Effect Of Central Metal Ions Research Articles

Effect of central metal ion on some pharmacological properties of new Schiff base complexes. Anticancer, antioxidant, kinetic/thermodynamic and computational studies

The biological capacities of Schiff Base complexes such as anti-cancer, anti-microbial and anti-oxidant properties have been widely studied in the scientific community. However, the effect of central metal ion in the occurrence of their biological properties should be paid more attention. With this aim, novel 2-(hydroxyimino)-1-phenylpropylidene)benzohydrazide (HIPB) Schiff base ligand, and C1/palladium(II), C2/platinum(II), and C3/zinc(II) complexes derived from it were synthesized and characterized. Theoretical studies showed that C2 is more reactive and also has a higher pharmacological affinity than C1 and C3. Experimental investigations were done to compare some biological properties of the complexes. The anticancer assay showed that C1-C3 have the ability to inhibit the growth of HCT116 colon cancer cell lines, but C2 shows a relatively better effect than other. Antioxidant studies using •DPPH (2,2-diphenyl-1-picrylhydrazyl) assay presented the following trend: C2 > C1 > C3 > HIPB. Considering the importance of the antioxidant enzyme catalase in removing reactive oxygen species (ROS), the interaction of C1-C3 with Bovine Liver Catalase (BLC) was evaluated. Kinetic studies showed that C1-C3 can inhibit the catalytic performance of BLC by a similar mechanism, i.e. mixed-type inhibition. Among them, C1 was the strongest inhibitor (Activity inhibition% = 82.2). The C1-C3 quenched the BLC fluorescence emission with dynamic quenching mechanism. The binding affinity to BLC was higher for C1 and C2 than C3. The most important forces in the interaction of C1-C3 with BLC were hydrophobic interactions, which was strongly confirmed by molecular docking data. Tracking the structural changes of catalase showed that BLC undergoes structural changes in the presence of C1 more than C2 and C3.

Effect of central metal ions on interaction of Metal Phthalocyanines composites with chemical analytes

Effect of central metal ions on interaction of Metal Phthalocyanines composites with chemical analytes

Photochemical reaction kinetics research over substituted metal phthalocyanine/La0.8Ce0.2NiO3 catalysts during the desulfurization process of dibenzothiophenes

Among many photocatalysts, metal phthalocyanine-sensitized semiconductor material has become a research hotspot as an efficient deep desulfurization catalyst. In this work, three series modified phthalocyanine, under nitro, amino and carboxyl as substituted groups, have been obtained firstly and named MTNPc, MTAPc, and MTcPc (M = Mn (II), Fe (II), Co (II), Ni (II), Cu (II)). The corresponding metal phthalocyanine/La0.8Ce0.2NiO3 composite catalysts have been successfully synthesized by impregnation method. Through the study on the photocatalytic oxidation desulfurization of DBTs under simulated sunlight, it was found the effect of central metal ions on the catalyst activity is related to their valence electron configuration, while the substituted groups are attributed to their own properties. For the further research, the kinetic study has been introduced to restore the actual reaction process, finding it conformed to the quasi-first reactions and the order of desulfurization degree of the catalysts with the same central metal ions and different peripheral substituted groups is MTcPc/La0.8Ce0.2NiO3 > MTNPc/La0.8Ce0.2NiO3 > MTAPc/La0.8Ce0.2NiO3. Besides, the CoTcPc/La0.8Ce0.2NiO3 with the best desulfurization performance shows t1/2 = 74 min and the reused experiment has been done to study their actual use value.

Biomimetic metalloporphyrin oxidase modified carbon nanotubes for highly sensitive and stable quantification of anti-oxidants tert-butylhydroquinone in plant oil

This study constructed a novel biomimetic enzyme electrochemical biosensor based on tetraphenyl metalloporphyrins functionalized multi-walled carbon nanotubes (MWCNTs). The effect of central metal ions on the catalytic activity of tetraphenyl metalloporphyrin biomimetic enzyme was investigated. It was found that the change of central metal ions had a significant effect on the catalytic performance of metalloporphyrin and Zinc(II) tetraphenylporphyrin (ZnTPP) had the most excellent catalytic property. The electrochemical behaviors of tert-butylhydroquinone (TBHQ) on ZnTPP/MWCNTs modified electrode were investigated. It was found that the redox peak current was increased significantly, which was attributed to the redox peak current to the electrocatalytic activity of ZnTPP and the synergistic effect between ZnTPP and MWCNTs. A strong linear relationship was shown in the concentration range of 0.01 to 1000 μM. This electrochemical sensor also had excellent repeatability, storage, and interference resistance. This work provided a simple and sensitive method for the determination of TBHQ.

