Synthesis, characterization and investigation of tautomeric, potentiometric and antimicrobial properties of a novel unsymmetric Schiff base and its Fe(III) and Ni(II) complexes

Abstract A new unsymmetric Schiff base [(2OH)R-CH=N-(C6H4)-CH=N-R'(2OH) R=phenyl, R' = naphthyl] with its Fe(III) and Ni(II) complexes were synthesized by a two step method. Diimine Schiff base and its complexes were characterized by elemental analysis, mass spectra, IR, 1H/13C-NMR spectra, TGA analysis, electronic and magnetic measurements. The phenol-imine and keto-amine tautomerism of the unsymmetric Schiff base was investigated with NMR techniques and UV-visible spectra in different solvents. Also, the protonation constants of the ligand and the stability constants of its Ni(II) and Fe(III) complexes were determined potentiometrically in 1:1(v/v) ethanol-water mixture at an ionic strength of 0.5 mol·L-1 KCl and at 25.0 ± 0.1 oC. The antifungal, antimicrobial activities and the minimum inhibitory concentration (MIC) values of the compounds were evaluated against Escherichia coli (0157:H7), Micrococcus luteus (NRRLB 4975), Bacillus cereus (RSKK 863) and Candida albicans (ATCC 16231). 

Novel unsymmetric diimines: Synthesis and biological evaluation against pathogenic microorganisms

In this research study, three new unsymmetric diimines (3a-3c) were prepared using a two-step process. The synthesized unsymmetric tetradentate diimines were elucidated by FT-IR, 1H-NMR, LC-MS, elemental analysis techniques. The antimicrobial and the antifungal properties of newly synthesized unsymmetrical diimines (3a-3c) and previously reported by one of us unsymmetrical diimines (4a-4c) were evaluated against L. monocytogenes 4b, B. cereus sp., S. typhi H, Br. abortus, S. epidermis sp., M. Luteus sp., E. coli, P. putida sp. Sh. dys. typ. 7 ve C. albicans. 3b, 3c, 4a and 4c are showed the highest antimicrobial activity against B.cereus sp. 3a and 4b are exhibited the highest activity against S.epidermis sp. and Br. abortus, respectively. In addition, all unsymmetrical diimines are showed high antifungal activity against C. albicans. © 2020 by SPC (Sami Publishing Company)2-s2.0-8510635710

Novel unsymmetric diimines: Synthesis and biological evaluation against pathogenic microorganisms

In this research study, three new unsymmetric diimines (3a-3c) were prepared using a two-step process. The synthesized unsymmetric tetradentate diimines were elucidated by FT-IR, 1H-NMR, LC-MS, elemental analysis techniques. The antimicrobial and the antifungal properties of newly synthesized unsymmetrical diimines (3a-3c) and previously reported by one of us unsymmetrical diimines (4a-4c) were evaluated against L. monocytogenes 4b, B. cereus sp., S. typhi H, Br. abortus, S. epidermis sp., M. Luteus sp., E. coli, P. putida sp. Sh. dys. typ. 7 ve C. albicans. 3b, 3c, 4a and 4c are showed the highest antimicrobial activity against B.cereus sp. 3a and 4b are exhibited the highest activity against S.epidermis sp. and Br. abortus, respectively. In addition, all unsymmetrical diimines are showed high antifungal activity against C. albicans. © 2020 by SPC (Sami Publishing Company)2-s2.0-8510635710

Novel hydrazone derivatives and their tetracoordinated metal complexes

New aroylhydrazone derivatives and their Co(II), Ni(II) and Cu(II) complexes have been synthesized and characterized by means of elemental analyses, molar conductances and magnetic measurements as well as electronic spectra, IR spectra, 1H NMR spectra, 13C NMR spectra and LC mass spectra. Ni(II) complexes were found to have general compositions [ML], where L = 2,6-dipiperidino-4-(2-hydroxybenzylidene hydrazino)-1,3,5-s-triazine; 2,6-dipiperidino-4-(5-bromo-2-hydroxybenzylidenehydrazino)-1,3,5-s-triazine, while other complexes have composition [ML2] (M = Co2+ or Cu2+). The infrared spectra indicate the coordination of imino nitrogen and phenolic oxygen atoms. Tetracoordinated structures are proposed for the Co(II) Ni(II) and Cu(II) complexes on the basis of magnetic evidence and electronic spectra

Synthesis of novel polymers containing Schiff base as potential antimutagenic and antimicrobial agents

In this research study, two novel polymers including Schiff base were prepared by condensation reaction of polystyrene-A-NH2 with 5-nitro-2-thiophenecarboxaldehyde/or 5-(2-nitrophenyl)-2-furancarboxaldehyde. The synthesized polymers were evaluated using the elemental analysis, infrared spectroscopy (IR), gel permeation chromatography (GPC), thermal gravimetric analysis (TG/DTA). In addition, the antimicrobial and antimutagenic study of the polymers were reported. The antibacterial and antifungal activity were investigated using the diffusion method against pathogenic bacterial strains. PA-TC and PA-FC polymers exhibited the highest antimicrobial activity against the S. typhi H. and P. vulgaris, respectively. PA-FC polymer revealed the highest antifungal activity against C. albicans. The antimutagenic effects were evaluated using the sister chromatid exchange (SCE) and micronucleus (MN) methods against the sodium azide (NaN3) in human lymphocyte cells. The results demonstrated that the PA-FC polymer have strong antimutagenic properties, especially in the concentration of 20 µg/mL. © 2020 by SPC (Sami Publishing Company)2-s2.0-8510636860