Structure, aggregation and spectroscopic properties of self-assembled Zn(II) Schiff base complexes

Al-Rasbi, Nawal K.; Adams, Harry; Al-Shabibi, Ibtisam; AlAmri, Fatma

doi:10.1016/j.jphotochem.2014.03.020

Cited by 9 publications

(5 citation statements)

References 26 publications

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“…Complexation of H 2 L 1 with Ln(III) ions results in the formation of a new broad band at ∼360 nm (ɛ ∼8,000 M –1 cm –1 ) associated with deprotonation ion of the phenol ring and coordination to an electropositive metal ion which stabilises the lowest energy π–π* excited state. Such behaviour has been seen previously with naphthol based Schiff base ligands …”

Section: Resultssupporting

confidence: 83%

Synthesis, structure and tuneable white-light emission of dinuclear Eu(III),Tb(III)-mixed Schiff base complexes

et al. 2016

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A new family of lanthanide-Schiff base complexes have been synthesized and fully characterized from the novel Schiff base ligand: H 2 L 1 (acetic acid 2-hydroxy-benzylidene-hydrazide). The single crystal X-ray structure and mass spectroscopy reveal the isostructural dinuclear complexes: [Ln 2 L 1 (HL 1 ) 3 (NO 3 )] where Ln = Sm, Eu, Gd and Tb. Upon excitation of the Ln III complexes in solution, their luminescence spectra display the broad ligand centred (LC) band at~470 nm as well as the narrow f-f transitions. In Eu III complex, the LC emission is efficiently quenched, because of the better triplet state energy match to the Eu III -5 D 4 excited states. Doping methods of Eu III with Tb III into the complexes: [Eu x Tb 1-x (L 1 )(HL 1 ) 3 (NO 3 )], x = 0.5 (A), 1.0 (B) and 1.5 (C); in MeOH/DCM (1:10), have revealed variable colours. By careful control of the amounts of Eu III and Tb III in the dinuclear mixed EuTb-complexes, white-light emission is obtained from blue LC band, green Tb III luminescence and red Eu III luminescence. Such behaviour is attributed to the efficient sensitization of Eu III by the ligand and the metal to metal energy transfer from Tb III to Eu III excited 4f states.

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Section: Resultssupporting

confidence: 83%

Synthesis, structure and tuneable white-light emission of dinuclear Eu(III),Tb(III)-mixed Schiff base complexes

et al. 2016

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“…Zn(II) is coordinated with N amino and N carbinitrile atoms with bond lengths Zn‐N9, Zn‐N48,Zn‐N2 and Zn‐N50 are 2.059, 2.058, 1.873 and 1.871 Å . The bond lengths between Zn(II) and oxygen atoms of water molecules are 1.918 and 1.920 Å for Zn‐O72 and Zn‐O69 . Also the angles around the central Zn(II) with surrounding oxygen and nitrogen atoms vary from 73.67° to 163.67°; these values agree with these expected for a distorted octahedron.…”

Section: Computational Detailsmentioning

confidence: 99%

Spectroscopic, DFT and antimicrobial activity of Zn(II), Zr(IV), Ce(IV) and U(VI) complexes of N,N‐ chelated 4,6‐bis (4‐chlorophenyl)‐2‐amino‐1,2‐dihydropyridine‐3‐carbinitrile

Sadeek

El‐Hamid

Zordok

2018

Applied Organom Chemis

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Four novel metal complexes of 4,6‐bis (4‐chlorophenyl)‐2‐amino‐1,2‐dihydropyridine‐3‐carbinitrile (H2L) with Zn(II), Zr(IV), Ce(IV) and U(VI) were synthesized. The structure was elucidated using elemental analysis, melting point, molar conductivity; spectroscopic techniques (IR, 1H NMR, UV–Vis., mass spectra) as well as thermo gravimetric analysis. The spectroscopic data proved that H2L chelated with the metal ions as a bidentate ligand through Namino and Ncarbinitrile atoms. The molecular structure of the complexes was determined using density functional theory (DFT). The central metal ion in each complex is six‐coordinate and the angles around it vary from 62.74° to 166.46°; these values agree with distorted octahedral geometry. The calculated total energy of the complexes found in the region – 406.342 to −459.717 au and the dipole moment change from 4.675 to 13.171D. The antibacterial and antifungal activities of the ligand, metal salts and complexes were estimated on some microorganisms. The complexes showed significant antibacterial profile in comparison to the free ligand.

