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Two water-soluble zinc(II) complexes of b-cyclodextrin-based Schiff bases, viz., mono-6-deoxy-6-(4-(5-chloro-2-hydroxybenzylideneamino)-3,4-diaminotolune)-β-cyclodextrin (4a) and mono-6-deoxy-6-(4-(5-nitro-2-hydroxybenzylideneamino)-3,4-diaminotolune)-β-cyclodextrin (4b) have been synthesized and characterized by different analytical and spectroscopic techniques. These Zn(II) complexes were analyzed for their possible activity against oxidative stress through various biochemical methods. A detailed antioxidant profile directly associated with inflammation related carcinogenesis and several oxidative stress related disorders have been prepared with a motive to evaluate the free radical scavenging activities of the synthesized complexes. The immune cell cytotoxic properties (through MTT assay) and in vitro assay for the evaluation of their antioxidant activities against hydroxyl radical, nitric oxide, singlet oxygen, peroxynitrate and hydrogen peroxide, etc. were investigated. Obtained results clearly demonstrated the role of reactive oxygen species in various phases of oxidative stress related diseases; thus, the antioxidant and free radical scavenging capacities of the two synthesized Zn(II) complexes seem to stand in support of their beneficial effects and novelty for the immune system. [ABSTRACT FROM AUTHOR]

Molecular assembly has become a promising strategy for designing new polydentate ligands. But very often such ligands and their complexes are sparingly soluble in aqueous phase due to their intrinsic hydrophobic character. Pd(II) complexes are good homogeneous catalysts but their poor solubility in aqueous phase may limit their catalytic efficacy in the universal green solvent water. However, solubility related challenges especially in aqueous phase can be mitigated through the formation of inclusion complexes by exploiting the hydrophobic nature of the β-cyclodextrin (β-CD) cavity. Hence, an ionic liquid ChCD (1) was synthesized from β-CD and Choline bromide (ChBr). Next a supramolecular N, N′, O-tridentate ligand 1⊂2 (3) was synthesized by the inclusion of 2,6-diaminopyridine (2) in the hydrophobic β-CD cavity of the ionic liquid ChCD (1) and was well characterized by elemental analysis, UV-visible, FTIR, 1H NMR spectroscopy, etc. The stoichiometry of the inclusion complex 1⊂2 (3) was found to be 1:1 based on UV-visible spectrophotometric study. A new air stable, highly water soluble Pd2+-complex [κ3-N, N′, O-Pd(1⊂2)H2O]OAc (4) was then synthesized from the supramolecular ligand (3) with 1:1 stoichiometry and used as a catalyst for Suzuki cross-coupling reactions in water at ambient temperature with good to excellent yields. The catalyst can be removed and recycled. Additionally, the use of non-toxic solvent water makes the methodology green, sustainable, and economically viable. [ABSTRACT FROM AUTHOR]

An N3O Schiff base (L), 1 : 1 condensate of benzil monohydrazone and 4-pyridine carboxaldehyde, and its Zn(II), Cd(II), and Ag(I) complexes were synthesized and characterized by elemental analyses and various spectroscopic techniques. The crystal structures of [ZnL2Br2] (1), [CdL2I2]·CH2Cl2, (2)·CH2Cl2, and [Ag(L)2]ClO4(3) have been determined using X-ray crystallography. The Zn(II) and Cd(II) complexes show a tetrahedral configuration whereas in the asymmetric unit of3, two independent coordination units of Ag(I) are present. Carbonyl–silver interaction, weak C–H⋯O interaction, and also π–π interaction are present in3in the solid state. The synthesized complexes have antibacterial activity againstKlebsiella pneumoniae 114,Escherichia coli K88,Salmonella typhi ATCC 34,Bacillus subtilis UC564,andStaphylococcus aureus ATCC25923. The results showed that in some cases the antibacterial activities of the complexes were comparable to standard antibiotics Tetracycline and Streptomycin. The antifungal activities of the complexes were also studied forAspergillus niger,Aspergillus oryzae,Penicillium notatum,andSaccharomyces cerevisiae. MIC values of1,2·CH2Cl2, and3are less than the Nystatin standard. A Zn(II), Cd(II) and Ag(I) mononuclear complexes of an N3O Schiff base have been synthesized. The crystal structures of these complexes have been determined. The complexes have antibacterial activity against the bacteriaK. pneumoniae 114,E. coli K88,S. typhi ATCC 34,B. subtilis UC564,andS. aureus ATCC25923and antifungal activity againstA. niger,A. oryzae,P. notatum,andS. cerevisiae. [ABSTRACT FROM AUTHOR]

A new Schiff base ligand, H2L, and its Zn(II) complex were prepared and characterized by different analytical and spectroscopic techniques. The elemental analysis results suggest the stoichiometry of the complex to be 1:1. The molar conductance study shows the non-electrolytic nature of the complex. Infrared spectra reveal that the metal ion is coordinated in tetradentate fashion which was further confirmed by NMR study. The synthesized complex was found to interact with CT-DNA quite efficiently. The DNA binding study of the complex was explored by UV-vis and viscosity measurement. Fluorescence titration studies and the experimental results suggest that the complex might bind to DNA via an intercalative mode. The in silico target prediction and molecular docking experiments confirm that, apart from high interaction potentiality with nucleotides, the complex has possible implications in carcinogenesis, too. [ABSTRACT FROM AUTHOR]