Schiff base equilibria. VI. n- and t-Butylimines of pyridine-2-aldehyde

1968 ◽  
Vol 21 (10) ◽  
pp. 2427 ◽  
Author(s):  
RW Green ◽  
MJ Rogerson
Keyword(s):  
Schiff Base ◽  
Schiff Bases ◽  
Formation Constant ◽  
Equilibrium Constants

Equilibrium constants at 25� have been measured for the formation of Schiff bases of pyridine-2-aldehyde with n-butylamine (1.45 x 108) and t-butylamine (93). The Schiff base of salicylaldehyde with t-butylamine has a formation constant 9.1 x 108 and pK 13.0.

scholarly journals Schiff base equilibria. VII. Formation and distribution of N-(β-Hydroxyethyl)salicylideneimine

1969 ◽  
Vol 22 (5) ◽  
pp. 917 ◽  
Author(s):  
RW Green ◽  
RJ Sleet
Keyword(s):  
Aqueous Solution ◽  
Schiff Base ◽  
Formation Constant ◽  
Equilibrium Constants

The formation constant and pK of the Schiff base N-(8- hydroxyethyl)salicylideneimine in aqueous solution at 25� have been determined spectrophotometrically to be 5.01 x 103 and 11.4 respectively. These equilibrium constants have been used to account for the distribution of the imine between water and chloroform.

Equilibrium constants of pyridoxal 5'-phosphate Schiff bases - A polarographic study

1983 ◽  
Vol 48 (7) ◽  
pp. 1950-1955 ◽  
Author(s):  
Juan Llor ◽  
Javier Bonal ◽  
Manuel Cortijo
Keyword(s):  
Schiff Base ◽  
Ionic Strength ◽  
Equilibrium Constant ◽  
Schiff Bases ◽  
Ph Dependence ◽  
Equilibrium Constants ◽  
Constant Ionic Strength ◽  
Polarographic Study ◽  
Ionic Forms

The equilibrium constant for the formation of the Schiff base between pyridoxal 5'-phosphate and n-hexylamine has been evaluated from polarographic measurements. The pH dependence of the equilibrium constant has been investigated at constant ionic strength. The values thus obtained for the equilibrium constant compare well with those computed from the pK of the several ionic forms of pyridoxal 5'-phosphate, its Schiff base and the amine present in the solution.

scholarly journals Synthesis and Evaluation of Schiff Bases of 4-Amino-5-(chlorine substituted phenyl)-4H-1,2,4-triazole-3-thione as Antimicrobial Agents

2020 ◽  
Vol 41 (1) ◽  
pp. 26-35
Author(s):  
Kishor Devkota ◽  
Govinda Pathak ◽  
Bhushan Shakya
Keyword(s):  
Schiff Base ◽  
Schiff Bases ◽  
Antimicrobial Agents ◽  
Triazole Ring ◽  
Antimicrobial Activities ◽  
Biologically Active ◽  
Spectral Techniques ◽  
Schiff Base Derivatives ◽  
Bacteria And Fungi ◽  
Different Strains

Triazole ring system has attracted a continuously growing interest of synthetic organic chemists and those dealing with the medicinal compounds due to its versatile potential to interact with biological systems. Schiff bases are also considered as one of the most biologically active compounds.  The aim of the present study was to synthesize new Schiff bases bearing triazole nucleus and to assess their antimicrobial activities. Four new Schiff base derivatives of 1,2,4-triazole-3-thione were synthesized by combining two different pharmacophores viz. triazole nucleus and Schiff base moiety and were characterized by spectral techniques (UV, FT-IR, and NMR). The Schiff bases were evaluated for antibacterial (Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae) and antifungal (Candida albicans) activities. The synthesized compounds exhibited good to moderate activities against different strains of bacteria and fungi tested.