Fine-Tuning Intermolecular and Intramolecular Interactions to Build the Films of Tris(Phthalocyaninato) Rare Earth Complexes and Their Comparative Performances in Ambipolar Gas Sensing

High-performance ambipolar chemical sensors toward electron-detonating NH3 and electron-accepting NO2 are obtained based on the solution-based films of two ambipolar ( ${p}$ -fluoro)phenoxy substituted tris(phthalocyaninato) rare earth semiconductors with different metal ions, named Gd2 [Pc(OPhF)8]3(1) and Tb2 [Pc(OPhF)8]3(2). Measurements over the films fabricated from 1 and 2 by a simple quasi-Langmuir–Shafer (QLS) method reveal their ambipolar semiconductor nature, with a ${p}$ -type response in NH3 sensing and n-type response in NO2 sensing, associated with not only suitable highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels but also the different electronic induction effects of the analytes. Interestingly, the devices from the QLS film of 2 with a weaker intermolecular $\pi $ – $\pi $ stacking in J-type (edge-to-edge) packing mode display much better sensing properties to both NH3 and NO2, compared to those from QLS film of 1 with a stronger intermolecular $\pi $ – $\pi $ stacking in the H-type (face-to-face) packing mode. This is mainly because of the larger specific surface area from the J-aggregate with the more uniform-sized nanoparticles for the QLS film of 2. In particular, the highly sensitive, stable, and reproducible responses to 1–20-ppm NH3 with a limit of detection of 0.15 ppm only in 1 min are obtained from the QLS film of 2 for the first time. This paper unravels, first, the effect of central metal ions of sandwich triple-deckers on molecular stacking mode, film structure, and gas sensing performances, which would be helpful for designing and preparing high-performance ambipolar gas sensor devices by combining the molecular design and the device fabrication technique.

MOLECULAR STRUCTURE AND VIBRATION SPECTRA OF PIVALIC ACID

The metal carboxylates such as metal pivalates (salts of the pivalic acid (CH3)3CCOOH) attract a great interest as most promising precursors for chemical vapor deposition (CVD) technology. The possibility to use these substances in the CVD technology is specified by their good thermal stability and high volatility. For modeling of chemical reactions with metal pivalates in the gas-phase and the data on molecular structure will be very useful, in particularly information about effect of central metal ion to geometry of pivalic ligands. In the frame of this task the structures of metal pivalate molecules and pivalic acid (H(piv)) in a gas phase should be finding. The aim of present work is theoretical investigation of the geometry and IR-spectrum of H(piv) using density functional theory (DFT) methods. All calculations were performed using the Gaussian 03 program. The optimization of geometry and quadratic force field calculations were carried out using DFT functionals B3LYP, PBE, PBE0 and BP86 with correlation-consistent triple-ζ valence cc-pVTZ basis sets for O, C, and H. Appropriate assignment of vibrational modes was carried out by the potential energy distribution (PED) analysis among internal coordinates using the SHRINK program. According to DFT computations, the H(piv) molecule has an equilibrium structure of Cs symmetry with Гvib=26A'+19A''. The theoretical and experimental IR-spectra are satisfactorily agreed. The comparison of the ten intensities of highest bands in spectra allowed determining linear correlation between peaks position in experimental and modeling IR-spectra. It should be note the complicated composition of vibrational modes.

Effect of central metal ions of analogous metal-organic frameworks on adsorption of organoarsenic compounds from water: plausible mechanism of adsorption and water purification.

The adsorptive removal of organoarsenic compounds such as p-arsanilic acid (ASA) and roxarsone (ROX) from water using metal-organic frameworks (MOFs) has been investigated for the first time. A MOF, iron benzenetricarboxylate (also called MIL-100-Fe) exhibits a much higher adsorption capacity for ASA and ROX than activated carbon, zeolite (HY), goethite, and other MOFs. The adsorption of ASA and ROX over MIL-100-Fe is also much more rapid than that over activated carbon. Moreover, the used MIL-100-Fe can be recycled by simply washing with acidic ethanol. Therefore, it is determined that a MOF such as MIL-100-Fe can be used to remove organoarsenic compounds from contaminated water because of its high adsorption capacity, rapid adsorption, and ready regeneration. Moreover, only one of three analogous MIL-100 species (MIL-100-Fe, rather than MIL-100-Al or MIL-100-Cr) can effectively remove the organoarsenic compounds. This selective and high adsorption over MIL-100-Fe, different from other analogous MIL-100 species, can be explained (through calculations) by the facile desorption of water from MIL-100-Fe as well as the large (absolute value) replacement energy (difference between the adsorption energies of the organoarsenic compounds and water) exhibited by MIL-100-Fe. A plausible adsorption/desorption mechanism is proposed based on the surface charge of the MOFs, FTIR results, calculations, and the reactivation results with respect to the solvents used in the experiments.

Effect of central metal ions of analogous metal-organic frameworks on the adsorptive removal of benzothiophene from a model fuel

Liquid phase adsorption of benzothiophene (BT) has been studied over CuCl2-loaded analogous metal-organic frameworks (MOFs), metal-benzenedicarboxylates (Me-BDCs, Me: Al, Cr and V), to understand the effect of central metal ions on the adsorptive removal of BT from a model fuel. Among the central metal ions (Al3+, Cr3+ and V3+) of the Me-BDCs only V3+ was oxidized by the loaded CuCl2 (or Cu2+) at ambient condition resulting in V4+ and Cu+ species. Different from the CuCl2-loaded Al- and Cr-BDCs, the CuCl2/V-BDC adsorbed BT remarkably well compared to the virgin V-BDCs which suggests a specific favorable interaction (π-complexation) between the obtained Cu+ in the CuCl2/V-BDC and BT.

