Synthesis, Analytical and Theoretical Studies of (Z)-4-amino-3-hydroxy-2-((4-(N-(5-methylisoxazol-3-yl)Sulfamoyl)Phenyl)Diazenyl)Naphthalene-1-Sulfonic Acid

New azodye that characterize (Z)-4-amino-3-hydroxy-2-((4-(N-(5-methylisoxazol-3-yl) sulfamoyl) phenyl)diazenyl)naphthalene-1-sulfonic acid (1) was synthesized. The azodye has been characterized by IR, visible spectra and elemental (CHN) analysis. The results of visible spectra which recorded in the range (360-6540) nm were showed that the maximum wave length (λmax) of azodye was 500 nm. Analytical studies carried on the dye, the results of the solvent effect were showed high solubility in ethanol and water. But, the results of the pH effect in a range of buffer solution were gave three isopestic points. The ionization constant (pKa) and protonation constant (pKb) were calculated by using the half height method. The results were showed that the pKp1 and pKp2 of each nitrogen atom and pKa of OH-group were equal to 2.5, 4.5 and 8.5 respectively. Theoretical studies also carried on azodye (1). The actual and optimal bonds length of -N=N- was equal to 1.248 in each. Though, internal coordinate mechanics (ICM) of (1) was showed that the angle type in most of atoms was dihedral. But, the R and S configuration were observed in other atoms in the structure of azodye. The results also indicated that the torsion angles (ψ) of (1) were variable. High close contacts of atoms were observed in the structure of azodye. The molecular mechanics (MM2) properties was intended for (1), the results showed that the stretch, bend, stretch-bend, torsion, non-1,4 VDW, 1,4 VDW and the total energy were equal to 61.0809, 627.0240, -1.6517, 179.0634, 4686.8146, 33.0379 and 5585.3692 kcal/mol respectively. High VDW interactions of this molecule was observed, due to the results of dipole/dipole were not computed. Thus, the result of MM2 minimization for azodye (1) was showed high VDW interactions of this molecule higher than before the minimization, due to the result of dipole/dipole was also not computed. The high steric energy (1235.782) was affecting the results of minimization. However, the results of the molecular mechanics force field (MMFF94) energy and gradient for azodye (1) were showed that the total energy and RMS gradient were equal to 26223.422 kcal/ mol and 9113.745 respectively. Further, the results of MMFF94 minimization and MMFF94 minimization/sampling of azodye (1) were showed that the minimization was attended successfully using this method. Keywords: Internal coordinate, Molecular mechanics, Azodye

Synthesis and Biological Activity of Three Novel Azo Dyes

The azo dyes that named, (E)-4-((2-nitrophenyl) diazenyl) benzene-1,3-diol (1), (E)-4- ((3-nitrophenyl) diazenyl) benzene-1,3-diol (2) and (E)-4-((4-nitrophenyl) diazenyl) benzene-1,3-diol (3) were synthesized and then characterized using IR, UV-visible spectrum. These results were compared with that obtained by ChemBio 3D Ultra - [Chem3D XML] Gaussian Interface and were seems to be identical. Then, the antimicrobial activity of each azo dye was carried out against two bacterial strains: Staphylococcus aureus NCTC 6571, and Escherichia coli ATCC 25922, and fungal strains of Candida albicans using Agar-well diffusion method. The results were showed that the three azo dyes were biologically active and the best reactivity was observed in (2). Though, the biological activity of (1) with NO2 group in ortho- position remained reasonable against Candida albicans. But, the effect of (1) was resisted by Staphylococcus aureus and Escherichia coli. However, the (2) and (3) with substituted NO2 group in meta- and para- positions respectively were showed better reactivity’s than (1) towered Candida albicans and Staphylococcus aureus. Further, the Gaussian interface properties and the conformational analysis of (1), (2) and (3) were intended. The results were indicated that the variations in the properties of each azo dye and their conformational energies of generated conformers can affect their biological activity afterward. Keywords: key words, Azo dyes, Staphylococcus aureus, Escherichia coli, Candida albicans, Agar-well diffusion method, Antimicrobial activit