Synthesis and thermal studies of tetraaza macrocylic ligand and its transition metal complexes. DNA binding affinity of copper complex

Synthesis, structural, spectroscopic and electric/dielectric studies of a nanocrystalline Ni(ii) complex based on [(1,3-diphenyl-1H-pyrazol-4-yl)methylene]thiocarbonohydrazide

A Ni2+ nanocomplex based on a heterocyclic ligand containing a pyrazole moiety was developed in this work, and its electric conductivity and dielectric characteristics were studied. The Ni2+ nanocomplex with the general formula [Ni(PyT)2(H2O)2]Cl2·½H2O, where PyT = [(1,3-diphenyl-1H-pyrazol-4-yl)methylene]thiocarbonohydrazide, was characterized using various techniques, including elemental and thermal analyses, as well as conductivity, magnetism, TEM, and spectroscopic (FT-IR, UV-Vis and XRD) studies. The results showed that PyT was bonded to the Ni(ii) centers via a neutral bidentate ligand, resulting in an octahedral-shaped, thermally stable mononuclear complex. The frequency response of the dielectric properties and ac conductivity was studied in the range from 200 Hz to 6 kHz. Both dielectric constant and dielectric loss decreased with increasing frequency. In addition, the effect of temperature was investigated in the range of 294.1-363.4 K. The ac conductivity increased with increasing temperature in the range of 294.1-333.5 K. The ac conduction is described as correlated barrier hopping between non-intimate valence alternation pairs. Furthermore, the PyT and Ni(PyT) nanocomplex structures were optimized using theoretical calculations and DFT computations.

Novel electrospun fibers as carriers for delivering a biocompatible Sm(iii) nanodrug for cancer therapy: fabrication, characterization, cytotoxicity and toxicity

The current study represents the successful fabrication and characterization of a Sm(iii) nano complex based on 2-cyano-N'-((4-oxo-4H-chromen-3-yl)methylene)acetohydrazide (CCMA). The fibrous Sm(iii) nanocomplex has been fabricated by the electrospinning technique. SEM analysis of the electrospun fibers has revealed that the fibers have a uniform structure and smooth surface without observing Sm(iii) nanocomplex crystals, i.e. the Sm(iii) nanocomplex has been well incorporated into the fibers. In vitro antitumor activity against two carcinogenic cell lines (HepG-2 and E.A.C.) as well as in vivo toxicity of pure Sm(iii) nanocomplex and its electrospun fibers have been detected. The biological results have shown that there is a significant antitumor activity with low toxicity of the pure Sm(iii) nanocomplex and its electrospun fibers with respect to different standard antitumor drugs. Also, the electrospun fibers recorded higher cytotoxicity (IC₅₀ = 0.1 μM (Hep-G); 0.09 μM (E.A.C)) and lower toxicity (LD₅₀ = 350 mg kg^-1) than the pure ones. The in vitro release rate of the Sm(iii) nanocomplex from electrospun fibers has also been detected. The results have shown that the burst releasing of the Sm(iii) nanocomplex is about 22% after 1 h at the beginning, then a cumulative release increased gradually over the following hours. All results demonstrate the potential use of the Sm(iii) nanocomplex as a potent antitumor drug and its electrospun fibers as superior drug carriers for the treatment of tumors.

Co(ii), Ni(ii), Cu(ii) and Cd(ii)-thiocarbonohydrazone complexes: spectroscopic, DFT, thermal, and electrical conductivity studies