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“…There has been a considerable increase in the use of metal chelates for cancer treatment after the accidental discovery of the biological activity of platinum complex cisplatin in 1965 by Rosenburg . The organic molecules are designed to combine biological functional groups with a suitable metal ion to mimic active sites of metalloproteins .…”

Section: Introductionmentioning

confidence: 99%

Fabrication, spectroscopic characterization, calf thymus DNA binding investigation, antioxidant and anticancer activities of some antibiotic azomethine Cu(II), Pd(II), Zn(II) and Cr(III) complexes

Abu‐Dief

El-Sagher

Shehata

2019

Applied Organom Chemis

123

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This study was conducted to prepare novel azomethine chelates of Cu(II), Pd(II), Zn(II) and Cr(III) with tridentate dianionic azomethine OVAP ligand 2-[(2-hydroxyphenylimino)methyl]-6-methoxyphenol. The prepared compounds were characterized using elemental analyses and spectral, conductivity, magnetic and thermal measurements. The spectroscopic data suggest that the parent azomethine ligand binds to the investigated metal ions through both deprotonated phenol oxygen and azomethine nitrogen atoms, and adopts distorted octahedral geometry in the case of Cr(III) and Cu(II) ions while tetrahedral and square planar geometries for Zn(II) and Pd(II) ions, respectively. In order to confirm the molecular geometry of the investigated azomethine chelator and its complexes, theoretical density functional theory calculations were employed. Correlation between experimental observations and theoretical calculations of geometry optimization results are in a good agreement. Absorption titration was used to explore the interaction of the investigated azomethine metal chelates with calf thymus DNA, and the binding constant as well as Gibbs free energy were evaluated. Viscosity measurements and gel electrophoresis studies suggest intercalative and replacement binding modes of the azomethine metal chelates with calf thymus DNA. Additionally, the antimicrobial activity of the complexes was screened against some pathogenic bacteria and fungi. This biological study shows that the complexes exhibit a marked inhibitory effect compared to the corresponding ligand and standard drugs.Furthermore, the effect of the novel compounds as antioxidants was determined by reduction of 1,1-diphenyl-2-picrylhydrazyl and compared with that of vitamin C. Finally, in vitro cell proliferation via MTT assay was investigated against colon carcinoma cells (HCT-116), hepatic cellular carcinoma cells (HepG-2(and breast carcinoma cells (MCF-7) to calculate the cytotoxicity of the prepared compounds. Cell proliferation is inhibited for all compounds and in a dose-dependent manner in the sequence of OVAPPd > OVAPCu > OVAPZn > OVAPCr > OVAP azomethine ligand.

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Structure, aggregation and spectroscopic properties of self-assembled Zn(II) Schiff base complexes

Cited by 9 publications

References 26 publications

Synthesis, structure and tuneable white-light emission of dinuclear Eu(III),Tb(III)-mixed Schiff base complexes

Synthesis, structure and tuneable white-light emission of dinuclear Eu(III),Tb(III)-mixed Schiff base complexes

Spectroscopic, DFT and antimicrobial activity of Zn(II), Zr(IV), Ce(IV) and U(VI) complexes of N,N‐ chelated 4,6‐bis (4‐chlorophenyl)‐2‐amino‐1,2‐dihydropyridine‐3‐carbinitrile

Fabrication, spectroscopic characterization, calf thymus DNA binding investigation, antioxidant and anticancer activities of some antibiotic azomethine Cu(II), Pd(II), Zn(II) and Cr(III) complexes

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