Synthesis, Characterization, DFT and Antibacterial, Azo Ligand Derived From 2-Amino pyrimidine With Antipyrine Mixed ligand Complexes involving 1,10- phenanthroline

A new heterocyclic ligand (1,5-dimethyl-2-phenyl-4-(pyrimidin-2- yldiazenyl)-1,2-dihydro-3H-pyrazol-3-one, was synthesized by the diazotization of 2- (chlorodiazenyl)pyrimidine, and coupling with antipyrine to produce a new azo dye in an alkaline alcoholic solution under optimized experimental conditions (Azo-pyrm-Ap) (pyrimidin-2-yldiazenyl) ligand. and react with 1,10-phenanthroline, Ferric(II), Cobalt(II), Nickel(II), Copper(II), Zink(II), and Merrcury(II) ions were used to build the structure of mixed-ligand Tatradentate complexes. They confirmed all that by 1H- NMR,UVevisb, Fesem, XRD (DSC-TG) thermal analysis, Inferred- IR Magnetic susceptibility, The(C.H and N) analysis, molar conductance, and atomic absorption are all examples of spectroscopic techniques. The isolated solid complexes have been to have identified the formula in general [M (L)(phen) Cl] and [M (L)(phen)(H2O)] Cl, For prepared complexes, conductivity measurements revealed a [1:1] electrolyte. for Fe(II) and non-electrolyte for the Ni(II), Co(II), Zn(II), Cu(II), and, Hg(II) complexes. assemblages According to the spectral and analytical results, this ligand acts as a Bidentate chelating agent, with all metal ions having a coordination number of six. Finally, biological activity of the synthesized ligand and metal complexes against bacterial species was evaluated., Staphylococcus aureus is a Gram positive bacteria, and Escherichia coli, Pseudomonas aereuguinosa, and Klebsiella pneumoniaea are Gram negative bacteria. and it was found that these compounds have different inhibitory activity on bacteria growth.


Formulation of azo dye ligand (Azo-pyrim-Ap)
By using the flwoing methods, the Pyrimidzolyl azo dye ligand (Azo-pyrm-Ap) has been synthesized by the diazotization coupling reaction. Khalid J. AL-Adilee et al. [22] . with some modi-fications (Scheme 1) by dissolving 1.635gm ,(0.0172mol) of 2-amino Pyrimidine in a mixture of 5.5 ml distilled water and 5 mL concentrated hydrochloric acid, cooled and stirred continuously until the temperature was reached (0-5) C, and then added a solution of sodium nitrite made from the dissolved sodium nitrite 1.18gm (0.0172mol) in 5 ml distilled water was applied drop by drop to a solution of 2-amino Pyrimidine in an ice bath at 0°C. The resulting diazonium chloride solution was added drop by drop to a solution consisting of 3.237gm (0.0172mol) Antipyrine,) solved in 18 ml ethanol and 18 ml 6% After adding the entire amount of NaOH, leaving the mixture to stabilize for 2 hours, followed by adding By changing the pH of the solution to pH = 6, leaving the precipitate overnight, and then filtering and washing it several times with distilled water, 200 ml of distilled water and cold was stable precipitate was formed. and a 10ml ethanol solution to clear any unreacted products The result was 80 % Green crystals with a melting point of 150-153 degrees Celsius. IR, 1H-NMR, C.H and N, UV-Visb are used to transform the structure of the azo dye ligand (Azopyrm-Ap).

Formulated of metal complexes
The metal transition complexes were made by dissolving 0.882gm (0.003mol) in 30 ml ethanol and then adding a stoichiometric volume of [1M:1 L ] mole ratio to metal chloride (0.003 mol) drop wise with stirring at pH =7.0 in buffer solution (ammonium acetate). M= Co(II), Ni(II), Fe(II), Cu (II) , Zn(II), and Hg (II) ligand dissolved in 25 ml buffer solution. The reaction mixture was held at a constant temperature for 45-50 minutes, [22]. After a period of refluxing 1 h, (0.003 mol) of 1,10-phenanthroline was added to the solution. The reaction was heated for an additional 2 h The metal transition complexes are filtered out and distilled water is used to wash the solution. becomes colorless, after which they are coated with glossy stratum and left over night. For those ligands and their metal chelate complexes, (Table 1) shows a a set of physical and analytical properties results [23,24]. The heterocyclic azo dye ligand (Azo-pyrm-Ap) developed green crystals, but the Depending on the metal ion, the metal chelate complexes obtained were of different colors. The ligand and its complexes are stable in air at room temperature. Some organic solvents, such as ethanol, methanol, acetone, CHCl 3 , DMF, DMSO, alkaline solutions, and strongly acidic solutions, are soluble in it.

