IHJPAS. 36 (3) 2023 214 This work is licensed under a Creative Commons Attribution 4.0 International License *Corresponding author: azraa.ghazi1105a@csw.uobaghdad.edu.iq Abstract Azo-ligand-(HL) ([4- ((2-hydroxyquinolin-3-yl) diazenyl) -N- (5-methylisoxazol-3yl) benzenesulfonamide]), (2- hydroxy quinolin derivative),reacts with the next metal ions (Cr (III), Fe (III),Co (II) and Cu(II)) forming stable complexes with unique geometries such as(tetrahedral for bothCo (II) and Cu (II), octahedral for both Cr (III) and Fe (III)). The creation of such complexes was detected by employing spectroscopic means involving ultraviolet-visible which proved the obtained geometries, Fourier transfer proved the involvement of coordinated water molecule in all complexes besides the pyrolysis (TGA & DSC) studies proved the coordination of water residues with metal ions inside the coordination sphere as well as chlorine atoms. Moreover element-micro-analysis and AAS that gave corresponding outcome with theoretically counting outcome. Magnetic quantification scan also indicates the unique geometries of complexes. The degradation of reactive oxygen entities for the compounds were estimated toward (DPPH-radical then matched to the standard-natural antioxidant, Gallic acid. The incomes display good radical degradations-activities.The lower IC50 value, the higher antioxidant activity. Depending on this conception, the order of our compounds besides Azo-species-HL is as follows: (G_A<[Co(L)(H2O)Cl]> [Cr(L)(H2O)Cl]> [Fe(L)(H2O)2Cl2]> [Cu(L)(H2O)Cl]). Keywords: antioxidant, azo dye, Mass spectroscopy,quinolin derivative, Thermal analysis. 1. Introduction Azo group N=N contributes in the brilliant color of its compounds in vis-area in addition to its sensitivity toward pH changes which can be strong reason of their usage as colorant for tissues and indications in analytical chemistry. Azo compounds [1-4] display geometrical isomaresim when exposed to light, trans- isomers are stable and converts into cis-isomer when exposed to light. Such doi.org/10.30526/36.3.3068 Article history: Received 11 October 2022, Accepted 3 November 2022, Published in July 2023. Ibn Al-Haitham Journal for Pure and Applied Sciences Journal homepage: jih.uobaghdad.edu.iq Cr (III), Fe (III), Co (II) and Cu(II)Metal ions Complexes with Azo Compound Derived from 2-hydroxy Quinoline Synthesis, Characterization, Thermal Study and Antioxidant Activity Adhraa Ghazi Abdulrazzaq* Department of Biotechnology of medical- instrument-technical, AL-Israa-University- College, Baghdad, Iraq. azraa.ghazi1105a@csw.uobaghdad.edu.iq Abbas Ali Salih Al-Hamdani Department of Chemistry, College of Science for Women, University of Baghdad, Iraq. abbasas_chem@csw.uobaghdad.edu.iq https://creativecommons.org/licenses/by/4.0/ mailto:azraa.ghazi1105a@csw.uobaghdad.edu.iq mailto:azraa.ghazi1105a@csw.uobaghdad.edu.iq mailto:azraa.ghazi1105a@csw.uobaghdad.edu.iq mailto:abbasas_chem@csw.uobaghdad.edu.iq mailto:abbasas_chem@csw.uobaghdad.edu.iq mailto:abbasas_chem@csw.uobaghdad.edu.iq IHJPAS. 36 (3) 2023 215 operation called photochromic when completely conversion occurs [5].When this operation accompanied with high differentiation in dipole moment, making these substances of high storage optical data.[6] Azo complexes such as azo-quinolin, display nonlinear optical features, such features occupy important role in optical data storage and telecommunication's [7-9].Azo species had numerous interests as indicators to extract and identify tiny amounts of metal ions in various samples.[10-12] Azo-complexes have studied intensively because of their important features and applications such as catalysts, antimicrobial, erosion inhibitors and anticancer.[13-15] Azo- complexes that derived from Sulfamethoxazole and pyrazole [16, 17] display unique activities against tuberculosis. Azo compounds such as ruthenium complex, which derived from quinolin, shows anticancer activity because of their role in photodynamic therapy at long wavelengths.[18, 19] Azo-complexes are also used as photo sensors in double -photon photodynamic therapy to cure cancer because of their lower toxicity in dark and high tendency to produce active O-species in addition to their ability to absorb di-photon [20, 21]. The acidic features of π-orbits of N- heterocycls that involved in azo entities provide additional stability for various oxidation states of metal ions. Large amounts of azo-dyes are added to food products to enhance the appearance and feed features [22, 23] .Azo complexes especially Cr (III) complex with acidic dyes shows many usages in toners and dying for skin and hair [24].According to their large industrial applications such as medicinal and spectroscopic-analysis, we aimed to prepare new series of azo-complexes. By the reaction between azo-compound and each of the next metal ions: (Cr (III), Fe (III), Co (II) and Cu (II)) then using many techniques to identify the formation of such complexes. 