Mn(II),Fe(III),Co(II)and Rh(III) complexes with azo ligand: Synthesis, characterization, thermal analysis and bioactivity

New series of metal ions complexes have been prepared from the new ligand [4-Amino-N-(5-methyl-isaxazol-3-yl)-benzenesulfonamide] derived from Sulfamethoxazole and 3-aminophenol. Accordingly, mono-nuclear Mn(II), Fe(III), Co (II), and Rh(III) complexes were prepared by the reaction of previous ligand with MnCl 2 .4H 2 O, CoCl 2 .6H 2 O, FeCl 3 .6H 2 O and RhCl 3 H 2 O, respectively. The compounds have been characterized by Fourier-transform infrared (FTIR), ultraviolet–visible (UV–vis), mass, 1 H, and 13 C-nuclear magnetic resonance (NMR) spectra and thermo gravimetric analysis (TGA& DSC) curve, Bohr magnetic (B.M.), elemental microanalyses, metal ions, chloride containing, and molar conductance.These reviews uncovered octahedral geometries for complexes. The investigation of complexes development by means at molar proportion andoccupation strategy in DMF solution has been researched, and results were reliable to those found in the solid complexes with a proportion of (M:L) as (1:2).


Introduction
The coordination compounds resulting from azo compounds are of increasing importance in the various fields of industry, agriculture, medicine and medicine, and as auxiliary factors, and what helped them in this is the effective groups present in the compound originally, which gave them additional stability and effectiveness at the same time [1][2][3][4] . Antibiotics are substances which, even at low concentrations, inhibit the growth and reproduction of bacteria. Infectious disease treatment would have been inconceivable today without antibiotics 5 . In this work, we have tried in using diazotization coupling reaction between sulfamethaxazole (sulfur-containing organic compound) and 3aminophenol(m-aminophenol)forming (E)-3-((4amino-2-hydroxyphenyl)diazenyl)-N-(4methylisoxazol-3-yl)benzenesulfonamide can be classified as azo compound that in turn coordinate with each of Mn(II), Fe(III),Co(II)and Rh(III) metal ions in 2:1 ratio. In such reactions, the use of acidic media to prepare the intermediate compound is the basis for the preparation of important azo compounds with widespread uses in various fields 6-RhCl 3 H 2 O Equipped with (Sigma-Aldrich, Merck, and others). The complexes' molar conductances were measured by using a Conductometer WTW at 25°C at a concentration of 1×10 −3 M.DMSO was used to dissolve all of the complexes (DMSO). On a mass spectrometry (MS) QP50A: DI Analysis ShimadzuQP-2010-Plus (E170Ev) spectrometer, the UV-Vis spectrophotometer UV-1800 Shimadzu was used to analyze the spectra in the ultravioletvisible (UV-Vis) range, the IR Prestige-21 was used to investigate the (FTIR) spectra, and the Perkin-Elmer Pyris Diamond TGA&DSC was used to conduct thermogravimetric studies. A Brucker500 MHz was used to record the proton nuclear magnetic resonance ( 1 H& 13 C-NMR) spectra for ligand in DMSO-d 6 . The Euro vector model EA/3000, single-V.3.O-single, was used to conduct elemental analyses (C, H, N, S and O). Metal ions were estimated as metal oxides using a gravimetric method, mass spectra for substances were recorded..

Synthesis of azo dye ligand
The ligand in Scheme 1, was synthesized according to the suggested method 10

General method for the preparation of metallic ions complexes
The metallic ions complexes were made with metal chlorides for Mn(II), Fe(III), Co(II) and Rh(III). An amount of (0.373g, 1m.mol) from azo ligand, dissolved in 10 mL absolute ethanol, was gradually added in drops wise with stirring to a (0.5m.mol) amount of [1:2] M:L for Mn(II), Fe(III), Co(II) and Rh(III), MnCl 2 .4H 2 O, CoCl 2 .6H 2 O, FeCl 3 .6H 2 O and RhCl 3 H 2 O. The mixture was heated for 2 hours at (50-70)°C, then chilled in an ice bath until precipitated, then left overnight. To remove any unreacted components, the solid complexes were separated and washed with distilled water and a little amount of hot ethanol. Finally, vacuum desiccators were used to dry the complexes. The analytical and physical properties of the ligand and its metal complexes are summarized in Table 1.

