Highlighting the Importance of Water Alkalinity Using Phosphate Buffer Diluted With Deionized, Double Distilled and Tap Water, in Lowering Oxidation Effects on Human Hemoglobin Ozonated at High Ozone Concentrations in vitro.

In autohemotherapy, it is important to find a way to lower the effects of oxidation, especially at high concentrations of ozone. One of the parameters, other than ozone concentration, which can have a significant effect on the stability and rate of decomposition of ozone at high concentrations, is the presence of ions in water. A number of spectroscopic techniques including intrinsic fluorescence, circular dichroism and UV-VIS were used as well as SDS-PAGE, Native-PAGE dynamic light scattering and water ion analysis, in order to investigate the effects of two relatively high concentrations of ozone on purified human hemoglobin (Hb) in phosphate buffer and diluted versions with deionized, double distilled and tap water in vitro. Purified human Hb and not whole blood human Hb was used in this study, since the addition of water to the whole blood would have caused the RBCs to lyse, affecting the purification of Hb for further analysis. Therefore, using purified Hb, it was possible to investigate the effects of dilution of 50 mM phosphate buffer to 10 mM phosphate buffer with different water types including non-ion containing deionized and double distilled water as well as ion-containing tap water, when ozonated at 55 and 80 µg/ml ozone. The fundamental changes in the secondary and tertiary structures of Hb were seen to be related to non-ozonated Hb samples diluted with deionized and double distilled waters, respectively. Generally, Hb oligomerization was more likely to occur at the higher concentration of ozone (80 µg/ml) and in samples where phosphate buffer was diluted with non-ion containing deionized and double distilled waters and not the ion-containing tap water. This could be explained by the presence of water alkalinity or bicarbonate ions in tap water, which can scavenge free radicals and reduce Hb oxidation/oligomerization. Therefore, it was concluded that Hb could best withstand high concentrations of ozone in the presence of the undiluted 50 mM phosphate buffer followed by phosphate buffer diluted with tap water, containing bicarbonate ions.

A manganese(iii) Schiff base complex immobilized on silica-coated magnetic nanoparticles showing enhanced electrochemical catalytic performance toward sulfide and alkene oxidation.

In this study, a novel Mn(iii)-Schiff base complex was synthesized and characterized. The structure of this complex was determined to be a deformed octahedral coordination sphere by single-crystal X-ray diffraction analysis. The Mn(iii)-Schiff base complex was supported on silica-coated iron magnetic nanoparticles via axial coordination by one-step complex anchoring to produce a heterogenized nanocatalyst. After this, the complex was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), and powder X-ray diffraction (XRD). Moreover, atomic absorption spectroscopy was used to determine the amount of the loaded metal. The heterogenized nanocatalyst effectively catalyzed the oxidation of a broad range of sulfides and alkenes with H2O2 in the presence of a glassy carbon electrode, applying voltage to the reaction mixture. The results showed that the application of a potential to the reaction mixture could significantly decrease the reaction time when compared with the case of similar chemical oxidation reactions. In addition, an excellent value of turnover frequency (17 750 h-1) was achieved for the electrochemical oxidation of styrene. Moreover, the nanocatalyst showed good recoverability without significant loss of its activity within six successive runs in the electrochemical oxidation of methyl phenyl sulfide and cyclooctene. The electrochemical properties and stability of Fe3O4@SiO2-[MnL(OAc)] were investigated by cyclic voltammetry measurements and chronoamperometry technique.

Novel X-ray sequences and crystal structures of Persian and Starry sturgeon methemoglobins: Highlighting the role of heme pocket waters in causing autoxidation.

Although there is a high sequence similarity between mammalian and fish hemoglobin (Hb), the oxidation and heme loss rates can vary greatly between them such that fish Hbs oxidise much more rapidly than mammalian Hbs. There is to date no sequence or structural data for any sturgeon Hb to reveal the level of autoxidation in these fish. In this study, novel high resolution X-ray sequences and crystal structures of methemoglobin (Met-Hb) from two sturgeon fish including Persian sturgeon (Acipenser percisus) and Starry sturgeon (Acipenser stellatus) belonging to the Caspian sea has been determined. A comprehensive sequence and structure comparison between these sturgeon Met-Hbs and a number of non-sturgeon and normal and sickle cell anaemia human Hb in varying heme states has been carried out highlighting (i) the structural variability in the heme propionate groups; (ii) the existence of certain residues or their displacement and shift in the heme pocket allowing entry of water molecules into the heme pocket; (iii) the importance of the number of water molecules in the heme pocket; (iv) the hydrogen bonding between oxygens of A and D propionate groups and that of waters in the heme pocket; and (v) the role of heme binding waters causing oxidative stress and heme autoxidation.

Molecular insights into the effect of ozone on human hemoglobin in autohemotherapy: Highlighting the importance of the presence of blood antioxidants during ozonation.

