Synthesis, characterization and bioactivity Study from azo – ligand derived frommethyl-2-amino benzoatewith some metal ions

: A Ligand (ECA) methyl 2-((1-cyano-2-ethoxy-2-oxoethyl)diazenyl)benzoate with metals of (Co 2+ , Ni 2+ , Cu 2+ ) were prepared and characterization using H-NMR, atomic absorption spectroscopy, ultra violet (UV) visible, magnetic moments measurements, bioactivity, and Molar conductivity measurements in soluble ethanol. Complexes have been prepared using a general formula which was suggested as [M (ECA) 2 ] Cl 2 , where M = (Cobalt(II), Nickel(II) and Copper(II), the geometry shape of the complexes is octahedral.


Introduction:
Azo compounds 1 are very important class of chemical compounds that is attracting study attention, they are highly colorful and have long been used as dyes and pigments. Transition metal azo compounds were instrumental in the development of coordination chemistry are widely used in industrial and biological systems. Azo compounds are very important molecules, these compounds derivatives and their metal complexes are very important pigments for synthetic leather and vinyl polymers. Coordination compounds (complexes) play a significant role in our life. Coordination compounds characteristics are the most important way in determining the chemistry of the transitional elements. Their study contributes in quietly understanding the chemistry of organometallic and inorganic compounds, and chemical bonds as a whole. The figure of possible coordination compound is almost infinite 2 . Inorganic compounds especially, transition metals, have played a significant part in the development of some cosmetic compounds and new metal-based drugs. Previously, complexes have been regarded as of interest only to the theoretical and to the inorganic chemists. However, these complexes are revealing a vital role in biochemistry, polymerization processes, and analytical chemistry through organic compounds preparation 3 .
Transition metals, in particular, have played a key role in the creation of new metal-based pharmaceuticals and cosmetic compositions. Copper, for example, is one of many transition metals used in cosmetics (Cu). Nickel a transition metal is utilized as a skin sensitizer in cosmetics. Nickel, on the other hand, is one of the most poisonous transition metals 4 .The aim of the work is preparation metal complexes from the Ligand (ECA) methyl 2-((1-cyano-2-ethoxy-2oxoethyl)diazenyl)benzoate, Characterization of ligands and prepared complexes by different techniques and study of bioactivity of these complexes .

Materials and Methods:
All the used chemical are supplied by either Fluka or Merck were of reagent grade and used as supplied. Ultra Shield 300 MHz (Bruker, Switzerland) was used to identify HNMR Spectra at University of Al-Bayt, Jordon. Shimadzu FT-IR infrared spectrophotometer was used to record absorption in the region of (4000-400cm-1 ) by using a KBr disc. Shimadzu UV-Vis. (160A) spectrophotometer was used to identify UV-Visspectra in ethanol solution. Shimadzu AA680G atomic absorption spectrophotometer was used to identify metal content atomic absorption technique of the complexes. A balanced magnetic susceptibility model (MSBKT) in the Faraday method was used to measure the magnetic moment (μeff B.M).Melting points were measured by the Stuartmelting point apparatus. Philips PW Digital conductivity meter was used to measure conductivity of the prepared compounds.
Preparation of the ligand (ECA) 5 Methyl-2-amino benzoate solution (1.3ml, 0.01mole) in HCl (3ml) was concentrated and cooled to (0-5°C), then sodium nitrite (1.5gin 10ml of water) cooled solution was added drop by drop over 10 minutes. At the same temperature, the reaction mixture was agitated for 30 minutes. Drop by drop, over 15 minutes, the mixture was added to an ice-cold combination of ethyl cyanoacetate (0.01mole) and sodium acetate (4.1g, 0.05mole) in ethanol (30ml). After that, the solution was stirred for 30 minutes and then allowed to sit at room temperature for (2 hours). The solid product was recrystallized after it was produced and collected from ethanol to give the orange crystals (ECA), m.p (142-144˚C), and yield (75%). The reaction is shown in scheme 1.