Molar conductivity measurements
The molar conductivity of the prepared metal complexes was measured at room temperature in DMF as a solvent with a concentration of (10 -3M). The conductivity values are described in the table below ( Table 3). The molar conductivity of the Fe(II) complex indicates that it was an electrolyte with a [1: 1] ratio. The ionic nature of the Ni(II), Cu(II), Zn(II), and Hg (II) complexes was demonstrated Used a silver nitrate (AgNO3) solution, which resulted in a white silver chloride precipitate (AgCl) [25], However, because of the low molar conductivity of these complexes indicated their nonionic structure and nonelectrolyte nature [26,27].  Table 3. shows the infrared spectra of the azo dye ligand (Azo-pyrim-Ap) and The metal transition complexes with Co(II), Ni (II), Fe(II), Zn(II), Cu(II), and Hg(II). ions using a KBr disc in the range (4000-400) cm -1 .

1 H-NMR spectra
The 1 HNMR spectrum of ligand (Azo-pyrim-Ap )was recorded in (DMSO-d 6 ) and spectrum was shown in (Fig.3). 1 HNMR spectrum of the Azo dye ligand shows peak at (7.34 -7.57 δ ppm, multiplet 6H) aromatic The ligand also shows the following signals: (2.08 δppm C-CH 3 ), (3.37 δppm -N-CH 3 ) of Antipyrine group [12,15] .(8.28δ ppm-1H duplet N-CH=CH) of Pyrimidine group respectively. and, All of the protons were found to be in the correct location. The results of these studies add to the support for the mode of bonding discussed in the (C.H. and N) and IR spectra.

3.5.Magnetic measurements
The. Fe(II)., complex has a magnetic moment of 5.21 which corresponds to the stated value for octahedral, Co (II). The magnetic moment of the complex is 4.32BM (Table 3), which is consistent with previous reports for octahedral Co(II) complexes. The magnetic moment value of the current Ni(II) complex is 3.08BM, which is within the range of 2.9-3.3 BM [28,29,30], indicating an octahedral environment. The magnetic moment of the Cu(II) complex is 1.93BM, which is higher than the spin-only value of 1.73BM for one unpaired electron, monomeric, and compatible with a distorted octahedral geometry. The Zn(II) and Hg(II) complexes were diamagnetic and had an octahedral geometry, according to their empirical formulae [30].

3.6.Electronic spectra
spectrums of ligand (Azo-pyrim-Ap) and its complexes. Fe(II),Co(II),Ni(II) Zn(II) and Hg(II) in DMF [10 -3 M] The geometric structures of the complexes are determined using electronic spectra and magnetic measurements. (Table 3). The electronic spectrum of Fe(II) complex displays weak absorption band at 12822cm -1 corresponding to 5 T 2 g → 5 Eg, Co(II) complex . The electronic spectrum of Co(II) complex displays weak absorption bands at 12985 cm -1 , 14925 cm -1 and 22728 cm -1 characteristic of octahedral geometry corresponding to 4  Co(II) complex which supports octahedral geometry for the complex. The Ni(II) complex also exhibits three weak absorption bands at 13157 cm -1 ,16528 cm -1 and 23255 cm -1 assignable to 3 A 2 g → 3 T 2 g(F), 3 A 2 g(F) → 3 T 1 g(F), 3 A 2 g(F) → 3 T 1 g(P) which are characteristic of octahedral geometry. The Cu(II) complex depicts a broad band in the region 13560 cm -1 to 17760 cm -1 with maximum at 15650 cm -1 assignable to 2 Eg → 2 T 2 g in its spectrum, the broadness of the band may be due to octahedral geometry

XRD analysis
In the X'pert high score software kit, the XRD powder pattern is processed (Fig.5). The PXRD pattern for the Fe(II) complex was subjected to a check matching procedure, which revealed a match with a copper compound JCPDS powder diffraction file. PDF No 991218. (Table 4) The pattern is a tetragonal crystal system with a = b = 10.19, c = 5.468, = = = 90, lattice = body centred, and space group is 14/mmm(139), K is a constant (0.94 for Cu grid), is the Bragg diffraction angle, is the X-ray wavelength (1.5406 A), and is the full-width at half-maximum (FWHM) of prominent intensity peak, intensity (percentage), and integrated intensity [30,31].

