Esin İspir

Chemical fixation of CO2 into cyclic carbonates by azo-containing Schiff base metal complexes

Two new ligands containing a –NN– group, 4-((E)-(4-bromophenyl)diazenyl)-2-((E)-(phenylimino)methyl)phenol (L1H, 2), 4-((E)-(4-bromophenyl)diazenyl)-2-((E)-((4-ethylphenyl)imino)methyl)phenol (L2H, 3) and their metal complexes were synthesized. The synthesized metal complexes were used as catalysts for the chemical fixation of CO2 into cyclic carbonates using epoxides which were used as both substrate and solvent. According to analytical, UV-visible and IR data, the metal complexes are formed by coordination of the N and O atoms of the ligands and the metal : ligand ratio was found to be 1 : 2 for all the complexes. The TG and DTA results showed that these complexes had good thermal stability. The molecular structures of ligand 2 (L1H) and its ZnII complex 4 (Zn(L1)2) were determined by single crystal X-ray diffraction studies. After choosing the most active catalyst (Zn(L1)2, 4), optimization studies were performed by changing various parameters. Ionic liquids have been found to have a positive effect and showed the most active performance with (bmim)PF6 + Zn(L1)2 (4) as a binary catalytic system.

The d10 Metal Chelates Derived from Schiff Base Ligands Having Silane: Synthesis, Characterization, and Antimicrobial Studies of Cadmium(II) and Zinc(II) Complexes

The new Zn(II) and Cd(II) complexes were synthesized with the bidentate Schiff base ligands containing the silane group 4‐{[(3‐trimethoxysilanepropyl)imino]methyl}benzene‐2,4‐diol (L1H) and 4‐{[(3‐triethoxysilanepropyl)imino]methyl}benzene‐2,4‐diol (L2H), which were prepared by the reaction of 2,4‐dihydroxybenzaldehyde with 3‐aminopropyltrimethoxysilane and 3‐aminopropyltriethoxysilane respectively. The syntheses of ZnII and CdII chelates of these Schiff bases have been done by the precipitation technique. The synthesized metal complexes were further characterized by elemental analysis, molar conductance measurements, infrared spectra, and UV‐visible spectral data. Based on these characterizations, the metal complexes of ZnII and CdII may be formulated as [M(LI)2] or [M(L2)2] where M ˭ Zn, Cd. The ZnII and CdII metal complexes are formed by the coordination of N, O atoms of the ligands. The Molar conductance values of the ZnII and CdII complexes of the bidentate Schiff base ligands indicate their non‐ionic character. The antimicrobial properties of ZnII and CdII complexes against Klebsiella pneumoniae, Micrococcus luteus, Enterobacter cloacae, Bacillus megaterium, and Mycobacterium smegmatis and two fungi, namely Kluyveromyces marxianus and Rhodotorula rubra are reported. (1) [Cd(L1)2] and (2) [Zn(L2)2] metal chelates exhibited high activity against the Rhodotorula rubra.

Antiproliferative, antioxidant, computational and electrochemical studies of new azo-containing Schiff base ruthenium(II) complexes

A new series of ruthenium(II) complexes 7–11 containing the –NN– group are synthesized and characterized via elemental analysis, and IR, UV-visible and 1H–13C NMR spectroscopy. The solid-state structures of 2, 6 and 9 are determined by single crystal X-ray diffraction studies. The antiproliferative activities of the Schiff base ligands and their ruthenium(II) complexes are investigated in vitro against non-small cell lung cancer cells (H2126), prostate adenocarcinoma cells (PC3) and breast cancer cells (MCF7). The cell proliferation tests are performed as dose-dependent assays at eight concentrations, and 5-fluorouracil is used as the positive control. Compounds 4 and 5 show higher antiproliferative activities against PC3 cells than the other synthesized compounds. Furthermore, the antioxidant capacities of the Schiff base ligands and their ruthenium(II) complexes are investigated in vitro via ferric reduction power, DPPH free radical, and ABTS cation radical scavenging activity tests. The radical scavenging activities of complexes 7–11 are found to be higher than BHT, BHA, and Trolox, which are used as positive controls. The antioxidant activity of the complexes is found to be 30–150 fold higher than the ligands. According to obtained results, the ruthenium complexes in this study may be used as antioxidant agents in the food, drug and cosmetic industries.

Correction: Chemical fixation of CO2 into cyclic carbonates by azo-containing Schiff base metal complexes

Correction for ‘Chemical fixation of CO2 into cyclic carbonates by azo-containing Schiff base metal complexes’ by Mesut Ikiz et al., New J. Chem., 2015, DOI: 10.1039/c5nj00571j.