Synthesis, crystal structure and applications of palladium thiosalicylate complexes

AbstractThree palladium thiosalicylate complexes [Pd(tb)(bipy)]·3H2O (1), [Pd2(tb)2(bipy)2]·(dtdb)2 (2) and [Pd2(tb)2(phen)2]·dtdb·H2O (3) (bipy=bipyridine; phen=phenanthroline) were prepared from the reaction of PdCl2(CH3CN)2 with dithiosalicylic acid (dtdb) which underwent cleavage to form thiobenzoate anion (tb) in DMF/MeOH. Square planar geometries of the complexes with a N2SO coordination type were proposed on the basis of single crystal X-ray structural study. The presence of trapped and uncoordinated dtdb was observed in complexes 2 and 3. Complexes 1–3 were evaluated as catalysts for Heck coupling reactions of methyl acrylate with iodobenzene, and showed moderate activities at a very low catalyst loading. Complex 1 was found to inhibit the growth of bacteria and scavenge free radicals efficiently

Biological screening and docking studies of unique hybrids synthesized by conventional versus microwave assisted techniques

Purpose: To carry out the synthesis of various hybrids of 1,2,4-triazole in search of potential therapeutic enzyme inhibitory agents, and carry out docking and bovine serum albumin (BSA) binding studies on docking and bovine serum albumin (BSA) binding studies on the hybrids. Methods: The target compounds were synthesized by following a multistep protocol. Compound 1 was synthesized from 4-methoxybenzenesulfonyl chloride (a) and ethyl isonipecotate (b). Compound 1 was refluxed with hydrazine to synthesize compound 2, which was converted to compound 3 through two consecutive steps. Compound 4 and different amines (5a-5i), were utilized to synthesize an array of electrophiles (6a-6i). A series of 1,2,4-triazole hybrids (7a-7i) were synthesized at room temperature by stirring together 3 and 6a-6i. The final structures of 7a-7i were elucidated through 1H-NMR, 13C-NMR and EI-MS spectroscopy. The BSA binding studies were performed by fluorometric titration. Furthermore, antioxidant and enzyme inhibition activities were determined colorimetrically. Results: Compound 7d was the most active antioxidant agent, compared to butylated hydroxyanisole (BHA), while compounds 7d, 7e, 7f, 7g and 7i proved to be potent urease inhibitors with half-maximal inhibitory concentration (IC50) values of 19.5 ± 0.12, 21.1 ± 0.68, 18.2 ± 0.78, 19.9 ± 0.77 and 17.9 ± 0.10 µM, respectively, compared to thiourea with an IC50 of 24.3 ± 0.24 µM. Compounds 7a, 7b, 7d, and 7e exhibited high butyrylcholinesterase inhibition potential, compared to eserine. Conclusion: The synthesized compounds require studies further as potential therapeutic enzyme inhibitory agents in view of their urease inhibition as well as antioxidant activity

Slow diffusion in situ ruthenium/ligand reaction: crystal structures, fluorescence and biological properties

Promoted by RuCl3·3H2O coordination in the mixed solvent DMF/H2O, diverse in situ S–S bond reactions such as S–S bond scission and S-oxidation occurred in the disulfide ligand of 2,2?-dithiodibenzoic acid (dtdb) to yield the new sulfinato-benzoate ligand (sb). The X-ray analysis of complexes of [Ru(phen)2(sb)] (1) and [Ru(bipy)2(sb)·H2O] (2) revealed that in both complexes, the ruthenium ion was found to be in an octahedral geometry, coordinating to the sulfur atom, rather than the oxygen of sulfinate. The complexes were found to be active against the bacterial strains tested with MIC ranging from 14.3–261 ?M. In addition, the metal complexes present strong DNA binding affinity constants in the major or minor grooves at the order of magnitude 105-106 M? 1. The antioxidant activities of the ligand and its metal complexes were investigated through scavenging effects for DPPH in vitro, indicating that the compounds show stronger activities than some standard antioxidants, such as ascorbic and vitamin C

Synthesis, crystal structure and applications of palladium thiosalicylate complexes

Three palladium thiosalicylate complexes [Pd(tb)(bipy)]·3H2O (1), [Pd2(tb)2(bipy)2]·(dtdb)2 (2) and [Pd2(tb)2(phen)2]·dtdb·H2O (3) (bipy = bipyridine; phen = phenanthroline) were prepared from the reaction of PdCl2(CH3CN)2 with dithiosalicylic acid (dtdb) which underwent cleavage to form thiobenzoate anion (tb) in DMF/MeOH. Square planar geometries of the complexes with a N2SO coordination type were proposed on the basis of single crystal X-ray structural study. The presence of trapped and uncoordinated dtdb was observed in complexes 2 and 3. Complexes 1–3 were evaluated as catalysts for Heck coupling reactions of methyl acrylate with iodobenzene, and showed moderate activities at a very low catalyst loading. Complex 1 was found to inhibit the growth of bacteria and scavenge free radicals efficiently