A Trinuclear Zinc–Schiff Base Complex: Biocatalytic Activity and Cytotoxicity

Abstract

A novel trinuclear zinc(II) complex [Zn3L2(μ‐O2CCH3)2(CH3OH)4] (1) that contains an N,O‐donor Schiff base ligand {H2L = 2‐[(2‐hydroxyphenylimino)methyl]‐6‐methoxyphenol} has been synthesized and crystallographically characterized. The X‐ray crystal structure of 1 contains three zinc(II) centers, which have distorted‐octahedral coordination geometry, and the molecule crystallizes in the Pbcn space group. The zinc(II) complex displays significant catecholase oxidation activity in methanolic medium through a ligand‐centered radical pathway. This is the first example of catecholase oxidation through a trinuclear zinc(II)–Schiff base complex by means of the formation of a mononuclear intermediate as [ZnL(dtbc)] (dtbc = 3,5‐di‐tert‐butylcatechol). The fluorescence property of 1 indicates that it can serve as a potential photoactive material. It effectively cleaves the double strand of pBR 322 plasmid DNA at a given concentration (25 μM). The complex shows remarkable cytotoxicity against a human hepatocarcinoma cell line (HepG2).

Topological insights in polynuclear Ni/Na coordination clusters derived from a schiff base ligand

“…The aim to use Na 2-CO 3 as the base to introduce carbonate bridges to the system results in the presence of one Na I in both CCs, while both compounds have different structures to the previously reported homometallic Ni II CC with H 2 L1 [69]. In 1, the use of Na 2 CO 3 did not result in the introduction of carbonate bridging groups; however, in 2, where the reaction solution was exposed to a high CO 2 atmosphere during slow evaporation, a single CO 3 2-anion is observed.…”

“…Previously, this ligand has been involved in the synthesis of homometallic [68][69][70][71] and heterometallic CCs [72][73][74][75]. We recently employed this ligand in 3d/4f chemistry to synthesise a family of homogeneous efficient catalysts towards a domino reaction [76].…”

Antibacterial activity of transition metal complexes with a tridentate NNO amoxicillin derived Schiff base. Synthesis and characterization

“…The UV−Vis spectral data of ( 3 ) as well as ( 4 )−( 8 ) were obtained in DMSO solutions and they showed two bands at 310 and 340 nm. The former band is assigned to the absorption of ( 1 L b → 1 A 1 ) of the benzene ring and remain almost unchanged in the spectra of complexes, while the second band assigned to n–π* (C=N−) transition of the imine group, is shifted to lower wavelength on coordination, suggesting that imine−N is involved in coordination …”

“…The complex ( 4 ) showed a very weak absorption at 430 nm probably due to the coincidence of charge transfer, d →π* and intraligand n →π* transitions. The visible region spectrum of the complex ( 5 ) exhibited two bands at 410 and 470 nm, (e max < 150 M −1 cm −1 ), attributed to metal−ligand charge and 4 T 1g (F) → 4 A 2g (F) (ν 2 ) transition respectively, suggesting octahedral stereochemistry around the cobalt(II) ion …”

Metal Complexes of a Novel Schiff Base Based on Penicillin: Characterization, Molecular Modeling, and Antibacterial Activity Study

“…The electronic absorption spectrum of ligand (HL) displays high energy bands in the ultraviolet region at 206 and 262 nm, corresponds to π → π ∗ transitions of the aromatic and pyridinium ring, and, at 356 nm, corresponds to n → π ∗ intraligand charge transfer band with the involvement of C=N group [31]. However, the additional bands in the higher wavelength region are observed in the complexes which signify metal ligand coordination.…”