2. Chemicals and method 2.1 Materials and instrumentation Materials have supplied from the trading suppliers, (Sigma Aldrich, Merck, and others). The eurovector model EA/3000, singleV3O, has employed to achieve (C-H-N-Sand0). Mineral-ions have determined as M-O employing a gravimetric-approaches. molar-conductivity has estimated employing Conduct meter W-T-W, 25-°C. 1×10-3 M. D/M/S/0 has employed as solvent. Mass- spectra for substances have collected using mas.s spectrometry (MS) Q-P-50-A-D-I Analyses Shimadzu QP(E170Ev) -2010-Pluss spectrometer. The spectra were analyzed using a Shimadzu UV-1800 UV-visible spectrophotometer. The FT_IR Prestige-21 was used to investigate the Fourier transform infrared (FTIR in burker) spectra (ranges between 4000-600 cm-1, shimadzu ). 2.2 General approach of azo-ligand (HL) and metal complexes synthesis 2.2.1Synthesis of azo-ligand (L) 4-((2-hydroxyquinolin-7-yl) diazenyl) -N-(4-methylisoxazol- 3- yl) benzene sulfonamide Azo-ligand was synthesized according to diazotization-coupling approach at which, (2.05 g, 0.005 mol) from Sulfamethoxazole were dissolved in a mixture consisting of 4 mL of 37% HCl and 35 mL distilled water DW. Then this mixture allowed to be cooled in a temperature starts at 0⁰C up to 5⁰C followed by discontinuously addition of (0.375 g, 0.005) mol NaNO2 solution which in turn dissolved in 30 mL DW, with continuous stirring and under controlling the range of temperature, which must be kept around 5⁰C for 30 minutes. After 15 minutes, diazotization-coupling operation occurs resulting in diazonium salt, which in turn added through filtered funnel containing cube of ice of DW onto 0.726 g, 0.005 mol solution of 2-hydroxy quinoline dissolved in 50ml of absolute EtOH and 15 ml of 10% NaOH solution with cooling and continuous stirring. We can clearly observe the creation of reddish-brown precipitate Scheme 1, this precipitate is left for one hour IHJPAS. 36 (3) 2023 216 under 5 ⁰C, then filtered and washed several periods with distilled water. Finally, recrystallization process by absolute ethanol is carried out, followed by drying in oven at 50 ⁰C. yielding in 68% product having (130-133) ⁰C m. p. 2.2.2 Synthesis of metal complexes A specific amount of azoquinolin derivative, which dissolved in abs. EtOH, is added discontinuously with continuous stirring onto a specific amount for each of the next metal ion salts: (Cr (III), Fe (III), Co (II) andCu (II)) solutions. The resultant mixture is heated and refluxed for one hour up to 80 ⁰C, followed by cooling at room temperature, after 24 hours, a completely precipitation occurs, Figure 1.Then, solution containing- precipitate is filtered, washed several periods with distilled water and washed with little amount of cold ethanol. Finally, recrystallization process using absolute ethanol is carried out for the synthesized complexes. The molar ratio of the synthesized complexes was found to be 1:1 M: L. Figure 1. Azo-ligand (HL) and metal complexes synthesis. 3. Result and discussion 3.1 Magnetic nuclear resonance spectrum of ligand (1H-NMR &13C-NMR) Magnetic nuclear resonance spectrum of the new azo ligand was studied using dimethyl sulfoxide DMSO-d6 as solvent and TMS as standard reference. Figure 2 demonstrate the chemical shifts of these spectra. 1H-NMR spectrum of the ligand demonstrates the several chemical shifts but the most distinguishable feature is the absent of NH2 chemical shift compared to starting materials as denoted in Table 2. 13C-NMR spectrum demonstrates the next signals : (100.622 MHz, DMSO- d6): d 48.06 (C1), 167.70 (C13), 144.31 (C7), 121.95 (C18), 148.76 (C19), 125.18 (C15), 130.31 (C17), 134.31 (C9), 141.97 (C8), 115.39 (C16), 167.70 (C13), 151.10 (C11), 153.24 (C5), 195.60 (C12), 131.97 (C14), 162.15 (C4), 157.17 (C10), 179.82 (C2).[25,26]. IHJPAS. 36 (3) 2023 217 Table 1.1H-NMR data of ligand (HL) (ppm) δ Functional group Compound (1.08, 1H, singlet) Ar-OH C19H15N5O4S HL (10.51, 1H, singlet) N-H (7.68-7.95, 8H, multiplet) Ar-H (6.72-6.79, 2H, singlet) C-H (aromatic) besides CH3 C-H (3- quinoline) besides OH (2.60, 3H, singlet) CH3 (2.41-2.51) DMSO (solvent) Figure2.1H-NMR and 13C-NMR spectra of ligand (HL). 