Metal-ion-controlled transamination in the synthesis of macrocyclic Schiff-base ligands. Part 1. Reactions of 2,6-diacetylpyridine and dicarbonyl compounds with 3,6-dioxaoctane-1,8-diamine

Author(s):  
S. Martin Nelson ◽  
C. Victor Knox ◽  
Malachy McCann ◽  
Michael G. B. Drew
2018 ◽  
Vol 4 (4) ◽  
pp. 51 ◽  
Author(s):  
Monotosh Mondal ◽  
Maharudra Chakraborty ◽  
Michael G. B. Drew ◽  
Ashutosh Ghosh

Three trinuclear Ni(II)-Na(I) complexes,[Ni2(L1)2NaCl3(H2O)]·H2O (1), [Ni2(L2)2NaCl3(H2O)] (2), and [Ni2(L3)2NaCl3(OC4H10)] (3) have been synthesized using three different NNO donor tridentate reduced Schiff base ligands, HL1= 2-[(3-methylamino-propylamino)-methyl]-phenol, HL2= 2-[(3-methylamino-propylamino)-methyl]-4-chloro-phenol, and HL3= 2-[(3-methylamino-propylamino)-methyl]-6-methoxy-phenol that had been structurally characterized. Among these complexes, 1 and 2 are isostructural in which dinuclearNi(II) units act as metalloligands to bind Na(I) ions via phenoxido and chlorido bridges. The Na(I) atom is five-coordinated, and the Ni(II) atom possesses hexacordinated distorted octahedral geometry. In contrast, in complex 3, two -OMe groups from the dinuclear Ni(II) unit also coordinate to Na(I) to make its geometry heptacordinated pentagonal bipyramidal. The magnetic measurements of complexes 1–3 indicate ferromagnetic interactions between dimeric Ni(II) units with J = 3.97 cm−1, 4.66 cm−1, and 5.50 cm−1for 1–3, respectively, as is expected from their low phenoxido bridging angles (89.32°, 89.39°, and 87.32° for 1–3, respectively). The J values have been calculated by broken symmetry DFT method and found to be in good agreement with the experimental values.


2010 ◽  
Vol 39 (22) ◽  
pp. 5332 ◽  
Author(s):  
Edwin C. Constable ◽  
Guoqi Zhang ◽  
Catherine E. Housecroft ◽  
Jennifer A. Zampese

Author(s):  
Dharmendra Kumar Sahu ◽  
Shekhar Srivastava

Ninety Cr(III) macrocyclic Schiff base complexes of the type [CrL_n^(1-10) X_2 ]X(Where X = Cl- or NO-3 or CH3COO- and = macrocyclic Schiff base ligands derived from condensation of trimesic acid or p-phthalic acid or squaric acid with different aliphatic diamines) have been synthesised and characterised by elemental analysis; molar conductance; electronic spectra; IR; magnetic moment and XPS i.e. X-ray Photoelectron spectra data. An octahedral geometry was established for them.


Author(s):  
AMAL M ALOSAIMI ◽  
INES EL MANNOUBI ◽  
SAMI A ZABIN

Objective: This work aimed at synthesizing tridentates asymmetrical Schiff base ligands containing sulfur atom and using them for preparing metal complexes with the iron triad metals. The prepared compounds were assayed in vitro for antimicrobial potential and in vivo molluscicidal activity. Methods: The unsymmetrical tridentate Schiff bases (SL1, SL2, and SL3) were prepared using 2-aminothiophenol as primary amine and condensed with 2-carboxybenzaldehyde, 2-hydroxy-1-naphthaldehyde, and 7-formyl-8-hydroxyquinoline. These ligands were used in preparing metal complexes with iron triad metals. The synthesized Schiff base ligands and their corresponding metal complexes were characterized and their proposed structures were confirmed using different physical and spectroscopic analytical techniques. All ligands and their corresponding metal complexes were assayed against different bacterial and fungal strains using the agar disk-diffusion technique. The molluscicidal activity was performed according to the standard reported methods as cited in the literature and by observing the toxicity and lethal dose according to the WHO guidelines. Results: The synthesized ligands behave as tridentate (NOS) ligands and form mononuclear complexes with the general formula [M(SL)2] with an octahedral geometry around the central metal ion. Metal complexes were non-electrolytic in nature. The in vitro antibacterial and antifungal examination results showed weak activity of the ligands, and there was enhanced activity with the complexes. The in vivo molluscicidal activity of the tested compounds showed good activity. Conclusion: The targeted compounds were prepared successfully, characterized, and showed some biological activity but lower than the standard reference drugs.


ChemInform ◽  
2004 ◽  
Vol 35 (48) ◽  
Author(s):  
R. Hernandez-Molina ◽  
A. Mederos

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