Result and discussion
Physical and chemical properties of azo dye ligand Microscopic analysis of the elements, the infrared spectrum, the proton NMR spectrum, carbon NMR spectrum, the malar conductivity, TGA & DSC and Mass, and the azo complexes was used to identify the prepared ligands and their complexes. Table 1 shows this with some physical properties

Electronic spectra measurements
The UV-Vis spectra of the ligand LH and its complexes. With absorption maxima at (253 nm, 38759.6 cm -1 ) ascribed to the π⟶π* transition and two peaks at (435 nm, 22988.5 cm -1 ) attributed to the n⟶π* transition a peak with a high intensity band formed with absorption maxima. There were six absorption peaks in the electronic spectra of the [Mn(L) 2 (H 2 O) 2 ] complex. The peaks at 275nm and 360nm is ascribed to the ligand, while the (π⟶π*) complex, the peak at 402 nm is ascribed to the ligand, while the n⟶π* complex and three peaks in the (602nm) (713nm) and (809nm) while the one peak at are attributed to the (d-d) electronic transitions types 6 A 1g ⟶ 4 A 1g , 4 E g (G), 6 A 6g ⟶ 4 T 2g (G)and 6 A 6g ⟶ 4 T 1g (G)respectively, Furthermore, the magnetic moment of the Mn(II) (d 5 ) complexes is found to be (3.71 B.M) [14][15][16] . All the above mentioned data correspond to an octahedral geometry. The electronic spectrum of the paramagnetic (3.66B.M)Fe(III) complex was ascribed to the peak at 280nm and 360nm is ascribed to the ligand, while the(π⟶π*) and ( n⟶π*), and the three peaks at 684nm, 850nm and 996nm was assigned to the 6 A 1g ⟶ 4 A 1g , 4 E g (G), 6 A 6g ⟶ 4 T 2g (G)and 6 Table 2 show the data of complexes electronic spectra and molar conductivity.

Liquid chromatography-mass spectrometry (LC-Mass) measurements
The electron impact of fragmentation was used to acquire mass spectra of the ligand and metal complexes. High-resolution MS of the free azo ligand and its complexes, as well as large fragments linked to breakdown products, was obtained in general. The electron impact mass spectrum of ligand LH. This ligand molecular weight is calculated to be 373.39g/mol. The spectra showed a peak at 373 m/z, which was attributed to [M] + and corresponded to a novel azo moiety C 16 H 15 N 5 O 4 S.Their brightness indicates the pieces' stability Fig.4 depicts the mass spectrum of the Mn(II) complex. The complexmoiety C 32 H 32 S 2 N 10 MnO 10 had a peak at 836 m/z, which corresponded to the complexmoiety C 32 H 32 S 2 N 10 MnO 10 in the spectrum. Fig.5 depicts the mass spectrum of the Fe(III) complex. The compound moiety C 32 H 30 N 10 O 9 FeClS 2 was identified by a peak at 854 m/z in the spectra. The electron impact mass spectrum of the Co(II) complex. The complexmoietyC 32 H 32 N 10 O 10 CoS 2 was identified by a peak at 839 m/z in the spectra. The electron impact mass spectrum of Rh(III). This complex molecular weight is calculated to be 901.13/mol. The spectra showed a peak at 901 m/z, which was attributed to [M] + and corresponded to a novel azo moiety C 32 H 30 N 10 O 9 S 2 RhCl. [21][22][23] . In Schemes 2-6, suggested fragmentation routes and structural assignments of pieces are given.