Syntheses, Spectroscopy And Crystal Structures Of (R)-N-(1-Aryl-Ethyl)Salicylaldimines And [Rh{(R)-N-(1-Aryl-Ethyl)Salicylaldiminato}(η4-Cod)] Complexes

2007 ◽  
Vol 62 (6) ◽  
pp. 807-817 ◽  
Author(s):  
Mohammed Enamullah ◽  
A.K.M. Royhan Uddin ◽  
Anne-Christine Chamayou ◽  
Christoph Janiak
Keyword(s):  
Mass Spectrometry ◽  
Schiff Base ◽  
Schiff Bases ◽  
Structure Determination ◽  
Chelate Ring ◽  
Optical Rotation ◽  
X Ray ◽  
Mononuclear Complexes ◽  
Chiral Schiff Base ◽  
C Nmr

Condensation of salicylaldehyde with enantiopure (R)-(1-aryl-ethyl)amines yields the enantiopure Schiff bases (R)-N-(1-aryl-ethyl)salicylaldimine (HSB*; aryl = phenyl, 2-methoxyphenyl, 3- methoxyphenyl, 4-methoxyphenyl (4), 4-bromophenyl (5), 2-naphthyl). These Schiff bases readily react with dinuclear (acetato)(η4-cycloocta-1,5-diene)rhodium(I), [Rh(μ-O2CMe)(η4-cod)]2, to afford the mononuclear complexes, cyclooctadiene-((R)-N-(1-aryl-ethyl)salicylaldiminato-κ2N,O)- rhodium(I), [Rh(SB∗)(η4-cod)] (SB* = deprotonated chiral Schiff base = salicylaldiminate; aryl = phenyl (7), 2-methoxyphenyl, 4-methoxyphenyl, 4-bromophenyl, 2-naphthyl). The complexes have been characterized by IR, UV/vis, 1H/13C NMR and mass spectrometry, optical rotation as well as by single-crystal X-ray structure determination for 4, 5 and 7. The structure of 5 shows C-Br· · ·π contacts. Compound 7 is only the second example of a Rh(η4-cod) complex with a six-membered Rh-N,O-chelate ring

Notizen: Magnetic Studies on Schiff Base Complexes of Al(III) and Si(IV)

1974 ◽  
Vol 29 (7-8) ◽  
pp. 565-566 ◽  
Author(s):  
R. N. Prasad ◽  
J. P. Tandon
Keyword(s):  
Schiff Base ◽  
Schiff Bases ◽  
Schiff Base Complexes ◽  
Magnetic Studies ◽  
Magnetic Susceptibilities

The magnetic susceptibilities of some newly syntesized Al(III) and Si(IV) complexes of Schiff bases derived from the condensation of o-hydroxyacetophenone or 2-dydroxy-1-naphthaldehyde with hydroxyalkylamines or diamines have been measured and the data indicate their diamagnetic character.

Polarimetric and nuclear magnetic resonance studies of the complexation of mercury by thiols

1988 ◽  
Vol 66 (12) ◽  
pp. 3184-3189 ◽  
Author(s):  
Mohamed M. Shoukry ◽  
Bruce V. Cheesman ◽  
Dallas L. Rabenstein
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Formation Constant ◽  
Ph Dependence ◽  
Equilibrium Constants ◽  
Rotatory Power ◽  
Acid Dissociation ◽  
Optical Rotatory ◽  
Optical Rotatory Power ◽  
Nuclear Magnetic

The complexation of Hg(II) by glutathione has been studied by polarimetry under conditions of excess ligand with the objective of characterizing formation of the 3:1 complex, Hg(glutathione)3. The optical rotatory power of solutions containing glutathione only and of solutions containing glutathione and Hg(II) at ratios of 2:1, 2.5:1, 3:1, and 4:1 was measured as a function of pH. Acid dissociation constants for the ammonium and thiol groups of glutathione and for the two ammonium groups of Hg(glutathione)2 and the formation constant of the 3:1 complex (Hg(glutathione)2 + glutathione [Formula: see text] Hg(glutathione)3) were determined from the pH dependence of the optical rotatory power. The value obtained for the formation constant, Kf = 1.5 × 103, indicates that binding of the third ligand to form Hg(glutathione)3 is much weaker than binding of the first two glutathione ligands. However, calculations indicate that binding is sufficiently strong that a significant fraction of Hg(II) is present as Hg(glutathione)3 under physiological conditions. Equilibrium constants were also determined by polarimetry and by 13C nuclear magnetic resonance for the displacement of one thiolate ligand by another (RSHgSR + R′SH [Formula: see text] RSHgSR′ + RSH; RSHgSR′ + R′SH [Formula: see text] R′SHgSR′ + RSH). The results indicate that, at pH 5.5 and at physiological pH, the relative stability increases in the order Hg(glutathione)2 < Hg(penicillamine)2 < Hg(mercaptoethylamine) 2. However, when competitive protonation of free ligand is accounted for, it is shown that the intrinsic stability of the complexes increases in the order Hg(penicillamine)2 < Hg(mercaptoethylamine)2 < Hg(glutathione)2, which parallels the order of the Brønsted basicity of the thiolate ligands.