3.2 Physical and chemical properties Reactions of metal salts with ligand gave the synthetic complexes Scheme 1. The results of elemental analysis demonstrate 1:1 M: L stoichiometry for all complexes the elemental analysis results were compatible with theoretical calculated results as denoted in Table 2. Table 2.Some physical properties element microanalysis studies of compounds. Compound M_wt m-p_°C Color Eleme. Micro-ana. percentage estimate (calc.) C H. N. O. S M. Cl. C19H15N5O4S 409.42 130-133 Pale brown 55.50 (54.41) 3.62 (3.18) 17.10 (18.70) 15.55 (15.26) 7.39 (8.40) -- -- C19H18Cl2CrN5O6S 567.34 225 d Pale brown 41.60 (40.22) 2.65 (3.20) 13.84 (12.34) 15.98 (16.92) 6.43 (5.65) 8.88 (9.16) 13.15 (12.50) C19H18Cl2FeN5O6S 571.13 190 d Reddish Brown 40.14 (39.95) 4.01 (3.18) 13.31 (12.26) 15.98 (16.81) 10.01 (9.78) 10.01 (9.78) 13.03 (12.41) C19H16ClCoN5O5S 520.81 228-230 Pale brown 42.86 (43.82) 3.33 (3.10) 14.87 (13.45) 16.06 (15.36) 5.89 (6.16) 12.02 (11.32) 7.09 (6.81) C19H16ClCuN5O5S 525.43 200-201 Greenish brown 42.24 (43.43) 2.71 (3.07) 14.41 (13.33) 16.06 (15.23) 5.81 (6.10) 12.88 (12.09) 7.07 (6.75) D= decompose IHJPAS. 36 (3) 2023 218 3.3 UV-Vis studies of Azo-ligand (HL)and its complexes: Figure3 displays the electronic transitions of azo-ligand (HL), those transitions as follows: (π →π*) and n→π*+ (C.T) (L-L). Such transitions can apparently observe at (296 nm, 33783 cm-1) and (328 nm, 30487 cm-1) respectively. The presence of aromatic rings and unsaturated bonds results in (π →π*) transition and the presence of hetero atoms especially unshared electrons causes in n→π*+ (C.T) (L-L). Figure4 and Table 3 illustrate the electronic transitions of [Cr(L)(H2O)2Cl2] complex at ultra violet region in the range (298 nm, 33557 cm -1) and (377 nm, 26525 cm-1) those absorption bands belong to (π →π*) and (n→π*) electronic transitions respectively. The presence of non-bonding electrons or heteroatoms causes (n→π*) transition, while the presence of unsaturated bonds and aromatic rings causes (π →π*) transition.[27] Moreover, the transitions that happened in metal (d-d), can strongly prove the coordination. Those are as follows;4A2g→ 4T2g (F) , 4A2g→ 4T1g (F) and 4A2g→ 4T1g (P), which observed at (615 nm, 16260 cm-1), (679 nm, 14727 cm-1 ) and (749 nm, 13351 cm-1) respectively. Those transitions and magnetic moment (3.89 B.M) can definitely supports octahedral geometry. We can apparently observe the occurrence of coordination in [Fe(L)(H2O)2Cl2] complex, because of the observed shifting in absorption range of detected transitions at ultra violet region compared to the range of the same transitions in free azo residue to be appeared at (331 nm, 30211 cm-1) and (573 nm , 17452 cm-1). The mentioned wave numbers belong to (π →π*) and (π →π*) + C.T transitions respectively. In addition to single d-d transition in the metal itself that denoted as 6A1→ 4T1(G) at (783 nm, 12771 cm-1) and the magnetic moment (5.62 B.M) can definitely supports Octahedral geometry.[28,29] [Co(L)(H2O)Cl] complex shows electronic transitions in ultra violet region, those are (π→π*), (n→π*) and (n→π*)+(C.T) at (309 nm, 32362 cm-1) (340 nm ,29411 cm-1) and (394 nm, 25380 cm-1) respectively. Additionally, 4A2→ 4T2 (F), 4A2→ 4T1 (F) and 4A2→ 4T1 (P)(d-d transitions) can clearly observe at (690 nm, 14492 cm-1),(789 nm, 12674 cm-1) and (825 nm, 12121 cm-1) respectively. Those transitions and the magnetic moment [3.93 B.M] can definitely supports tetrahedral geometry.[30][Cu(L)(H2O)Cl] complex shows the following transitions : π→ π* at (279 nm, 35842 cm-1), n→ π* at (319 nm, 31347 cm-1) and (n→π*)+ (C.T ) transition at (386 nm, 25906 cm-1) those are belong to azo residue . In addition to (d-d) transition that referred to as 2T2→ 2E at (834 nm, 11990 cm-1); the mentioned transition can definitely support Tetrahedral geometry of the complex.[31] All the electronic transitions information for the products have displayed in Table 2. Figure 3.UV-Vis spectrum of Azo-ligand (HL). IHJPAS. 