Showing papers on "Schiff base published in 1972"
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TL;DR: The Schiff base, α-N -methyl-S -methyl β-n-β-n -(2-pyridyl)methylendithiocarbazate, C 5 H 4 NCH(Me)C(SMe)S (NNMeS) as discussed by the authors, behaves as a neutral tridentate ligand, forming stable crystalline complexes with first-row transition metal ions.
60 citations
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53 citations
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TL;DR: The synthesis and properties of uranyl complexes with tetradentate ligands of formula UO 2 (saldiamine) are discussed in this article, where electronic and circular dichroism spectra are also discussed.
39 citations
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TL;DR: The pyridoxal-P coenzyme of phosphorylase b showed on excitation at 330 nm a maximal fluorescence emission at 535 nm as mentioned in this paper.
32 citations
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TL;DR: In this paper, the copper-oxygen complex of the Schiff base of pyrrole-2-carboxaldehyde and 3-aminopropanol was prepared, and the structure was solved from Patterson and electron density maps and refined by least-squares methods to a ocnventional R value of 0.076.
31 citations
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TL;DR: In this article, the rate constants for the quenching of triplet states of several molecules by certain Schiff bases and their Ni(II) chelate complexes have been measured using the technique of laser photolysis.
Abstract: Rate constants for the quenching of triplet states of several molecules by certain Schiff bases and their Ni(II) chelate complexes have been measured using the technique of laser photolysis. In the case of the parent ligands the dependence of the quenching efficiency on the energy of the triplet states being quenched suggests triplet–triplet energy transfer as the quenching mechanism and allows estimates of the energies of the triplet states of the ligands which are often too short-lived to be calculated. The observed variation in rate constants for quenching by diamagnetic trans-planar Schiff base Ni(II) complexes is also explained as being due to triplet–triplet energy transfer with high energy triplet donors exciting triplet ligand states and low energy donors exciting triplet ligand field states in the quencher. It is suggested that the much lower efficiency of quenching by paramagnetic, tetrahedral and octahedral Ni(II) complexes of low energy triplet donors is due to the stereochemical changes and demonstrates the need for good overlap with d orbitals before spin-allowed exchange transfer of high efficiency can occur to lower lying ligand field states in coordination complexes.
29 citations
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TL;DR: In this paper, mixed-ligand chelate complexes of cobalt(111) of the type (β-diketone)Co(salen) have been synthesized using replacement reactions of the coba1t (111) species XCo(Salen) (X = halogen, alkyl group; salen = tetradentate Schiff-base ligand) by the appropriate β-dikaetone, or its sodium or thallium(1) salt.
Abstract: Mixed-ligand chelate complexes of cobalt(111) of the type (β-diketone)Co(salen) have been synthesized using replacement reactions of the coba1t(111) species XCo(salen) (X = halogen, alkyl group; salen = tetradentate Schiff-base ligand) by the appropriate β-diketone, or its sodium or thallium(1) salt. Studies of their infrared, N.M.R.,and mass spectra point to the formation of cis oxygen-bonded β-diketone chelates, in which the salen group adopts an unusual twisted configuration.
22 citations
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21 citations
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TL;DR: The Schiff base, 2-(2,3-diaza-4-methylthio-5-thiahexa-1, 3-dienyl) pyridine, C 5 H 4 NCHNNC(SMe) 2 (NNSMe), with bidentate NN-bonded ligand is probably halogenbridged and six-coordinate as discussed by the authors.
21 citations
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TL;DR: In this paper, the Schiff base ligands studied have aromatic and nonaromatic nitrogen donor atoms, which differ from most other ligands used for the catalytic enhancement of metals in nonaqueous systems.
20 citations
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TL;DR: In this paper, metal-ion-induced rearrangement of 2,6-bis-(2-methyl-2-benzothiazolinyl)pyridine yields five-coordinate zinc and cadmium complexes of the corresponding Schiff base; the X-ray structure of the zinc complex shows that the coordinated ligand has a novel helical configuration.
Abstract: Metal-ion-induced rearrangement of 2,6-bis-(2-methyl-2-benzothiazolinyl)pyridine yields five-co-ordinate zinc and cadmium complexes of the corresponding Schiff base; the X-ray structure of the zinc complex shows that the co-ordinated ligand has a novel helical configuration.
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TL;DR: The Schiff base α-N-methyl-S-methylβ-N-(6-methylpyrid-2-yl)methylendithiocarbazate, 6-MeC5H3NCHNN(Me)C(SMe)S(MeNNMeS)2] as discussed by the authors, which acts as a tridentate ligand and forms stable, crystalline complexes with iron(II), cobalt (II), nickel(II) and copper(II).
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TL;DR: Some Co(Schiff base)NO complexes, as well as [Co(en)2NO]2+, react with oxygen in solutions containing a base or in co-ordinating solvents to yield the corresponding nitro-complexes; kinetic studies show that the rates of reaction increase with increasing basicity of the added base as discussed by the authors.
Abstract: Some Co(Schiff base)NO complexes, as well as [Co(en)2NO]2+, react with oxygen in solutions containing a base or in co-ordinating solvents to yield the corresponding nitro-complexes; kinetic studies show that the rates of reaction increase with increasing basicity of the added base.
