A New Method of Synthesis of Azo Schiff Base Ligands with Azo and Azomethine Donors: Synthesis of N‐4‐Methoxy‐benzylidene‐2‐(3‐hydroxyphenylazo)‐5‐hydroxy‐aniline and Its Nickel(II) Complex

Abstract

A new method for the synthesis of azo Schiff an base ligand in which the azo and azomethine groups are coordination sites was developed through a Schiff base precursor. The precursor, N-4-methoxybenzylidene-3-hydroxyphenylamine (SB) derived from 3-aminophenol was regioselectively coupled with a diazonium ion para to the hydroxyl group of the amine component of the Schiff base. The para selectivity was controlled by the directing effect of the hydroxyl group. The ligand and its nickel(II) complex were characterized by elemental analyses, IR and UV-Vis spectroscopy. The analytical and spectral data supported the mononuclear formulation of the complex with metal to ligand ratio (M∶L＝1∶2) and suggested a square planar geometry for the complex.

Antibacterial evaluation of Some Synthesis Complexes of Azo-dye Ligands.

“…While IR spectra of the ligand (AZD2) exhibit band at (3219) cm -1 , which was assigned to the stretching vibration of (OH) phenol group (15) , while for all complexes are appear in range (3197-3205) cm -1 were shifted to lower frequency with change in shape in spectra of complexes, which is an indication of the engagement of this group in the coordination with the metal ion. The band in range (1587-1589) cm -1 for metal complexes are due to ν(C=N) stretching frequency of azomethin group, but for free ligand it appear at (1595 ) cm-1 shifted to lower frequency, which…”

“…This is indicative of the coordination of the imine nitrogen to the metal. In the free ligands, the sharp bands observed in the range (3284) cm -1 is due to ν (OH) stretching frequency of carboxylic group (15) . In all complexes were moved to lower frequencies.…”

“…The spectra of the complexes of Mn(II) shows an intense bands in range (23800 -47615) cm −1 of tetrahedral geometry may be assigned to charge transfer transitions (13,15) . The data of magnetic susceptibility confirm with the 5 unpaired electrons in d 5 system for metal complexes.…”

Synthesis, spectral characterization, thermal analysis and electrochemistry properties of Ni(II) complexes derived from azo dyes

“…However, during the recent years, considerable attention has been paid to the thermal behavior of transition-metal Schiff base complexes containing Schiff base-substituted salicylaldehyde derivatives, which is one of the important properties of complexes indicating thermal stability and decomposition process under various conditions [9][10][11][12][13]. Regarding the industrial importance of metallized azo dyes relative to their structures, they can be classified into two main types: those in which the azo group participates in the coordination to the metal ion with formation of the chelate ring and those in which it is not [14]. In the most cases, metallochelates with five-, six-or five-, and six-membered coordination modes were obtained from the azo-ligating compounds.…”

Synthesis, Spectroscopy, Thermal Analysis, Magnetic Properties and Biological Activity Studies of Cu(II) and Co(II) Complexes with Schiff Base Dye Ligands

“…The azo group possesses excellent donor properties and is important in coordination chemistry [1,2,3], and some azo compounds have been shown to possess good antibacterial activity [4,5]. Schiff bases are well known to have antifungal, antitumor and herbicidal activities [6,7,8,9,10,11].…”