36 (3) 2023 219 Figure 4. UV-Vis spectrum of Cr-complex. Table 3.UV-Vis spectral data of compounds. Compound λmax (nm) υ cm-1 ABS. ε max L mol- 1cm-1 Assignment ʌm cm2 Ω- 1mol-1 µeff B.M Azo-ligand (HL) 296 328 33783 30487 1.501 0.926 -- 332 π→π* n→π*+C.T(L→L) -- -- C19H18Cl2CrN5O6S O.h 298 377 615 679 749 33557 26525 16260 14727 13351 0.332 0.478 0.138 0.216 0.109 332 478 138 216 109 π→π* n→π*)C.T( 4A2g→ 4T2g (F) 4A2g→ 4T1g (F) 4A2g→ 4T1g (P) 18 3.89 C19H18Cl2FeN5O6S O.h 331 573 783 30211 17452 12771 0.838 0.194 0.246 838 194 246 π→π* n→π*(C.T) 6A1→ 4T1(G) 9 5.62 C19H16ClCoN5O5S T.d 309 340 394 690 789 825 32362 29411 25380 14492 12674 12121 0.416 0.380 0.510 0.106 0.046 0.047 416 380 510 106 46 47 π→π* n→π* n→π*+ (C.T ) 4A2→ 4T2 (F) 4A2→ 4T1 (F) 4A2→ 4T1 (P) 21 3.93 C19H16ClCuN5O5S T.d 279 319 386 834 35842 31347 25906 11990 0.501 3.001 1.854 0.436 501 3001 1854 436 π→π* n→π* n→π*+ (C.T ) 2T2→ 2E 12 1.76 3.4 LC-Mass spectra of the products: In Figure 5, we can apparently notice the peak that corresponds the molecular weight of ligand (HL) for the pieceC10H9N2O3S + and its abundance about 45%. In addition to other abundances for the rest of pieces including C9H6N3O +, C6H6NO2S + , C7H7 + , C2H6N3O +and C4H4NO + that corresponded the next abundances: 43% , 15% , 13% , 33% and 42% respectively. Mass information of [Fe(L)(H2O)2Cl2] in Figure 6 and Scheme 3, the molecular ion peak (M +) can detected at 535 m/z with relative abundance 59% besides the next patterns C10H10N3O3S + C9H5FeN2O +, C6H6NO2S +, C3H4FeNO +, C4H5N2O + and C6H6N +. Which corresponding to (252 m/z, 30%), (212 m/z, 57%) , (156 m/z, 58%), (125 m/z, 50%), (97 m/z, 70%) and (92 m/z, 45%) respectively.[32] Additionally, [Co(L)(H2O)Cl] complex in Scheme 4, illustrates the next IHJPAS. 36 (3) 2023 220 fragments: (M+) at 467 m/z with relative abundance 48%, C10H10N3O3S +, C9H5CoN2O +, C6H6NO2S +, C3H4CoNO +, C4H5N2O + and C6H6N + that corresponded to (252 m/z, 60%), (216 m/z, 52%), (156 m/z, 47%), (129 m/z, 35%), (97 m/z, 85%) and (92 m/z, 45%) respectively.[33] [Cu(L)(H2O)Cl] complex in Scheme 5 illustrate the next fragments: (M +) C19H14N5CuO4S + at (471 m/z, 41%), C10H10N3O3S + at (252 m/z, 48%), C9H5N2CuO + at (220 m/z, 40%), C6H6NO2S + at (156 m/z, 75%), C3H4NCuO + at (133 m/z, 7%), C4H5N2O + at (97 m/z, 58%)and C6H6N + at (92 m/z, 17%).[33] For [Cr(L)(H2O)2Cl2] in Scheme 6 has displayed in detail in Table 4. Scheme 2. Fragmentation analogues of Azo-ligand (HL). Scheme 3. Fragmentation analogues of Fe-complex. IHJPAS. 36 (3) 2023 221 Scheme 4. Fragmentation analogues of Co-complex. Scheme 5.Fragmentation analogues of Cu-complex. Scheme 6.Fragmentation analogues of Cr-complex. IHJPAS. 36 (3) 2023 222 Figure 5. LC-Mass spectrum of Azo-ligand (HL). Figure 6. LC-Mass spectrum of Fe-complex. Table 4. LC-Mass spectral data of compounds. Fragment Co-complex Extract mass Relative abundance Fragment Fe-complex Extract mass Relative abundance C19H16ClCoN5O5S C19H14CoN5O4S + C10H10N3O3S + C9H5CoN2O + C6H6NO2S + C3H4CoNO + C4H5N2O + C6H6N + 520 467 252 216 156 129 97 92 17% 48% 60% 52% 47% 35% 85% 45% C19H18Cl2FeN5O6S C19H13Cl2FeN5O4S + C10H10N3O3S + C9H5FeN2O + C6H6NO2S + C3H4FeNO + C4H5N2O + C6H6N + 571 535 252 212 156 125 97 92 12% 59% 30% 57% 58% 50% 70% 45% Fragment Cr-complex Extract mass Relative abundance Fragment Cu-complex Extract mass Relative abundance C19H18Cl2CrN5O6S C19H14Cl2CrN5O4S + C10H10N3O3S + 567 531 252 17% 25% 48% C19H16ClN5CuO5S C19H14N5CuO4S + C10H10N3O3S + 525 471 252 29% 41% 48% IHJPAS. 36 (3) 2023 223 C9H5CrN2O + C6H6NO2 + C4H5N2O + -- -- 209 156 97 -- -- 12% 45% 78% -- -- C9H5N2CuO + C6H6NO2S + C3H4NCuO + C4H5N2O + C6H6N + 220 156 133 97 92 40% 75% 7% 58% 17% 3.5 FT-IR studies: The absorption bands that observed in azo-species, Figure 7 are: stretching vibrational modes for each of the next functional groups: (NH) amine, (C-H) aromatic, (C-H) aliphatic, (N=N) azo band and (SO2) at (3381, 3091, 2977, (1448-1403) and (1160-1086)) cm -1 respectively. In FT-IR spectrum for [Cr(L)(H2O)2Cl2] complex in Figure 8, we can clearly notice the absorption band of coordinated water molecule in the range (3652 and 1600) cm-1that proves the involvement of such group inside the coordination sphere of the complex. Other absorption bands that detected were belonging to the stretching absorption bands for the next groups : N-H amino group at (3388 cm- 1), C-H aromatic at 3084 cm-1 , C-H aliphatic at 2977 cm-1, N=N at (1466 and 1387) cm-1 and SO2 group at (1145 and 1091) cm-1.[33] For [Fe(L)(H2O)2Cl2] complexwe can also observe the absorption band of coordinated water molecule at (3583 and 1605) cm-1. and absorption peaks of next functional groups: N-H amino group , C-H aromatic , C-H aliphatic, N=N azo group and SO2 sulfate group at : (3383 , 3087, 2978, (1462 and 1388) and (1660 and 1086)) cm-1 respectively.