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TL;DR: In this paper, the copper(II) and oxovanadium(IV) complexes of a new Schiff base derived from heptane-2,4,6-trione and ethylenediamine were prepared.
Abstract: The copper(II) and oxovanadium(IV) complexes of a new Schiff base derived from heptane-2,4,6-trione and ethylenediamine were prepared. Of a macrocyclic two-to-two and an open jaw-shaped two-to-one (trione to diamine) condensation product, only the latter gave mononuclear copper (II) and oxovanadium(IV) complexes. The coordinating sites to the metal ion in each complex are discussed referring to the spectroscopic results.
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16 Aug 1972TL;DR: In this paper, an optically active alkyl chrysanthemate was produced by reacting 2,5-dimethyl-2,4-hexadiene with an alkyyl diazoacetate in the presence of a copper complex coordinated with a particular Schiff base.
Abstract: Process for producing an optically active alkyl chrysanthemate by reacting 2,5-dimethyl-2,4-hexadiene with an alkyl diazoacetate in the presence of a copper complex coordinated with a particular Schiff base.
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TL;DR: In this article, a series of derivatives of the general formula R-RhSalenPy (R=CH 3, C 2 H 5, n-C 3 CO, CH 2 CHCH 2 and C 6 H 5 CH 2 ) have been derived using both 0.2% sodium amalgam and NaBH 4 /PdCl 2.
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TL;DR: In this article, the π-allyl group is represented as a bridge between two allylpalladium units, and the 1H NMR spectra of these complexes have enabled isomeric forms of several of the compounds to be detected and provided information about their dynamic stereochemistry.
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TL;DR: In this article, the authors investigated the kinetics of reaction of Fe(bipy)2(CN)2 with 1,10-phenanthroline in water and in mixed aqueous solvents.
Abstract: The kinetics of reaction of Fe(bipy)2(CN)2 with 1,10-phenanthroline have been investigated in water and in mixed aqueous solvents. Logarithms of rate constants for this reaction, and for the analogous reaction of a Schiff base complex Fe(SB)2(CN)2, where SB =N-(2-pyridylmethylene)-3,4-dimethylaniline, correlate linearly with Grunwald–Winstein solvent Y values. Reaction of Fe(bipy)2(CN)2 with hydroxide follows a first-order rate law with rates independent of hydroxide concentration.
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TL;DR: The copper complex of the ONS Schiff base of 5-nitrosalicylaldehyde and S-methyl dithiocarbazate is ferromagnetic and probably exists as a tetrahedral cluster, while the copper complexes of some other similar Schiff bases are antiferromagnetic as mentioned in this paper.
Abstract: The copper complex of the ONS Schiff base of 5-nitrosalicylaldehyde and S-methyl dithiocarbazate is ferromagnetic and probably exists as a tetrahedral cluster, while the copper complexes of some other similar Schiff bases are antiferromagnetic.
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TL;DR: In this paper, the cyclic Schiff base 10, which constitutes an intermediate in this reaction, was prepared by reduction of 9 with CrCl2 and was further reduced to 8 with zinc/acetic acid.
Abstract: 3-Isopropyl-4-thia-2,6-diazabicyclo[3.2.0]heptan-7-on (8), a potential intermediate for the synthesis of new β-lactam antibiotics [5], was prepared from the urethanes 7a and 9 by reduction with zinc/acetic acid. The cyclic Schiff base 10, which constitutes an intermediate in this reaction, was prepared by reduction of 9 with CrCl2 and was further reduced to 8 with zinc/acetic acid.
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TL;DR: The reaction of cyclohexanone enamines with benzylidenaniline in acetic acid gave unexpected N-phenyldecahydroacridine derivatives as mentioned in this paper.
Abstract: The reaction of cyclohexanone enamines with benzylidenaniline in acetic acid gave unexpected N-phenyldecahydroacridine derivatives. The formation of these compounds can be rationalized assuming the [2+2]cycloaddition between enamines and the Schiff base to form an azetidine at the initial stage.
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TL;DR: DecDecomposition of N(2-pyridyl-methylene) 4-methyl-aniline with E.D.A. gives a convenient route to the parent Schiff base.
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TL;DR: The dianionic tricyclic quadridentate Schiff base ligands derived from 2-pyridylhydrazine and 1,2-diones form dimeric nickel(II) and palladium(II), which apparently have a significant metal-metal bonding interaction, and which may be readily oxidised as mentioned in this paper.
Abstract: The dianionic tricyclic quadridentate Schiff base ligands derived from 2-pyridylhydrazine and 1,2-diones form dimeric nickel(II) and palladium(II) species of a novel type, which apparently have a significant metal–metal bonding interaction, and which may be readily oxidised.
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TL;DR: Treatment of the p-nitrobenzaldehyde Schiff base of 6-APA benzyl ester with phenyl-lithium and then with oxygen affords the 6,6′-dimer (IV) and the nitrone (X) as discussed by the authors.
Abstract: Treatment of the p-nitrobenzaldehyde Schiff base of 6-APA benzyl ester (I) with phenyl-lithium and then with oxygen affords the 6,6′-dimer (IV) and the nitrone (X).