Self-assembled nanostructures of optically active phthalocyanine derivatives. Effect of central metal ion on the morphology, dimension, and handedness

Four optically active {(2,3,9,10,16,17,23,24-octa[(S)-2-methylbutoxy]} phthalocyanine derivatives with different central metal ions, namely (S)-H2Pc(β-OC5H11)8 (1), (S)-ZnPc(β-OC5H11)8 (2), (S)-CuPc(β-OC5H11)8 (3), and (S)-NiPc(β-OC5H11)8 (4) have been synthesized and their self-assembly behaviors systematically investigated by electronic absorption and circular dichroism (CD) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) techniques, and X-ray photoelectron spectroscopy (XPS). Metal free phthalocyanine together with its zinc and copper congeners self-assembles into right-handed helical arrangements in a stack of phthalocyanine chromophores according to the CD spectroscopic result, while the nickel complex does so into the left-handed helical arrangements. These helical arrangements, acting as elemental primary structures, further pack in a hierarchical fashion into either highly ordered right-handed fibrous nanostructures with average 300 μm length, 4.8 μm width, and 4.4 μm helical pitch for 1 and 300 μm length, 2.4 μm width, and 1.8 μm helical pitch for 2 but left-handed fibrous nanostructures with average 4 μm length, 0.48 μm width, and 0.12 μm helical pitch for 3 and 300 μm length, 2 μm width, and 1.2 μm helical pitch for 4, clearly revealing the effect of central metal ion on the distance and relative orientation of neighboring phthalocyanine chromophores and in turn the supramolecular chirality, morphology, dimension, and handedness of the self-assembled nanostructures. The present result not only represents a unique phenomenon in the self-assembly of phthalocyanine compounds but more importantly denotes the transcription and amplification of molecular chirality to supramolecular helicity with different helical bias during the self-assembly processes without changing the chiral handles attached to the phthalocyanine chromophore.

Real-time detection of DNA cleavage induced by [M(2,2′-dipyridylamine) 2(NO 3) n] x+ (M = Cd, Cu, Ni, Zn, n = 1,2, x = 0,1): Effect of central metal ions

[M(Hdpa) 2(NO 3) n ] x+ (M = Zn II, Cd II, Cu II and Ni II, n = 1,2, and x = 0, 1) complexes were synthesized, and their activity as catalysts for DNA cleavage reactions were investigated using electrophoresis and linear dichroism technique (LD). All four metal complexes effectively cleaved pBR322 super-coiled DNA. The electrophoresis analysis showed that the [Zn(Hdpa) 2(NO 3)] + and [Cd(Hdpa) 2(NO 3) 2] complexes most effectively cleaved the super-coiled DNA, whereas the [Ni(Hdpa) 2(NO 3)] + complex was least effective. The magnitude of LD in the DNA absorption region reflects the flexibility and length of DNA when the conditions for measurement are properly adjusted. The double stranded DNA cleavage increases the flexibility of DNA and reduces the length, reducing the magnitude of LD in DNA absorption region. Utilizing this LD property, the cleavage was detected in real-time by measuring the LD magnitude with respect to time. The decrease in the LD magnitude was described as the sum of two exponentials. The fast component was tentatively assigned to the cleavage of the single strand, reflecting the increase in the flexibility of DNA, and the slow component was assigned to the cut of the double strand which reduced the length of DNA. The average reaction time was the fastest for the Zn II complex and the slowest for the Ni II complex. The reaction time of the Cd II complex was as fast as that of the Zn II complex. Both the Zn II and Cd II belong to group 12, suggesting that [M(Hdpa) 2(NO 3) n ] x+ with central metal ions from group 12 most efficiently cleaved double stranded DNA.

Effect of Central Metal Ion, CoII in the FeII Spin-Crossover Complex in Emulsion Polymerization of Trifluoroethylmethacrylate Using Poly(Vinyl Alcohol)

To apply to magnetic memory device of nanodispersed spin crossover complex, we have studied the magnetic properties of hetero-spin crossover complex of [Fe(Htrz)3x(4-NHtrz)3� 3x](BF4)2nH2O in emulsion polymerization of trifluoroethylmethacrylate using poly (vinyl alcohol) as a protective colloid. Effect of central transition metal ion of Co II ions on the spin crossover complex in the emulsion polymerization was investigated. The experimental results can be explained by theoretical consideration of electron density between highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and Fe-N bond lengths, magnetic parameters, g-factor using density functional theory. This result was thought to have arisen from ligand field theory with a slight distribution of bond-length based on a slight exchange interaction due to a miner Jahn-Teller effect. [doi:10.2320/matertrans.MB200808]