[34]The FT-IR spectrum of [Co(L)(H2O)Cl] complex displays the same absorption bands of that shown in previous complexes. N-H amino group, C-H aromatic, C-H aliphatic, N=N azo group and SO2 sulfate group at : (3384 , 3163, 2983, (1473 and 1388) and (1164 and 1087)) cm-1 respectively. Besides the band of coordinated water molecule which in turn observed at (3520 and 1613) cm-1[35]The FT-IR spectrum of [Cu(L)(H2O)Cl].[36]complex displays the same absorption bands that shown in previous complexes. N-H amino group, C-H aromatic, C-H aliphatic, N=N azo group and SO2 sulfate group at : (3385 , 3168, 2980, (1471 and 1389) and (1165 and 1088)) cm-1 respectively. Besides the band of coordinated water molecule which in turn observed at (3506 and 1612) cm-1. All the information data of the complexes have displayed in Table 4. Table 4. FT-IR spectral data of compounds. Compounds (H2O) aqua (NH) (C-H) aromatic (C-H) aliphatic (N=N) (SO2) Azo species-HL --- 3381 3091 2977 1448 1403 1160 1086 [Cr(L)(H2O)2Cl2] Octahedral 3652 1600 3388 3084 2977 1466 1387 1145 1091 [Fe(L)(H2O)2Cl2] Octahedral 3583 1605 3383 3087 2978 1462 1388 1160 1086 [Co(L)(H2O)Cl] Tetrahedral 3520 1613 3384 3163 2983 1473 1388 1164 1087 [Cu(L)(H2O)Cl] Tetrahedral 3506 1612 3385 3168 2980 1471 1389 1165 1088 IHJPAS. 36 (3) 2023 224 Figure 7. FT-IR spectrum of Azo-ligand (HL). Figure 8.FT-IR spectrum of Cr-complex. 3.6 Study of Thermogravimetric Analysis for Azo-ligand (HL)and complexes: DSC differential scanning calorimetry technique, defined as pyrolysis technique employed for estimation the amount of absorbed and released heat and for the thermal changes that happened for tested substance. Table 5, shows Ti/⁰C, Tf/⁰C, heat amount (ΔH) in J/g unit if it was exothermic or endothermic. Pyrolysis studies for Azo-ligand (HL)and itscomplexes were carried out depending on thermogravimetric analysis curve (TGA) by measuring the changes in masses of the substances under study relative to temperature when these substances obey to controlled thermal program in a specific time. The result curve isconsidered as thermogravimetric curve, which inform us about thermal stability, reaction rates, chemical structure and the thermal stability of the products as denoted in Table 6 in addition to each pyrolysis step occurred. TGA for HL in Figure 9 displays intensively three degradation steps, this technique can also demonstrate that, [Fe(L)(H2O)2Cl2] complex analyzes in four steps as illustrated in Figure 10that display the mechanism of its degradation, the critical temperature at which the maximal transformation of the complex occurs and the percentage of theoretical and calculated mass loss. It was found that, the IHJPAS. 36 (3) 2023 225 estimated mass loss is 87.181 % and the remnant is 12.819 % whereas the calculated mass loss is 87.3163 % and the remnant is 12.6387 % as FeO.[37]for [Cu(L)(H2O)Cl] complex, displays three degradation steps, the critical temperature at which the maximum mutation of complex carried out and the percentage of theoretical 85.835 % and the remnant is 14.165%, and calculated mass loss 84.786 % and the remnant is 15.214 % as CuO.[38]all the pyrolysis information has shown in Scheme 7. Scheme 7.Tentative decomposition reaction of Azo-ligand (HL) and complexs. Table 5. DSC records ofAzo-ligand (HL) and some complexes. Compound Ti / °C Tf/ °C ΔH J/g Max temp. °C and Type Azo-ligand (HL) [Fe(L)(H2O)2Cl2] [Cu(L)(H2O) Cl] 85 327.084 483.726 60 166.45 233.37 389.74 40 118.084 310.598 327.084 483.726 596.716 166.45 233.37 389.74 594.128 118.084 310.598 594.885 -13.3 -12.3 -7.9 -20 -3 1 -12.5 -6.7 -11.7 113.4 - endothermic 169.9 - endothermic 484.8 – endothermic 99.5- endothermic 263.3- endothermic 282.3- endothermic 87.7- endothermic 247.6- endothermic 349.7- endothermic IHJPAS. 36 (3) 2023 226 Figure 9. DSC & TGA curve of Azo-ligand (HL).Figure 10. DSC & TGA curve of Fe-complex. Table 6. TGA data of Azo-ligand (HL)and some complexes. Compound Ti / °C Tf/ °C TDTG max % Estimated (calc.) Assignment Mass loss Total mass loss Azo-ligand (HL) 85 327.084 483.726 327.084 483.726 596.716 200 401 541 16.8574 (17.5858) 43.0156 (42.7433) 32.6663 (33.7062) 92.52 (94.02) -CO -CS -C9H9N3O -C6H6N2O2 C2 Calculated:94.0353% final =5.9647%; Estimated 92.5393% final =7.4607% [Fe(L)(H2O)2Cl2] 60 166.45 233.37 389.74 166.45 233.37 389.74 594.128 98 200 308 490 11.348 (12.5177) 16.778 (16.0191) 41.874 (42.1926) 17.181 (16.6319) 86.4 (87.34) -2H2O - Cl -Cl -2CO -C12H9N4S -C5H5NO FeO Calc,: 87.3613% remnant =12.638%;Estimated 87.181% remnant =12.819% [Cu(L)(H2O) Cl] 40 118.084 310.598 118.084 310.598 594.885 180 240 453 4.075 (3.425) 21.094 (20.459) 60.666 (60.902) 25.169 (23.884) -H2O -Cl -CO,CS -C17H14N5O2 CuO Calc,: 81.51% remnant =18.49%;Estimated 80.51 % remnant =19.49% IHJPAS. 