Carboxylic Esters as Ligands. II. Transition metal complexes of Diethyl Acetonedicarboxylate, Ethyl Acetoacetate, and Diethyl oxaloacetate

1967 ◽  
Vol 20 (9) ◽  
pp. 1829 ◽  
Author(s):  
RW Hay ◽  
BP Caughley

The preparation, infrared spectra, magnetic data, and reactions of a variety of transition metal complexes of diethyl acetonedicarboxylate are described. The infrared spectra indicate chelate ring formation with a metal-oxygen bond with the carbonyl group of the ester. Transesterification reactions with alcohols occur much less readily with these complexes than with the corresponding metal oxaloacetates. Bis(ethyl acetoacetato)copper(II) undergoes methanolysis rather than trans-esterification on refluxing with methanol to give a bright blue methoxy-bridged polymer with an abnormally low magnetic moment (μeff 1.14 B.M. at 17�), presumably indicating metal-metal interaction. The magnetic moments of various transition metal complexes of ethyl acetoacetate and diethyl oxaloacetate have also been determined. The β-keto esters have been condensed with 1,2-diaminoethane to give N,N?-bis Schiff bases which exist predominantly as the enamine tautomer in the solid state and in solution. Attempts to prepare copper(II) complexes of these Schiff bases in aqueous ethanol have been unsuccessful as the ligands rapidly hydrolyse in the presence of copper(II) ions.

2021 ◽  
Vol 33 (11) ◽  
pp. 2746-2754
Author(s):  
N.R. Suja ◽  
T.K. Bindu Sharmila ◽  
S.R. Amrutha

Transition metal complexes are known to be efficient catalyst for many organic transformations. Encapsulation of metal complexes in zeolite cage brings many significant modifications in the structure of the metal complexes, which are very interesting from the catalytic point of view. This study aims in a comparative evaluation of the influence of structure of neat and encapsulated complexes in their catalytic activity. Phenol is one of the major industrial pollutants. Heterogenizing transition metal Schiff bases by encapsulation inside the zeolite would help to minimize the reuse problem of transition metal complexes. This article deals with the synthesis, characterization and catalytic activity studies of Co(II), Ni(II) and Cu(II) complexes of 3-hydroxyquinoxaline-2-carboxaldehyde with ethylenediamine (L1) and an o-phenylene diamine (L2).


2002 ◽  
Vol 2 (12) ◽  
pp. 797-799 ◽  
Author(s):  
M. Saidul Islam . ◽  
M. Akhter Farooque . ◽  
M.A.K. Bodruddoza . ◽  
M. Ashik Mosaddik . ◽  
M. Shahidul Alam .

2011 ◽  
Vol 76 (1) ◽  
pp. 75-83 ◽  
Author(s):  
A.S. Ramasubramanian ◽  
Ramachandra Bhat ◽  
Ramakrishna Dileep ◽  
Sandya Rani

Transition metal complexes of 5-bromosalicylidene-4-amino-3- mercapto-1,2,4-triazine-5-one with metal precursors, such as Cu(II), Ni(II), Co(II) and Pd(II), were synthesized and characterized by physicochemical and spectroscopic techniques. All the complexes are of the ML type. Based on analytical, spectral data and magnetic moments, the Co(II) and Ni(II) complexes were assigned octahedral geometries, while the Cu (II) and Pd(II) complexes square planar. A study on the catalytic oxidation of benzyl alcohol, cyclohexanol, cinnamyl alcohol, 2-propanol and 2- methyl-1-propanol was performed with N-methylmorpholine-N-oxide (NMO) and molecular oxygen as co-oxidants. All the complexes and their parent organic moiety were screened for their biological activity on several pathogenic bacteria and were found to possess appreciable bactericidal properties.


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