Synthesis, characterization and antimicrobial activity of 3,5-di-tert-butylsalicylaldehyde-S-methylthiosemicarbazones and their Ni(II) complexes

Abstract

Ni(II) complexes were prepared by the reactions of 3,5-di-tert-butylsalicylaldehyde-S-methylisothiosemicarbazone (L) with salicylaldehyde or 2-hydroxy-1-naphthaldehyde in the presence of NiCl 2 Á6H 2 O. The complexes and starting material L were characterized by physicchemical analysis and spectroscopic techniques such as 1 HNMR, 13 CNMR, IR and UV-VIS. Antimicrobial activity studies of L and the two complexes standards strains of bacteria (Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Bacillus cereus, Enterococcus faecalis, Streptococcus pneumoniae, Listeria monocytogenes, Escherichia coli, Salmonella typhi and Candida albicans) and 22 clinically isolated microorganisms, including multidrug resistant pathogenic microorganisms, were carried out. The free thiosemicarbazone L showed a significant inhibition of the growth all of Gram-positive bacteria tested.

Metal complexes of novel Schiff base derived from the condensation of 2‐quinoline carboxaldehyde and ambroxol drug with some transition metal ions

“…This makes them suitable for penetration into cells and tissues. The polarity of the metal ion will be decreased to a greater extent because of the overlap of the ligand orbital upon complexation, and partial sharing of the positive charge of the metal ion with donor groups . Chelation enhances the delocalization of π‐electrons over the whole chelating ring and induces the penetration of complexes into lipid membranes.…”

Synthesis, characterization, crystal structure of novel Cu (II), Co (III), Fe (III) and Cr (III) complexes with 2‐hydroxybenzaldehyde‐4‐allyl‐S‐methylisothiosemicarbazone: Antimicrobial, antioxidant and in vitro antiproliferative activity

“…The alkylation of sulfur atom is proved by the comparative analysis of 2-hydroxybenzaldehyde-4-allylthiosemicarbazone and 4allyl-S-methylisothiosemicarbazone NMR spectra ( Figure S2). [38] This indicates the presence of tautomeric forms of isothiosemicarbazone in solution. Also peaks of carbon atoms in the methyl group appear in the range 13-30 ppm that are not found in the spectra of corresponding thiosemicarbazone.…”

“…[11,37,38] 4-Allyl-3-thiosemicarbazide (1.31 g, 10 mmol) was dissolved in 20 ml of ethanol with constant stirring. [11,37,38] 4-Allyl-3-thiosemicarbazide (1.31 g, 10 mmol) was dissolved in 20 ml of ethanol with constant stirring.…”

Novel 2‐formylpyridine 4‐allyl‐S‐methylisothiosemicarbazone and Zn(II), Cu(II), Ni(II) and Co(III) complexes: Synthesis, characterization, crystal structure, antioxidant, antimicrobial and antiproliferative activity

“…2‐Formylpyridine 4‐allyl‐ S ‐methylisothioseimicarbazone ( HL ) (Scheme ) was obtained similarly to the method described in the literature …”