36 (3) 2023 227 3.7 Investigation of antioxidant activity The DPPH method was used to investigate antioxidant activity of mineral compounds. GA is employed as phenol-containing resource. In addition, in order to obtain a series of standards, penta various concentrated solutions are prepared. 1L of GA fluid with EtOH (for dilution benefits). 6- ml of 45g DPPH sol. we're adding onto 100-ul for each GA-solution. 30 min. later at room conditions, the absorptivity of the mixture was tested by UV-VIS _Spec. at 517 nm, Because of its accuracy, the largest number of researches are depending on such technique to estimate reactive oxygen-entities activity of DPPH-compounds. The lesser IC50 value, the higher degradation activity of reactive-oxygen entities. Depending on this conception, the order of our compounds follow as : ( GA<[Co(L)(H2O)Cl]>[Cr(L)(H2O)Cl]>[Fe(L)(H2O)2Cl2]>[Cu(L)(H2O)Cl]>Azo- ligand (HL)), [39-42]as shown in Table 7. Table 7. Reactive oxygen-entities activity of Azo- complexes. Compounds Standard deviation Mean Correlation coefficient IC50 (M) DPPH Coefficient of variation % GA 2.0846 93.5600 0.9966 -6.0304 2.2281 Azo-ligand (HL) 3.0663 45.7600 0.7632 1.6701 3.3521 [Cr(L)(H2O)2Cl2] 4.0035 18.3553 0.7665 0.2167 11.1843 [Fe(L)(H2O)2Cl2] 4.4427 20.7176 0.6425 0.3217 12.7842 [Co(L)(H2O)Cl] 2.7794 26.3751 0.8754 0.0561 3.3546 [Cu(L)(H2O)Cl] 12.4537 23.3992 0.7050 0.5435 12.6579 4. Conclusion The complexation operation between the next metal ions (Cr (III), Fe (III), Co (II) and Cu (II)) and the newly synthesized azo-species-HL was carried out successfully in the [1M:1azo] molar ratio. The complexes were characterized by FT-IR, Uv-Vis, (TGA, DSC for some complexes), and mass spectroscopic techniques. The spectroscopic techniques proved the structures of complexes, occurrence of coordinated water molecules in complexes depending on the obtained bands in (FT-IR) of the complexes; and degradation steps in thermal analysis, besides the obtained results from other techniques, as detailed in the manuscript. The experimental incomes and the elemental microanalysis results were so close to the calculated incomes. LC-Mss data manifest the complexation via the -NO moiety. References 1. Snigur, D.V.; Chebotarev, A.N.; Bevziuk, K.V. Acid–base properties of azo dyes in solution studied using spectrophotometry and colorimetry. Journal of Applied Spectroscopy2018, 85(1),21-6. 2. Li F, Zhang L, Hu C, Xing X, Yan B, Gao Y, Zhou L. Enhanced azo dye decolorization through charge transmission by σ-Sb3+-azo complexes on amorphous Sb2S3 under visible light irradiation. Applied Catalysis B: Environmental2019 1,240,132-40. 3. Mahmoud, W.H.; Omar, M.M.; Sayed, F.N. Synthesis, spectral characterization, thermal, anticancer and antimicrobial studies of bidentate azo dye metal complexes. Journal of Thermal Analysis and Calorimetry2016,124(2),1071-89. 4. Ahmad, K; Naseem, H.A.; Parveen, S; Shah, S.S.; Shaheen, S; Ashfaq, A; Jamil, J; Ahmad, M.M.; Ashfaq, M. Synthesis and spectroscopic characterization of medicinal azo derivatives and metal complexes of Indandion. Journal of molecular structure2019 ,15,1198,126885. IHJPAS. 36 (3) 2023 228 5. Mahmoud, W.H.; Sayed, F.N.; Mohamed, G.G. Synthesis, characterization and in vitro antimicrobial and anti‐breast cancer activity studies of metal complexes of novel pentadentate azo dye ligand. Applied Organometallic Chemistry2016,30(11),959-73. 6. Mallikarjuna, N.M.; Keshavayya, J; Maliyappa, M.R.; Ali, R.S.; Venkatesh, T. Synthesis, characterization, thermal and biological evaluation of Cu (II), Co (II) and Ni (II) complexes of azo dye ligand containing sulfamethaxazole moiety. Journal of Molecular Structure 2018 , 5,1165,28-36. 7. El-Bindary, A.A.; Mohamed, G.G.; El-Sonbati, A.Z.; Diab, M.A.; Hassan, W.M.; Morgan, S.M.; Elkholy, A.K. Geometrical structure, potentiometric, molecular docking and thermodynamic studies of azo dye ligand and its metal complexes. Journal of Molecular Liquids 2016, 1,218,138-49. 8. Mohammed, H. Synthesis, Identification, and Biological Study for Some Complexes of Azo Dye Having Theophylline. The Scientific World Journal 2021, 22. 9. Ispir, E.; Ikiz, M.; Inan, A.; Sünbül, A.B.; Tayhan, S.E.; Bilgin, S.; Köse, M.; Elmastaş, M. Synthesis, structural characterization, electrochemical, photoluminescence, antiproliferative and antioxidant properties of Co (II), Cu (II) and Zn (II) complexes bearing the azo-azomethine ligands. Journal of Molecular Structure2019, 15,1182,63-71. 