By condensing 2‐aminobenzothiazole with 2‐hydroxy‐1‐naphthaldehyde, 2‐hydroxybenzaldehyde, 4‐methoxybenzaldehyde, 4‐hydroxybenzal‐dehyde, benzaldehyde and 4‐dimethylaminobenzaldehyde, and five Schiff bases Ia‐Ie are prepared. Also, two Schiff bases IIa and IIb are prepared by condensation of 2‐amino‐3‐hydroxypyridine with 2‐hydroxy‐1‐naphthaldehyde and 2‐hydroxybenzaldehyde. The 1H NMR, IR and UV/Vis spectra of these seven Schiff bases are investigated. The signals of the 1H NMR spectra as well as the important bands in the IR spectra are considered and discussed in relation to molecular structure. The UV/Vis absorption bands in ethanol are assigned to the corresponding electronic transitions and the electronic absorption spectra of Schiff bases Ib and IIb are studied in organic solvents of different polarities. The UV/Vis absorption spectra of 2‐amino‐3‐hydroxypyridine Schiff bases IIa and IIb are investigated in buffer solutions of different pH values containing 5% (v/v) methanol, and the results are utilized for the determination of pKa and ΔG* of the ionization of the phenolic OH‐groups. The fluorescence spectra of IIa and IIb are studied in organic solvents of different polarities.
The obtained spectral results are confirmed by some molecular calculations using the atom super position and electron delocalization molecular orbital theory for the Schiff base IIb.
A new azo dye ligand (abbreviated as H 3 L) derived from coupling of sulfafurazole diazonium salt with 2,4-dihydroxybenzaldehyde was prepared and characterized applying different spectroscopic and analytical techniques.The novel nanosized trivalent Cr and Fe alongside with divalent Mn, Co, Ni, and Cd complexes with H 3 L have been synthesized for further promising pharmaceutical uses. All complexes were totally characterized by investigating various analytical and spectral tools such as microanalysis, FT-IR, 1 H NMR, UV-Vis, powder XRD, and TEM spectra as well as magnetic moment and molar conductance measurements. Microanalysis, TGA, and conductance studies confirmed the formation of all metal complexes in 1:1 (L: M) molar ratio with covalent mode. The FT-IR and 1 H NMR investigation asserted the chelation of H 3 L to different metal ions through azo nitrogen and phenolic deprotonated hydroxy oxygen in the o-position. UV-Vis, ESR, and magnetic moment studies revealed octahedral geometry around Cr and Fe ions, whereas Mn, Co, Ni, and Cd complexes displayed tetrahedral configurations. XRD patterns and TEM images proved homogeneous distribution over the chelates surfaces and nanometric size of complexes particles. Molecular modeling was used to optimize the complexes' geometric structure showing good harmonity with the experimental results. The antifungal and antibacterial efficiencies were strongly enhanced upon complex formation. Cr(III) and Ni(II) complexes showed the strongest and promising anticancer activities (IC 50 = 7.64 and 6.99 μg/ml) among the tested compounds, whereas Cd(II) complex showed moderate anticancer efficiency (IC 50 = 12.10 μg/ml), compared with the 5-fluorouracil (applied standard drug) with IC 50 = 6.44 μg/ ml.
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