X‐ray Crystal Structure and Characterization in Aqueous Solution of{<i>N</i>,<i>N</i>′‐Ethylenebis(pyridoxylaminato)}zinc(<scp>II</scp>)

Correia, Isabel; Dörnyei, Ágnes; Avecilla, Fernando; Kiss, Tamás; Pessoa, João Costa

doi:10.1002/ejic.200500623

Cited by 26 publications

(15 citation statements)

References 30 publications

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“…In this perspective, metal complexes derived from pyridoxal are relevant for a global understanding of the mechanism of action of pyridoxal in vivo , and for developing novel bioactive compounds for therapeutic use such as anticancer agents. Several complexes of ligands derived from pyridoxal have been reported . In the presence of metal ions, pyridoxal can catalyze important metabolic reactions, such as transamination, decarboxylation and racemization of amino acids .…”

Section: Introductionmentioning

confidence: 99%

Tin(IV) Schiff base complexes derived from pyridoxal: Synthesis, spectroscopic properties and cytotoxicity

Galván-Hidalgo

Chans

Ramírez‐Ápan

et al. 2017

Applied Organom Chemis

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The synthesis of monomeric pentacoordinated diorganotin(IV) complexes derived from pyridoxal hydrochloride and 4-or 5-R-substituted ortho-aminophenols is described. The complexes were characterized using UV-visible, infrared, mass, 1 H NMR, 13 C NMR and 119 Sn NMR spectral techniques. The molecular structure of three complexes was established using X-ray diffraction: 3b and 3d show a distorted trigonal bipyramidal geometry, in which the basal plane is defined by the butyl groups and the iminic nitrogen atom, whereas the oxygen atoms from the aromatic ring occupy axial positions; in contrast, complex 3e exhibits a square pyramidal geometry. The cytotoxic activity of all complexes against human cell lines U-251 (glioblastoma), K-562 (chronic myelogenous leukemia), HCT-15 (human colorectal cancer), MCF-7 (human breast cancer) and SKLU-1 (non-small-cell lung cancer) was evaluated, and the inhibitory percentage values indicated higher activity than the reference standard, cisplatin. Acute toxicity studies were performed in vivo for the prepared complexes to determine the lethal medium dose (LD 50 ) after intraperitoneal administration to mice.

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Section: Introductionmentioning

confidence: 99%

Tin(IV) Schiff base complexes derived from pyridoxal: Synthesis, spectroscopic properties and cytotoxicity

Galván-Hidalgo

Chans

Ramírez‐Ápan

et al. 2017

Applied Organom Chemis

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“…[4][5][6][7][8] precursors or by the reaction of the selected diamine with a 2,4-disubstituted phenol and formaldehyde in a modified Mannich reaction. [9] This class of ligands and their metal complexes present much higher resistance to hydrolysis than their salen counterparts, [10][11][12][13] which is very important when using a "green" solvent such as water or ionic liquids and/or a "green" oxidant such as aqueous hydrogen peroxide, or when anchored to cross-linked polystyrene.…”

Section: Introductionmentioning

confidence: 99%

Titanium(IV)–Salan Catalysts for Asymmetric Sulfoxidation with Hydrogen Peroxide

Adão¹,

Avecilla

Bonchio

et al. 2010

Eur J Inorg Chem

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We report the synthesis and the solution and solid-phase characterization of several titanium(IV)–salan complexes. The structures of the ligands H2sal(R,R-chan), H2ovan(S,S-chan), and H6pyr(R,R-chan)4+·4Cl–·H2O were determined by single-crystal X-ray diffraction and their main features are compared and discussed. Single crystals suitable for X-ray diffraction studies were also obtained for [Ti4{sal(R,R-chan)}4(μ-O)4] and showed a tetranuclear core bearing μ-oxo bridges between the titanium atoms and the ligand wrapped around the Ti in a fac-mer geometry. The Ti–salan complexes were tested as catalysts in the benchmark oxidation of thioanisole with H2O2 as oxidant in organic solvents. High H2O2 conversion and moderate enantioselectivities (up to 51 % ee) were obtained. In an effort to perform greener catalysis the complexes were tested in selected ionic liquids with several oxidants. [Ti{5-MeO-sal(R,R-chan)}] was also covalently bound to a polystyrene matrix. tert-Butyl hydroperoxide was found to be the most suitable oxidant for use in ionic liquids (100 % conversion vs. 80 % with H2O2) and in general the Ti–salan complexes showed better activity in ILs at 25 °C although with reduced induced asymmetry (up to 18 % ee)

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“…Our group has been studying salan complexes for several years [8,9,17,18]. We reported studies on the solution speciation of salan-type ligands with V IV and V V , Cu II , Ni II , and Zn II .…”

Section: Introductionmentioning

confidence: 99%

Vanadium-salen and -salan complexes: Characterization and application in oxygen-transfer reactions

Adão¹,

Maurya

Kumar

et al. 2009

Pure and Applied Chemistry

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Salen complexes are a versatile and standard system in oxidation catalysis. Their reduced derivatives, called salan, share their versatility but are still widely unexplored. We report the synthesis of a group of new vanadium-salen and -salan complexes, their characterization and application in the oxidation of simple organic molecules with H 2 O 2 . The ligands are derived from pyridoxal and chiral diamines (1,2-diaminocyclohexane and 1,2-diphenylethylenediamine) and were easily obtained in high yields. The V IV complexes were prepared and characterized in the solid state (Fourier transform infrared, FTIR, and magnetic properties) and in solution by spectroscopic techniques: UV-vis, circular dichroism (CD), electron paramagnetic resonance (EPR), and 51 V NMR, which provide information on the coordination geometry. Single crystals suitable for X-ray diffraction studies were obtained from solutions containing the V IV -pyr(S,S-chan) complex: [V V O{pyr(S,Schen)}] 2 (μ-O) 2 ؒ2(CH 3 ) 2 NCHO, where the ligand is the "half" Schiff base formed by pyridoxal and 1S,2S-diaminocyclohexane. The dinuclear species shows a OV V (μ-O) 2 V V O unit with tridentate ligands and two μ-oxo bridges. The V IV complexes of the salan-type ligands oxidize in organic solvents to a V V species, and the process was studied by spectroscopic techniques. The complexes were tested as catalysts in the oxidation of styrene, cyclohexene, and cumene with H 2 O 2 as oxidant. Overall, the V-salan complexes show higher activity than the parent V-salen complexes and are an alternative ligand system for oxidation catalysis.

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X‐ray Crystal Structure and Characterization in Aqueous Solution of{N,N′‐Ethylenebis(pyridoxylaminato)}zinc(II)

Cited by 26 publications

References 30 publications

Tin(IV) Schiff base complexes derived from pyridoxal: Synthesis, spectroscopic properties and cytotoxicity

Tin(IV) Schiff base complexes derived from pyridoxal: Synthesis, spectroscopic properties and cytotoxicity

Titanium(IV)–Salan Catalysts for Asymmetric Sulfoxidation with Hydrogen Peroxide

Vanadium-salen and -salan complexes: Characterization and application in oxygen-transfer reactions

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