Synthesis, characterization and electrochemical properties of copper(II) complexes with novel bidentate salicylaldimines derived from 3,5-di-t-butyl-2-hydroxybenzaldehyde

Abstract

Mononuclear copper(II) complexes of novel bidentate salicylaldimines (L x H) have been synthesized by the addition of Cu(Ac) 2 Á 2H 2 O to a mixture of 3,5-di-t-butyl-2-hydroxybenzaldehyde (3,5-DTB) and biologically active amines, 4-(3-aminopropyl)morpholine, 1-(3-aminopropyl)-2-pyrrolidinone and 1-(3-aminopropyl)-2-methylpiperidine. In this study N-[1-(3-aminopropyl)imidazole]-3,5-di-t-butylsalicylaldimine (L 1 H) was synthesized by reaction of 3,5-DTB and 1-(3-aminopropyl)imidazole followed by complexation with copper(II). The complexes were characterized by FTIR, UV-VIS, ESR, MS, 1 H and 13 C NMR spectroscopy, magnetic susceptibility measurements and thermogravimetric analysis (TGA) and also by electrochemistry. The room-temperature powder ESR spectra of these complexes are similar and exhibit axially symmetric g-tensor parameters with g k > g ? > g e suggesting that the copper(II) atom has a d x 2 Ày 2 ground state characteristic of square-planar or square-pyramidal stereochemistry. Thermal analysis indicated that Cu(L 3 ) 2 had the highest thermal stability of the complexes and Cu(L 2 ) 2 the lowest. Cyclic voltammetric experiments showed that all of the Cu(II) complexes underwent one-electron transfer, mainly diffusion controlled, as indicated by the dependence of the peak current on the square root of the scan rate.

Synthesis and Evaluation of Antidiabetic Properties of a Zinc Mixed Ligand Complex in High-Fat Diet - Low-Dose Streptozotocin-Induced Diabetic Rats

“…Moreover, the absence of the singlet in the region of δ 9.35 ppm due to the presence of phenolic proton and the presence of new one showed a characteristic new peak centered between δ 4.79 ppm, which confirms the presence of coordinated water molecules in the complex [31]. C NMR spectrum of zinc complex, the peaks around δ 115-154 ppm were due to the presence of aromatic carbons.…”

Co(II) and Cu(II) Schiff base complexes of bis(N-(4-diethylamino-2-methylphenyl)-3,5-di-tert-butylsalicylaldimine): Electrochemical and X-ray structural study

“…The Schiff base 1 was prepared by condensation of 3,5-di-t-butylsalicylaldehyde [26] with commercially available N,N-diethyl-2- 1,613 cm -1 in the spectra of copper(II) and cobalt(II) complexes, respectively, indicating coordination of the azomethine nitrogen atom to metal [31,32]. Narrow intense bands at ca.…”

Imidazolium salicylaldimine frameworks for the preparation of tridentate N-heterocyclic carbene ligands

“…The Schiff base 1 was prepared by condensation of 3,5-di-t-butylsalicylaldehyde [9] with commercially available N- (3-aminopropyl)imidazole by the method reported [10]. Subsequently, N-salicylaldimine armed imidazolium salts 2 were prepared in good yields by quarternization of the imidazole moiety of the salicylaldimine using benzyl halides (benzyl a, 2,4,6-trimethylbenzyl b, 2,3,4,5,6-pentamethylbenzyl c) as the reactant in toluene at reflux in high yields (ca.…”

“…IR spectra were recorded on a Perkin-Elmer Spectrum RXI FT-IR spectrometer as KBr pellets. The starting Schiff base was prepared by known method [10].…”