SEM analysis
The ligand and its complexes had different morphologies, as shown in (Fig.6). The

Thermal studies
The (Azo-pyrim-Ap) Ligand and Its Complexes. [Fe (L)(pheon)(H 2 O)Cl]Cl and [Co (L) ( pheon)Cl 2 ] The decomposition occurs in at least six major detectable steps; each step does not refer to a single process in general, but rather to three data obtained that support the proposed structure and indicate the Ligand and its complexes Fe(II) and Co(II) go through. [30.31,22]

3.10.Computational study
The studied compounds are subjected to a computational analysis to determine their reactivities and geometrical parameters.. The perspective of Gauss The structures are described using 4.1 [31]. The structures of the ligand and all of its metal complexes are optimized using the 6-311++G(d,p) basis set at the B3LYP [32] level of theory. 6-311++G(d,p) is a broad basis collection that includes diffused and polarized wave functions to account for the properties of ionic species with heavy atoms such as N. Chemcraft software [33]. is used to visualize the studied compounds' optimized geometry. To ensure that the structures are real minima, the harmonic frequency calculation is also performed at the same level of theory. The results are carried out without any symmetry constraints, using the software's default convergence criteria.. The Gaussian 03 routine is used to perform the molecular calculations in this paper. Coordination compounds and organic molecules have both derived from this computational approach. Chemical potential is defined by DFT as the first derivative a measure of energy in terms of the number of electrons where (E) is the maximum energy of the system, (N) is the number of electrons in the system at constant external strain, and Chemical hardness (n) is half of the second derivative of energy with respect to the number of electrons, so it is the first derivative of energy with respect to the number of electrons.  [32].
However, in most cases, chemical potential(µ) and chemical hardness(n) are measured in terms of ionization potential(IP) and electron affinity(EA), and thus [33].
According to Koopman's theorem, IP and EA are compared to the energies of the highest occupied molecular orbital (EHOMO) and the lowest occupied molecular orbital (ELUMO). EA = -E LOMO, and IP = -E HOMO Electrophilicity was proposed by Parr and coworkers as a measure of a compound's electrophilic ability. Electrophilicity can be described as Table-6

4.Antibacterial study
The investigated compounds' in-vitro biological screening effects were checked against bacteria using the The experiment was repeated three times under identical conditions using the disc diffusion method and nutrients agar as the medium. Table 6 summarizes the results, with DMSO serving as a negative control and Amoxicillin acting as a positive normal.

Table 7. The synthesized compounds' minimum inhibitory concentrations against the growth of four bacteria (MIC in µg/mL)
The zone of inhibition region for metal chelates is much greater than the ligand, as shown in Table 6. Chelation theory may describe the increased activity of metal chelates in this way. Due to the overlap of the ligand orbitals, the polarity of the metal ion would be decreased to a greater degree during chelation. It also promotes the delocalization of π -electrons. over the entire chelate ring and increases the complexes' lipophilicity [34,35] This increased lipophilicity causes the cell's permeability barrier to break down, slowing down normal cell processes.

Conclusions
The authors of this paper describe the synthesis and spectral characterization of a new hetroarylazo dye derived from 2-aminopyrimidine with Antipyrine (Azo-pyrim-Ap) and its metal complexes with Fe(II),Co(II),Ni(II),Cu(II),Zn(II), andHg(II) ions. Analytical, physical, and spectral data from the chalet complexes, such as IR, 1H-NMR, UV-Visb., and Xrd, 14 revealed the ligand (Azo-pyrim-Ap) mixed ligand with(N,N) from free ligand 1,10phenanthroline, acts as Bidentate N, O coordination involving one of the azo nitrogen which is the farthest of Azo group between pyrazole ring and Pyrimidine ring, and the oxygen of Carbonyl group of pyrazole ring. Both complexes have been proposed to have an octahedral geometry. The Fe(II) complex is ionic, resulting in a [1:1] electrolyte, but the Co(II),Ni(II),Cu(II),Zn(II), and Hg(II) complexes are non-ionic. XRD and SEM studies revealed that the ligand and its complexes had different structures and morphologies. TG-DSC diagrams were used to investigate the thermal stability of ligand and its complexes, and it was discovered that the Theoretical Calculation (HOMO and LOMO)Orbitals and thermal stability were both successful in the complexes. The prepared complexes have important applications in industrial fields like dyes, as well as medical fields like pharmacology, toxicology, and biochemistry.