Electro-oxidation sensing of sumatriptan in aqueous solutions and human blood serum by Zn(II)-MOF modified electrochemical delaminated pencil graphite electrode.

An electrochemical sensory platform is presented for determination of sumatriptan (SUM) in aqueous solutions and human blood serum. A pencil graphite electrode (PGE) was electrochemically delaminated by cyclic voltammetry technique, and then further modified using nanoparticles of a zinc-based metal-organic framework (Zn(II)-MOF). The fabricated Zn(II)-MOF/EDPGE electrode was utilized for sensitive electrochemical detection of SUM via an electro-oxidation reaction. The Zn(II)-MOF was hydrothermally synthesized and characterized by various techniques. The electrochemical delamination of PGE results in a porous substrate, facilitating the effective immobilization of the modifier. The designed sensor benefits from both enhanced surface area and an accelerated electron transfer rate, as evidenced by the chronocoulogram and Nyquist plots. Under optimized conditions, the developed sensor exhibited a linear response for 0.99-9.52 µM SUM solutions. A short response time of 5 s was observed for the fabricated sensor and the detection limit was found to be 0.29 µM. Selectivity of Zn(II)-MOF/EDPGE towards SUM was evaluated by examining the interference effect of codeine, epinephrine, acetaminophen, ascorbic acid, and uric acid, which are commonly found in biological samples. The developed sensor shows excellent performance with recovery values falling within the range of 96.6 to 111% for the analysis of SUM in human blood serum samples.

Theoretical and experimental investigation of anticancer activities of an acyclic and symmetrical compartmental Schiff base ligand and its Co(ii), Cu(ii) and Zn(ii) complexes.

A compartmental Schiff base ligand, 2,2'-((((((2-hydroxypropane-1,3-diyl)bis(oxy))bis(2,1-phenylene))bis(methylene))bis(azanylylidene))bis(methanylylidene))bis(4-bromophenol) (H3LBr) and its complexes with cobalt(ii), copper(ii) and zinc(ii) including, [Co(HLBr)] (1), [Cu2(LBr)(µ-1,3-OAc)]·MeOH (2) and [Zn(HLBr)] (3) were prepared using template synthesis and characterised by elemental analysis, FT-IR and 1H NMR spectroscopies and single-crystal X-ray diffraction. In the structure of complexes 1 and 3 the metal atom has a MN2O2 environment with tetrahedral geometry while complex 2 has a binuclear structure with a MNO4 environment and square planar geometry around the copper atom. The ability of all compounds to interact with the nine biomacromolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS and Top II) are investigated by docking calculations. For examination of the docking results, the in vitro activities of eight compounds against the human leukemia cell line K562 was investigated by evaluation of IC50 values and mode of cell death (apoptosis).

Synthesis, characterization, crystal structure, and biological studies of two new Cd (II) complexes with 4'-(4-chlorophenyl)-2,2' :6',2"-terpyridine (Clphtpy).

Two new Cd(II) complexes, with the ligand 4'-(4-chlorophenyl)-2,2':6',2"-terpyridine (Clphtpy) formulated as: [Cd(Clphtpy)(NO3)2H2O] (1), and [Cd(Clphtpy)(N3)2]2 (2), have been synthesized and characterized by CHN elemental analysis as well as FT-IR, 1H NMR, absorption and emission spectroscopy, thermal analysis and analyzed structurally by X-ray single-crystal diffraction. The single crystal X-ray analysis showed that the coordination number in complex 1 and 2 were seven and six with N3O4 and N6 coordination sphere, respectively. The antibacterial activities of the synthesized complexes were tested against four gram-positive and four gram-negative bacteria. A biological study of the complexes indicated that the complex 1 exhibited very good activity against most of the tested bacteria and its activity was better than gentamicin as a standard antibiotic.

Preparation of a new electrochemical sensor based on iron (III) complexes modified carbon paste electrode for simultaneous determination of mefenamic acid and indomethacin.

A new chemically modified carbon paste electrodes based on Fe (III) schiff base (Fe (III)-SBMCP)-containing graphite pastes were prepared and evaluated as electrochemical sensor for the voltammetric determination of mefenamic acid and indomethacin in aqueous solutions. The measurements were carried out by application of the differential pulse voltammetry (DPV) method in phosphate buffer solution with pH 3.5. Fe (III) loaded in schiff base can increase anodic peak currents by adsorption of mefenamic acid and indomethacin on electrode surface. The prepared electrode shows voltammetric responses with high sensitivity for mefenamic acid and indomethacin in optimal conditions, which makes it very suitable for simultaneous determination of these compounds. The proposed method was successfully applied for determination mefenamic acid and indomethacin in commercial tablet samples.

Synthesis, Crystal Structure and Electrochemical Behavior of Two New Ni-based Complexes: [Ni2(ttpy)2(SCN)4] and [Ni(ttpy)2](CH3OH)2 (2I).

A simple synthetic procedure has been used to prepare two new nickel(II) complexes [Ni2(ttpy)2(SCN)4], (1) and [Ni(ttpy)2](CH3OH)2 (2I), (2) from 4'-p-tolyl-2,2':6',2"-terpyridine (ttpy) ligand, potassium thiocyanate, and potassium iodide in good yields. The single crystal X-ray analyses reveal that the metals in these complexes are sixfold coordinated with M:L ratio of 1:1 and 1:2 for (1) and (2), respectively. In both complexes, the Ni(II) has distorted octahedral geometry including N5S and N6 environments. Versatile interactions in supramolecular level containing coordinative bonding, I•••H, and N•••H hydrogen bonding, π-π stacking play considerable roles in forming crystal packing of (1) and (2). From obtained data it is concluded that differences in coordination abilities, of used counterions, cause the formation of complexes with 1:1 or 1:2 ratio of metal and ligand. Electrochemical behaviors of the both complexes were investigated.

Cobalt hydroxide nanoparticles modified glassy carbon electrode as a biosensor for electrooxidation and determination of some amino acids.

The electrochemical behavior of some amino acids was investigated on cobalt hydroxide nanoparticles modified glassy carbon (CHM-GC) electrode in alkaline solution. The process of oxidation and its kinetics were established by using cyclic voltammetry, chronoamperometry techniques, and steady-state polarization measurements. The results revealed that cobalt hydroxide promotes the rate of oxidation by increasing the peak current, so these bimolecular reactions are oxidized at lower potentials. Cyclic voltammograms and chronoamperometry indicate a catalytic EC' mechanism to be operative with electrogeneration of Co(IV) as the electrochemical process. Also, the process is diffusion controlled and the current-time responses follow Cottrellian behavior. This result was confirmed by steady-state measurements. The rate constants of the catalytic oxidation of amino acids and the electron transfer coefficients are reported.