New and stable coordinated compounds have been isolated in a good yield. The chelates have been prepared by mixing Co(ii), Ni(ii), Cu(ii), and Cd(ii) metal ions with (1E)-1-((6-methyl-4-oxo-4H-chromen-3-yl)methylene)thiocarbonohydrazide (MCMT) in 2 : 1 stoichiometry (MCMT : M²⁺). Various techniques, including elemental microanalyses, molar conductance, thermal studies, FT-IR, ¹H-NMR, UV-Vis, and XRD spectral analyses, magnetic moment measurements, and electrical conductivity, were applied for the structural and spectroscopic elucidation of the coordinating compounds. Further, computational studies using the DFT-B3LYP method were reported for MCMT and its metal complexes. MCMT behaves as a neutral NS bidentate moiety that forms octahedral complexes with general formula [M(MCMT)₂Cl(OH₂)]Cl·XH₂O (M = Cu²⁺; (X = ½), Ni²⁺, Co²⁺; (X = 1)); [Cd(MCMT)₂Cl₂]·½H₂O. There is good confirmation between experimental infrared spectral data and theoretical DFT-B3LYP computational outcomes where MCMT acts as a five-membered chelate bonded to the metal ion through azomethine nitrogen and thiocarbonyl sulphur donors. The thermal analysis is studied to confirm the elucidated structure of the complexes. Also, the kinetic and thermodynamic parameters of the thermal decomposition steps were evaluated. The measured optical band gap values of the prepared compounds exhibited semiconducting nature. AC conductivity and dielectric properties of the ligand and its complexes were examined, which showed that Cu(ii) complex has the highest dielectric constant referring to its high polarization and storage ability.

Structural elucidation, theoretical investigation, biological screening and molecular docking studies of metal(II) complexes of NN donor ligand derived from 4-(2-aminopyridin-3-methylene)aminobenzoic acid

Complexes of 4-(((2-aminopyridin-3-yl)methylene)amino)benzoic acid ligand with cobalt(II) (1), nickel(II) (2), copper(II) (3), zinc(II) (4) and palladium(II) (5) are synthesized and characterized by using different spectroscopic methods like, UV-Visible, infrared, ¹H, ¹³C NMR, molar conductance, ESR and elemental analysis. Quantum chemical computations were made using DFT (density functional theory), B3LYP functional and 6-31+ +G(d,p)/SDD basis set in order to determine optimized structure parameters, frontier molecular orbital parameters and NLO properties. Based on DFT and experimental evidence, the complexes ensured that the octahedral geometry have been proposed for complexes 1, 2 and 4, square planar for complexes 3 and 5. All the complexes showed only residual molar conductance values and hence they were considered as non-electrolytes in DMF. In addition, the anti-proliferative activity of the compounds was evaluated against different human cancer cell lines (IMR-32, MCF-7, COLO205, A549, HeLa and HEK 293) and cisplatin is used as a reference drug. Compounds 1 and 4 showed remarkable cytotoxicity in five cancer cell lines tested except MCF-7. Also, the compounds were examined for their in vitro antimicrobial and scavenging activities. The molecular docking results are well corroborated with the experimental anticancer activity results.

Synthesis, DNA and BSA binding, in vitro anti-proliferative and in vivo anti-angiogenic properties of some cobalt(iii) Schiff base complexes

In the recent times metal complexes with dual mechanisms of action, anti-cancer and anti-angiogenic, have gained substantial interest in the field of medicinal chemistry.

Macrocyclic complexes: synthesis, characterization, antitumor and DNA binding studies

The present paper deals with the synthesis of novel macrocyclic complexes of the type [MLX]X, where [(M = Co(II) (1), and Ni(II) (2) X = (Cl₂)]. The complexes are synthesized by the reaction of ligand(L)diquinolineno[1,3,7,9]tetraazacyclododecine-7,15-ethane(14H,16H)-benzene with the corresponding metal salts. The synthesized complexes are thoroughly characterized by elemental analysis, FT-IR, ¹H-NMR, Mass and electronic spectra. The complexes (1) and (2) were evaluated for in vitro cytotoxicity against human breast adenocarcinoma cell (MCF-7). MTT cytotoxicity studies shows both the complexes are most effective. The binding properties of these complexes with calf thymus-DNA were studied by absorption, emission spectra, viscosity measurements, and thermal denaturation studies. On binding to CT-DNA, the absorption spectrum undergoes bathochromic and hypochromic shifts. The absorption spectral results indicate that the intrinsic binding constant (K_b) are 4.8 × 10⁵ M^-1 for (1) and 3.9 × 10⁵ M^-1 for (2) respectively, suggesting that complex (1) binds more strongly to CT-DNA than complex (2). The viscosity measurement results revealed the viscosity of sonicated rod like DNA fragments increased when the complex was added to the solution of CT-DNA. The synthesized ligand and its metal complexes are screened for antibacterial and antifungal activities.