10. El-Zomrawy, A.A. Selective, and sensitive spectrophotometric method to determine trace amounts of copper metal ions using Amaranth food dye. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2018, 5,203,450-4. 11. Lashanizadegan, M.; Ashari, H.A.; Sarkheil, M.; Anafcheh, M.; Jahangiry, S. New Cu (II), Co (II) and Ni (II) azo-Schiff base complexes: Synthesis, characterization, catalytic oxidation of alkenes and DFT study. Polyhedron 2021, 15,200,115148. 12. Kyei, S.K.; Akaranta, O.; Darko, G. Synthesis, characterization and antimicrobial activity of peanut skin extract-azo-compounds. Scientific African 2020, 1,8, e00406. 13. Mahdy, A.R.; Ali, O.A.; Serag, W.M.; Fayad, E.; Elshaarawy, R.F.; Gad, E.M. Synthesis, characterization, and biological activity of Co (II) and Zn (II) complexes of imidazoles-based azo-functionalized Schiff bases. Journal of Molecular Structure 2022, 5,1259,132726. 14. Kyhoiesh, H.A.; Al-Adilee, K.J. Synthesis, spectral characterization, antimicrobial evaluation studies and cytotoxic activity of some transition metal complexes with tridentate (N, N, O) donor azo dye ligand. Results in Chemistry 2021, 1,3,100245. 15. Mandour, H.S.; Abouel-Enein, S.A.; Morsi, R.M.; Khorshed, L.A. Azo ligand as new corrosion inhibitor for copper metal: Spectral, thermal studies and electrical conductivity of its novel transition metal complexes. Journal of Molecular Structure2021 , 5,1225,129159. 16. Mallikarjuna, N.M.; Keshavayya, J. Synthesis, spectroscopic characterization and pharmacological studies on novel sulfamethaxazole based azo dyes. Journal of King Saud University-Science 2020 1,32(1),251-9. 17. Reda, S.M.; Al-Hamdani, A.A. Synthesis, Characterization, Thermal Analysis and Bioactivity ofSome Transition Metals Complexes with New Azo Ligand. Chemical Methodologies2022, 6(6), 475-493. 18. Alothman, A.A.; Albaqami, M.D.; Alshgari, R.A. Synthesis, spectral characterization, quantum chemical calculations, thermal studies and biological screening of nitrogen and oxygen donor atoms containing Azo-dye Cu (II), Ni (II) and Co (II) complexes. Journal of Molecular Structure 2021 , 5,1223,128984. 19. Al-Daffay, R.K.H.; Al-Hamdani, A.A.S. Synthesis, Characterization, and Thermal Analysis of a New Acidicazo Ligand's Metal Complexes. Baghdad Science Journal 2022, 19(3), 121-133. IHJPAS. 36 (3) 2023 229 20. Kadhim, A.A.; Kareem, I.K.; Ali, A.A. Synthesis and Spectral Identification of New Azo-Schiff base Ligand Derivative from Aminobenzylamine and its Novel Metal Complexes with Cu (II), Zn (II) and Cd (II). Annals of the Romanian Society for Cell Biology 2021 ,25,25(6),4596-607. 21. Mahdi, M.A.; Jasim, L.S.; Mohamed, M.H. Synthesis, Spectral and Biological Studies of Co (II), Ni (II) and Cu (II) Complexes with New Heterocyclic Ligand Derived from Azo-Dye. Pharmaceutical reviews 2021 ,1,12,426-34. 22. Witwit, I.N.; Farhan, H.M.; Motaweq, Z.Y. Preparation of Mixed ligand Complexes of Heterocyclic Azo Quinoline Ligand and Imidazole Molecule with Some of Divalent Transition Ions and their Biological Activity Against Multi Drug Resistance Pathogenic Bacteria. InJournal of Physics: Conference Series 2021,1,1879 (2), 022064. 23. Rahman, M.; Haque, T.M.; Sourav, N.S.; Rahman, S.; Yesmin, S.; Mia, R.; Al Noman, A.; Begum, K. Synthesis and investigation of dyeing properties of 8-hydroxyquinoline-based azo dyes. Journal of the Iranian Chemical Society 2021, 18(4),817-26. 24. El-Seify, F.A.; El-Dossoki, F.I.; Gouda, M.M. Spectrophotometric and conductometric studies of new synthesized azo derived from pyrazole as analytical reagents. Chemical Papers 2021, 75(11),5917-27. 25. Wannas, N.M.; Al-Hamdani, A.A.S.; Al-Zoubi, W. Spectroscopic characterization for new complexes with 2,2'- (5,5-dimethylcyclohexane-1,3- diylidene)bis(azan-1-yl- 1- ylidene)dibenzoic acid. Journal of physical organic chemistry 2020, 33(11), 1-12. 26. Sönmez, M.; Sogukomerogullari, H.G.; Öztemel, F.; Berber, İ.Synthesis and biological evaluation of a novel ONS tridentate Schiff base bearing pyrimidine ring and some metal complexes, Medicinal Chemistry Research 2014, 23 (7), 3451–3457. 27. 27.Abdulrazzaq, A.G.; Al-Hamdani, A.A. Ni2+, Pt4+, Pd2+, and Mn2+ Metal ions Complexes with Azo Derived from Quinolin-2-ol and 3-amino-N-(5-methylisoxazol-3-yl) Benzenesulfonamide: Synthesis, Characterization, Thermal Study, and Antioxidant Activity. Baghdad Science Journal.2023,20 (4), 1-17. 