Synthesis and characterization of new azo-linked Schiff bases and their cobalt(II), copper(II) and nickel(II) complexes

Abstract

Azo compounds were prepared by the reaction between benzenediazonium chloride and 4-amino-5-hydroxy-2,7-naphthalenedisulfonic acid monosodium salt under alkaline conditions. Two new azo-linked Schiff base ligands, 4-(3-methoxysalicylidene)-5-hydroxy-6-(2-hydroxyphenylazo)-2,7-naphthalene disulfonic acid disodium salt (H 2 L) and 4-(3-methoxysalicylidene)-5-hydroxy-6-(2-hydroxy-4-cholorophenylazo)-2,7-naphthalenedisulfonic acid disodium salt (H 2 L 1 ), have been synthesized. Also, the new Cu II , Ni II and Co II complexes of the azo-linked Schiff base ligands were prepared and characterized by infrared spectra, UV-Vis, 1 H-and 13 C-n.m.r., attached proton test (APT) and distortionless enhancement by polarization transfer (DEPT) and atomic absorption spectroscopy, mass spectrocopy, elemental analyses, thermogravimetric analysis, conductivity and magnetic measurements. It was determined that the synthesized ligands were comprised of six-membered rings due to intramolecular hydrogen bonding. The results suggested that condensation of the azo-derivative compounds and o-vanillin in a 1:1 molar ratio produces mononuclear Schiff base ligands with an ONO donor set. Preliminary histological studies were made. Magnetic moment studies showed that all complexes have a tetrahedral configuration.

Studies on Synthesis and Spectral Characterization of Some Transition Metal Complexes of Azo-Azomethine Derivative of Diaminomaleonitrile

“…is assigned to the stretching vibration of the diazo group of the ligand and the infrared spectra of the complexes did not show any frequency shi of the -N=N-band, which may be explained by nonparticipation in complex formation [27]. In addition to other bands, the vanadyl complex shows the characteristic V=O asymmetric stretching frequency at 940 cm −1 .…”

Fluorescence, Biological Activity and Spectroscopic Studies of Azo-linked Schiff Base Ligand Type (ONO) and Its Complexes with CrIII, CoII NiII and CdII Ions

“…The ligand spectrum reveals a band at (1489.1) cm -1 may refer to (N=N) azo group [21], this band, in the infrared spectra of the complexes, did not show any wave number shift and appeared at (1489. II ions respectively, which may be explained by non-participation of azo nitrogen atoms in complex formation [22].…”

2-{(E)-[(4-Anilinophenyl)imino]methyl}-4-[(E)-(4-methoxyphenyl)diazenyl]phenol

“…The well known applications of azo dyes in acid-base indicators and chemical sensors and as electron-transfer catalysts have attracted the interest of many investigators (Tunçel & Serin, 2006). The versatile applications of azo compounds in various fields include dyeing textile fibres, colouring different materials, plastics, biological medical studies, lasers, liquid crystalline displays, electro-optical devices and ink-jet printers in high-technology areas (Gregory, 1991).…”