نتایج جستجو برای: salen complexes
تعداد نتایج: 137585 فیلتر نتایج به سال:
The design and the synthesis of chiral macrocycles acting as enantioselective receptors is of great interest in the field of enzyme mimicking enantioselective catalysis as well as in that of racemic resolution and of chiral sensing. Recently particular attention has been devoted to neutral ditopic receptors able to simultaneously bind chiral ammonium cations and their counteranions. In this wor...
The electroactivity of zeolite-encapsulated redox-active transition metal complexes, {M(L)}Z, was explored for Co(salen) and [Fe(bpy)3] formed in NaY zeolite (where salen ) N,N′-bis(salicylidene)ethylenediamine and bpy ) 2,2′-bipyridine). The zeolite boundary was characterized via X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry in nonaqueous electrolyte at either zeolite-modified ...
A series of cationic ruthenium(VI) nitrido species containing the cyclohexyl-bridged salen ligand (L) and its derivatives, [RuVI(N)(L)]+, have been prepared by treatment of [NBun4][RuVI(N)Cl4] with H2L in methanol. The structure of [RuVI(N)(L)](ClO4) (1a) has been determined by X-ray crystallography, d(RuN) = 1.592 A. In solvents such as DMF or DMSO, [RuVI(N)(L)]+ undergoes a facile N...N coupl...
The ligand, N,N'-bis(salicylidine)ethylenediamine or salen (L), and its complexes 1-3 with Ni(II), Cu(II) Mn(II) were synthesized. Various analytical methods such as microanalysis, 1H-NMR, 13C-NMR, ESI-MS FT-IR spectroscopy has been used to characterize the synthesized compounds. Antibacterial activity of prepared compounds tested against two Gram-positive bacteria Staphylococcus aureus Bacillu...
BACKGROUND There are many nucleoside metal complexes known. According to observations made, only very few of them reveal their central ion to be co-ordinated by the sugar part of their molecules. The regio- and stereosspecific exchange of the hydroxyl groups at the sugar moiety by chelating units improves its complexation ability and should give access to a new class of chiral ligands. RESULT...
Dimanganese(III) complexes of salen-type ligands anchored by 9,9-dimethylxanthene-4,5-diyl spacers were synthesized. Two types of structures, cyclic and acyclic forms, are presented. The 2 + 2 Schiff-base condensation of 5,5'-(9,9-dimethylxanthene-4,5-diyl)bis(salicylaldehyde) and 1,2-diaminobenzene gave a macrocyclic ligand, from which a cyclic dimanganese(III) complex was synthesized. A simil...
We report the alternating ring-opening copolymerization of dihydrocoumarin with epoxides catalyzed by chromium(III) salen complexes. This process provides access to a range of perfectly alternating polyesters with high molecular weights and narrow molecular weight distributions. Atactic poly(cyclohexene dihydrocoumarate) and poly(cyclopentene dihydrocoumarate) were found to be semi-crystalline ...
An efficient protocol for the selective fluorination of benzylic C-H bonds is described. The process is catalyzed by manganese salen complexes and uses nucleophilic fluorine sources, such as triethylamine trihydrofluoride and KF. Reaction rates are sufficiently high (30 min) to allow adoption for the incorporation of (18)F fluoride sources for PET imaging applications.
Chiral indium salen complexes are highly active, isoselective catalysts for the ring opening polymerization of racemic lactide. The polymerizations are well controlled and polymers with high molecular weights and low molecular weight distributions are obtained. Preliminary kinetic investigations with the enantiopure complex confirm enantiomorphic site control as the dominant contributor to sele...
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