Infrared spectra measurements
The azo ligand spectra and their metal chelates complexes with Mn(II), Fe(III), Co(II) and Rh(III) have been compiled, and the data has been organized in Table.3. The ligand displayed bands at 3377, 3318and 1618 cm -1 that were ascribed to the stretching vibration asυ(NH 2 ), sυ(NH 2 ), and out of plane of δ(NH 2 ), but these bands were reduced to a non lower frequency in the spectra of all generated compounds, indicating not coordination with a metal ion [24]. The (N=N) stretching vibration was attributed to the band seen at 1467, 1406 cm -1 24-26 in the unbound azo ligand (LH). This band was discovered in the compounds' spectra around (1464-1442),(1444-1411)cm -1 .The engagement of the azo group in chelation was verified by a change in the azo group of the azo ligand [25][26][27] .In addition, prior study has shown that in the presence of transition metals, the azo-dye nitrogen is always more likely to favor complication 26 . Because of the presence of coordinated water molecules in the complexes, it was difficult to confirm that this group was involved in chelate formation. The existence of coordinated water molecules in the coordination sphere was ascribed to the appearance of OH bands in the IR spectra of the Ni(II) complex in the (3733-3655)cm -1 . In addition, stretching vibrations in the range of (1544-1579)and (737-768) cm -1 were shown to correlate to ν(M-OH 2 ) in (500-569)cm -1 This is a strong evidence that water molecules are involved in the coordination process 27 . For the unbound ligand, the IR spectra revealed a wide stretching vibration band at 3492 cm −1 , which might correlate to the OH of the phenolic group 25 . The band at 1284 cm −1 was assigned to the ν(C-O) stretching vibration of the phenolic group of the free azo-dye ligand due to the coordination with the metal ions 27 , and the band at 1284 cm −1 was attributed to the ν(C-O) stretching vibration of the phenolic group of the free azo-dye ligand. After this, the IR spectra of all produced compounds revealed that the azo-dye ligand connected to metal ions through two sites: the azo group's nitrogen site, and oxygen site via deprotonation of the phenolic

Study of Thermo Gravimetric Analysis for compounds by TGA & DSC Curve
The results of DSC and TGA of ligand and Fe and Co complexes are given in Table 4 and Fig.6

Vital diagnosis
The findings showed that the produced ligand and its constituents were biologically efficient, since the experiment was carried out in aerobic circumstances at a temperature of 37°C. Drilling was used to exposing every pathogenic active compound pathogenic bacteria to two different types of pathogenic bacteria S aureus, P aeruginosaand FungiPexpansum, F graminearum, M phasealina, and C albicans which were used the DMF solvent with 1×10 -3 M concentrations and showed different efficacy to the negative and positive stain-bacteria of the compounds. The data are shown in the table 5 below in (mm) 35-38 .

Study complexes in gas stat (theoretical studies)
The Theoretical study for the formed entity (LH) was accomplished at its gaseous state in order to detect the stretching vibrations and Fourier transform spectra and make a competition for them with the practical returns and detect the mistake percentage, and so forth for the complexes, show as electrostatic potential (HOMO and LUMO) as 2D& 3D Fig.9.

Co-Complex
Rh-Complex Figure 10. Conformational structure of (LH) and their metal complexes

Conclusion
The ligand chemical is a brand-new azo dye that has never been made before. 1 H & 13 C-NMR, IR, UV-Vis, TGA, DSC and Mass spectrum techniques were used to identify the ligand and its complexes. The estimated values and the results of the elemental micro analysis were found to be in good agreement. The ligand bidentate character was suggested by IR measurements. Complexation happens through -NO moiety, according to multinuclear NMR data. Complex molecules are more stable, therefore the process requires less equipment to advance. The biological activity of some prepared compounds against two types of bacteria and four type's fungi was also studied, and it gave varying inhibition values.

Authors Contribution:
Al-Hamdani AAS presented the idea, analysis, discussion of the results and writing of the manuscript. Shaimaa Mohammed Reda contributed to the design and implementation of the esearch, laboratory work, verified the analytical methods and discussed the results and contributed to the final manuscript