a cooperative protonation of the two macrocyclic ligands L1 and L2 whereas the study of the macrotricycle L3 in a methanol-water mixture revealed a sequential cooperative diprotonation of the four tertiary amines. The square planar nickel and copper complexes were synthesized and characterized using infrared, UV-vis and ESR spectgroscopy. The spectroscopic studies showed the presence of intermolecular hy…
Amber Particles as Living Plant Cell Markers in Flow Cytometry / Dzintara Daļiņas Kā Dzīvu Augu Šūnu Marķieri Plūsmas Citometrijā
2015
Abstract The unique biological properties of amber are well known. Amber particles that penetrate into the cellular matrix can potentially be used as markers of plant cell biological activity by identification of living cells in flow cytometry. However, there have been no studies on effect of amber particles on plant cells. The aim of this study was to determine effect of amber nano- and micro- (5 nm-3 μm) particles on somatic and gametic cells and to assess the possibility to use amber particles as alive plant cells markers. To reach the aim, fluorescence of cells was determined in the presence of amber particles, and amber components - spirit of amber and sodium succinate dibasic hexahydr…
Azonia spiro polyaza macrocycles containing biphenyl subunits as anion and cation receptors
2011
Abstract The reaction of N-Boc triprotected cyclam with bis(chloromethyl)biphenyl followed by the corresponding deprotection of the nitrogen atoms allows the preparation of receptor 3 containing an azonia spiro subunit. This receptor shows slightly increased basicity than cyclam, in particular for the formation of the appropriate triply charged species as a consequence of the reduced capacity of the structure present in 3 to stabilize the species with lower protonation degrees through the formation of intramolecular hydrogen bonds. The properties of 3 as a receptor for Cu2+ and Zn2+ and the anions derived from PO 4 3 − ( Pi ) , P 2 O 7 4 − ( PPi ) , P 3 O 10 5 − ( TPP ) and ATP have been st…
An Off-On-Off Fluorescent Sensor for pH Windows Based on the 13aneN4-Zn 2+ System
2016
International audience; The new ligand L was prepared and features a 13-membered tetraaza macrocyclic ring with a 1,8-naphthalimide fluorophore appended to a C atom of its backbone. The protonation constants of L as well as its complexation constants with Zn2+ ions were determined in 1:1 water/methanol solutions by potentiometric titrations. Fluorimetric pH titrations were performed with L alone and L in the presence of Zn2+ ions (1:1), and the species distributions (%) versus pH were compared. A window-shaped fluorescence trend was observed with pH for the L/Zn2+ system, which behaves as an off-on-off pH sensor. The on window is centred in the 6.5-7.5 pH range, in correspondence with the f…
Fusariose du cyclamen : vers un outil de détection précoce
2016
SPEIPM; Fusariose du cyclamen : vers un outil de détection précoce
Isolement et caractérisation de saponosides extraits de deux plantes médicinales : Cyclamen africanum, Zygophyllum cornutum et évalution de leur acti…
2014
The appearance of several diseases, such as cancer, diabetes, high blood pressure and spread of infections mutagenic virus type can be linked to the quality and lifestyle that we lead today. Indeed, several studies on the factors triggering these so-called "morbid" long-or short-term illnesses are related to stress and quality of food consumed, whether of plant and animal origin. These diseases are becoming a common occurrence, they affect different races and all classes of society. According ethnobotanical research, naturally occurring substances, allowed civilizations to survive deadly diseases. For example, we thus find references to periods of malarial fever in China and one of the symp…