Schiff Bases and Related Substances. III. Acetylation of a Schiff Base-Thiol Adduct1

1958 ◽  
Vol 80 (13) ◽  
pp. 3475-3478 ◽  
Author(s):  
Gardner W. Stacy ◽  
Richard I. Day ◽  
Richard J. Morath
Keyword(s):  
Schiff Base ◽  
Schiff Bases ◽  
Related Substances

Electronic Structure of Pseudotetrahedral Copper(II) Schiff Base Complexes

1977 ◽  
Vol 32 (5) ◽  
pp. 551-561 ◽  
Author(s):  
John R. Wasson ◽  
H. Wayne Richardson ◽  
William E. Hatfield
Keyword(s):  
Electronic Structure ◽  
Schiff Base ◽  
Schiff Bases ◽  
Opposite Direction ◽  
Hyperfine Coupling ◽  
Coupling Constants ◽  
Schiff Base Complexes ◽  
Hyperfine Coupling Constants ◽  
Structure Correlations

Copper(II) complexes with the Schiff bases formed by condensing t-butyl-, isopropyl-, cyclohexyl- and diphenylmethylamines with salicylaldehyde and 3-methoxy- and 5-nitrosalicyl-aldehyde have been prepared and characterized. The isotropic nuclear hyperfine coupling constants increase in the order t-butyl &lt; isopropyl &lt; cyclohexyl &lt; diphenylmethyl for the N-substituents in the three series of complexes while isotropic g-values increased in the opposite direction. Spectra structure correlations were examined and discussed.

scholarly journals A novel approach toward the synthesis of some new tridentate Schiff bases from anil-like compounds

2016 ◽  
Vol 81 (10) ◽  
pp. 1111-1119 ◽  
Author(s):  
Fatemeh Bagheri ◽  
Abolfazl Olyaei
Keyword(s):  
Schiff Base ◽  
Formic Acid ◽  
Schiff Bases ◽  
Condensation Product ◽  
Reaction Times ◽  
Acid Catalyst ◽  
Schiff Base Ligands ◽  
Novel Approach ◽  
Solvent Free Conditions ◽  
Novel Method

A novel method was developed for synthesizing a series of new three dentate Schiff base ligands starting from hydroxynaphthalidene pyrimidinyl amines with o-phenylenediamines or o-aminophenol or 2-amino-3-hydroxy-pyri-dine in the presence of formic acid catalyst under solvent-free conditions. In these reactions [1+1] condensation product as half-unit ligand was obtained. Moreover, the reaction of hydroxynaphthalidene pyrimidinyl amines with 3,4-diamino-pyridine and 1,8-naphthalenediamine lead to the formation of C2-naphthylated imidazopyridine and dihydropyrimidine, respectively. The attractive features of this protocol are: use of inexpensive catalyst, operationally simple, short reaction times, easy handling, and good yields.

Phosphine-assisted C–H bond activation in Schiff bases and formation of novel organo cobalt complexes bearing Schiff base ligands

2018 ◽  
Vol 42 (6) ◽  
pp. 4646-4652 ◽  
Author(s):  
Hua Zhang ◽  
Junyang Xing ◽  
Yanhong Dong ◽  
Shangqing Xie ◽  
Shishuai Ren ◽  
...  
Keyword(s):  
Schiff Base ◽  
Schiff Bases ◽  
Bond Activation ◽  
Cobalt Complexes ◽  
Schiff Base Ligands

The sp2 C–H bond activation of the HCN moiety in diphenylphosphino benzalimines was realized using CoMe(PMe3)4 with the elimination of methane.

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