Preparation of complexes
A solution of metal chloride containing (0.11g, 0.11g and 0.076g) (1mmole) of CoCl2.6H2O, NiCl2.6H2O, and CuCl2.2H2O respectively was added to a solution of the ligand (ECA) (0.25g, 2mmole) in ethanol (5ml). After stirring for three hours, a colored precipitate was formed at room temperature. The rustling solids were filtered off from ethanol then dried at 50˚C in oven.

Result and discussion
The isolated compounds which are crystalline solids, were soluble ethanol, dimethyl formamide (DMF), and dimethyl sulphoxide (DMSO). The conductivity measurements in ethanol pointed out the electrolytic behavior. The molar ratio method was followed to measure the ratio of metal ion to ligand in complexes (M:L).
Ethanol was used as a solvent. The (M: L) ratio was (1:2). Table. 1 includes the physical properties; the magnetic measurements (μeff B.M) for the complexes.

Spectra studies
The 1 HNMR In DMSO, the spectrum of the ligand (ECA) was obtained, and Fig.1, shows the following signals: (DMSO) singlet (s) at (2.50) ppm, triplet (t) at (1.35) ppm for (3H, CH3), singlet (s) at (3.9) ppm for (3H, OCH3), quartet (q) at (4.34) ppm for (2H, OCH2), and multiplet (m) at (7.2-8.0) ppm for (4H, Ar-H). The IR spectra of the ligand (ECA) and its complexes are shown in Table  2. In the free ligand, the prominent absorption bands were at (1701, 1583) cm -1 and (2222)  is shown in Fig .2. The IR spectra of the cobalt complex is shown in Fig. 3. The bands were in a range between (1637-1508) cm -1 and deviated from lower frequencies by (64-193) cm- 1 . This shows that the oxygen atom at the (C=O) group in methyl ester 5 is coordinated. A band of (C=N) was missing, indicating that the nitrogen atom of (C=N) was not coordinated. (N=N) 6 caused a band in the ligand spectra at (1454) cm -1 . Complex spectra show that this band was around (1436-1373) cm -1 and that it deviated to lower frequencies by (81-18) cm -1 . This shows that the ligand (ECA) is coordinated through the azo nitrogen 7  The spectrum of the ligand Table. 3 shows the assignments and absorptions that were related to the ligand and its complexes Fig. 4, displays an electronic spectra of ligand (ECA) with absorption bands at 253 nm 39525 cm -1 and 361 nm 27710 cm -1 , which might be attributed to (π π *) and(n π*) transitions 9 .

[Cu(ECA)2] Cl2 complex
The absorption bands observed at    The ligand (ECA) combined with Co, Ni, or Cu complexes showed biological activity which was studied by using the inhibition method for four types 13 of pathogenic bacteria and Candida albicans fungi. Staphylococcus aureus and Bacillus subtilisare two forms of gram-positive bacteria. Escherichiacoli and Pseudomonas aeruginosa were the second and third gram-negative bacteria, respectively. To all species of bacteria, the chemicals show no inhibitory diameter. Under similar experimental settings, the results suggest that the complexes are more active than the ligand because of partial sharing of its positive charge with the donor groups and possible electron delocalization over the whole chelate ring such. The results for the compounds, the results as modified to the literature 13 are shown in table 4 and Figure 7.

Conclusions:
In this study new novel complexes are synthesized and recognized by a variety of spectral and physicochemical analyses. The findings show that the synthesized ligand behave as tridented coordinating with metal ions through three donor atoms (O in C = O, N in N=N and N in C=N), the complexes prepared have geometry octahedral, therefore the study of bioactivity for all compounds prepared show No significant Zone for all types bacteria Staphlococcus aureu, Psedomonas aeruginosa,Bacillus subtilis ,Escherichia coliand Candida albicans fungi.