28. Al-Daffay, R.K.; Al-Hamdani, A.A. Synthesis and Characterization of Some Metals Complexes with New Acidicazo Ligand 4-[(2-Amino-4-Phenylazo)-Methyl]-Cyclohexane Carboxylic Acid. Iraqi Journal of Science2022 ,31,3264-75. 29. Abdulrazzaq, A.G.; Al-Hamdani, A.A.Some Metal Ions Complexes With Azo [4-((8- hydroxyquinolin-7- yl)-N(4-methylisoxazol-3-yl)benzenesulfonamide] Synthesis, Characterization, Thermal Study and Antioxidant Activity.journal of Medicinal and Chemical Sciences2023,6 (2), 236-249 30. Al-Daffay, R.K.; Al-Hamdani, A.A. Synthesis, Characterization, and Thermal Analysis of a New Acidicazo Ligand's Metal Complexes. Baghdad Science Journal 2022,19(3),121-33. 31. Al Zoubi, W.; Vian, Y.J.; Veyan, T.S.; Al-Hamdani, A.A.S.; Suzan, D.A.; Yang, Gon Kim et al. Synthesis and bioactivity studies of novel Schiff bases and their complexes. Journal of physical organic chemistry 2019, e4004, 1-7. 32. Suleman, V.T.; Al-Hamdani, A.A.S.; Ahmed, S.D.; Jirjees, V.Y.; Khan, M.E.; Adnan, Dib et al. Phosphorus Schiff base ligand and its complexes: Experimental and theoretical investigations. Applied organometallic chemistry 2020, 34(4), 1-16. 33. Abdulridha, M.Q.; Al-HamdaniA.A. Synthesis, Characterization and Thermal Study of Some New Metal Ions Complexes with a New Azo 2-((2-(1H-Indol-2- yl)ethyl)diazinyl)-5- aminophenol2023, Journal of Medicinal and Chemical Sciences6 (1),121-131 https://scholar.google.com/citations?view_op=view_citation&hl=en&user=dbjLJZUAAAAJ&cstart=20&pagesize=80&citation_for_view=dbjLJZUAAAAJ:86PQX7AUzd4C https://scholar.google.com/citations?view_op=view_citation&hl=en&user=dbjLJZUAAAAJ&cstart=20&pagesize=80&citation_for_view=dbjLJZUAAAAJ:86PQX7AUzd4C https://scholar.google.com/citations?view_op=view_citation&hl=en&user=dbjLJZUAAAAJ&cstart=20&pagesize=80&citation_for_view=dbjLJZUAAAAJ:86PQX7AUzd4C https://scholar.google.com/citations?view_op=view_citation&hl=en&user=dbjLJZUAAAAJ&cstart=20&pagesize=80&citation_for_view=dbjLJZUAAAAJ:PVjk1bu6vJQC https://scholar.google.com/citations?view_op=view_citation&hl=en&user=dbjLJZUAAAAJ&cstart=20&pagesize=80&citation_for_view=dbjLJZUAAAAJ:PVjk1bu6vJQC https://scholar.google.com/citations?view_op=view_citation&hl=en&user=dbjLJZUAAAAJ&cstart=20&pagesize=80&citation_for_view=dbjLJZUAAAAJ:PVjk1bu6vJQC IHJPAS. 36 (3) 2023 230 34. Al Zoubi, W.; Al‐Hamdani, A.A.S.; Susan, D.A.; Hassan, M.B.; Al‐Luhaibi, R.S.A.; Adnan, Dib.; Young, G.K. Synthesis, characterization, and antioxidant activities of imine compounds. Journal of physical organic chemistry2018, e3916, 1-9. 35. Nakamoto, K. Infrared and Raman Spectra of Inorganic and Coordination Compounds; 5th ed. Wiley-Interscience, New York, 1997; Part A. P. 7-12. 36. Kareem, M.J.; Al-Hamdani, A.A.S.; Ko, Y.G.; Al Zoubi, W.; Mohammed, S.G. Synthesis, characterization, and determination antioxidant activities for new Schiff base complexes derived from 2-(1H-indol-3-yl)- ethylamine and metal ion complexes. Journal of molecular structure 2021, 1231(5), 1-30. 37. Kareem, M.J.; Al-Hamdani, A.A.S.; Jirjees,V.Y.; Khan, M.E.; Allaf, A.W.; Al Zoubi, W. Preparation, spectroscopic study of Schiff base derived from dopamine and metal Ni (II), Pd (II), and Pt (IV) complexes, and activity determination as antioxidants. Journal of physical organic chemistry 2020, 34(3), 1-15. 38. Al Zoubi, W.; Al-Hamdani, A.A.S.; Ko, Y.G. Schiff bases and their complexes: Recent progress in thermal analysis. Separation Science and Technology 2017, 52(6), 1052- 1069. 39. Hamza, I.S.; Mahmmoud, W.A.; Al-Hamdani, A.A.; Ahmed, S.D.; Allaf, A.W.; Al Zoubi, W. Synthesis, characterization, and bioactivity of several metal complexes of (4-Amino-N-(5- methyl-isaxazol-3-yl)-benzenesulfonamide). Inorganic Chemistry Communications 2022 ,6,109776. 40. Al Zoubi, W.; Mohamed, S.G.; Al-Hamdani, A.A.S.; Mahendradhany, A.P.; Ko, Y.G. Acyclic and cyclic imines and their metal complexes: recent progress in biomaterials and corrosion applications. RSC advances 2018,8(41), 23294-23318. 41. Mohamed, W.N.; Al-Hamdani, A.A.S.; Al Zoubi, W.Spectroscopic characterization for new complexes with 2, 2′-(5, 5-dimethylcyclohexane-1, 3-diylidene) bis (azan-1-yl-1-ylidene) dibenzoic acid. Journal of physical organic chemistry 2020,33(11), e4099. 42. Turan, N.; Buldurun, K.; Adiguzel, R.; Aras, A.; Turkan, F.; Bursal, E. Investigation of spectroscopic, thermal, and biological properties of FeII, CoII, ZnII, and RuII complexes derived from azo dye ligand. Journal of Molecular Structure 2021, 15,1244,130989.