Ozone has been known for several decades, with its antiseptic and therapeutic effects determined by the hormesis theory. It is shown that the therapeutic efficacy of ozone therapy may be partly due to the controlled and moderate oxidative stress produced by the reaction of ozone with several biological components. In this study, the effect of ozone on healthy human hemoglobin (Hb) in the whole blood environment (in the presence of antioxidants) and in the purified form (in the absence of antioxidants) is investigated using a number of different techniques including intrinsic fluorescence, circular dichroism and UV-VIS absorption spectroscopy as well as SDS- and Native-PAGE and dynamic light scattering. The results show that the presence of antioxidants prevents damage to Hb while its absence means that as the exposure to ozone is increased, Hb is increasingly damaged. These results highlight the importance for the use of appropriate doses of ozone, for patients with different diseases and hence antioxidant levels, in autohemotherapy.

Zeolite encapsulated Ni(II)-Schiff-base complex: a novel size-selective electro-catalyst for the determination of the purity of stevioside.

Ship-in-a-bottle complex of nickel(II) containing the ligand N,N'-bis(2,4-dihydroxyacetophenone)-2,2-dimethylpropandiimine (H2{salnptn(4-OH)2}) has been synthesized in zeolite Y. The characteristics of the encapsulated complex are identified by the methods of EDX, SEM, XRD, FT-IR and cyclic voltammetry. A catalytic effect in the electrochemical oxidation of glucose, fructose and sucrose, and a blocking effect in stevioside oxidation are demonstrated on the Ni(II){salnptn(4-OH)2}-Y/CPE. The effects of some parameters, such as potential scan rate and concentration of carbohydrates are investigated. The rate constants for the catalytic reaction (k') of carbohydrates are also obtained. The size-selective electro-catalyst shows a good linear dependency on carbohydrates' concentration in the range of 0.01-0.06 M with the detection limit of 6.4mM at the signal-to-noise ratio of 3. Furthermore, the modified electrode exhibits no interference with the simultaneous presence of stevioside. In brief, these results demonstrate that Ni(II){salnptn(4-OH)2}-Y composites have a great potential for synthesizing size-selective electrocatalysts for determining the purity of stevioside.

{µ-2-[(3-Amino-2,2-dimethyl-prop-yl)imino-meth-yl]-6-meth-oxy-phenolato-1:2κ(5)O(1),O(6):N,N',O(1)}{2-[(3-amino-2,2-dimethyl-prop-yl)imino-meth-yl]-6-meth-oxy-phenolato-1κ(3)N,N',O(1)}-µ-azido-1:2κ(2)N:N-azido-2κN-methanol-2κO-dinickel(II).

Two distinct coordination geometries are found in the binuclear title complex, [Ni(2)(C(13)H(19)N(2)O(2))(2)(N(3))(2)(CH(3)OH)], as one Schiff base ligand is penta-dentate, coordinating via the anti-cipated oxide O, imine N and amine N atoms (as for the second, tridentate, ligand) but the oxide O is bridging and coordination also occurs through the meth-oxy O atom. The Ni(II) atoms are linked by a µ(2)-oxide atom and one end of a µ(2)-azide ligand, forming an Ni(2)ON core. The coordination geometry for the Ni(II) atom coordinated by the tridentate ligand is completed by the meth-oxy O atom derived from the penta-dentate ligand, with the resulting N(3)O(3) donor set defining a fac octa-hedron. The second Ni(II) atom has its cis-octa-hedral N(4)O(2) coordination geometry completed by the imine N and amine N atoms of the penta-dentate Schiff base ligand, a terminally coordinated azide N and a methanol O atom. The arrangement is stabilized by an intra-molecular hydrogen bond between the methanol H and the oxide O atom. Linear supra-molecular chains along the a axis are formed in the crystal packing whereby two amine H atoms from different amine atoms hydrogen bond to the terminal N atom of the monodentate azide ligand.

Di-µ-azido-κ(4)N:N-bis-({2-[(3-amino-2,2-dimethyl-prop-yl)imino-meth-yl]-6-meth-oxy-phenolato-1κ(3)N,N',O(1)}copper(II)).

The complete mol-ecule of the title complex, [Cu(2)(C(13)H(19)N(2)O(2))(2)(N(3))(2)], is generated by the application of a centre of inversion. The central Cu(2)N(2) core is a rhombus as the µ(2)-azide ligands bridge in an asymmetric fashion. Each Cu(II) atom is also coordinated by a monoanionic tridentate Schiff base ligand via the anti-cipated oxide O, imine N and amine N atoms. The resulting N(4)O coordination geometry is based on a square pyramid. No specific inter-molecular inter-actions are noted in the crystal packing, but the amine H atoms form intra-molecular N-H⋯O(oxide)/N(azide) hydrogen bonds.

{5,5'-Dimeth-oxy-2,2'-[1,1'-(2,2-dimethyl-propane-1,3-diyldinitrilo)-diethyl-idyne]diphenolato-κO,N,N',O'}copper(II) monohydrate.

The tetra-dentate dianion in the title complex hydrate, [Cu(C(23)H(28)N(2)O(4))]·H(2)O, provides the Cu(II) atom with a cis-N(2)O(2) donor set. There is a significant twist from a regular square-planar geometry with the dihedral angle formed between the two six-membered CuOC(3)N chelate rings being 32.14 (8)°. The water mol-ecule forms hydrogen bonds to each of the coordinating O atoms of a given complex mol-ecule. Supra-molecular layers in the bc plane are formed in the crystal packing through C-H⋯O and C-H⋯π inter-actions.

2-{(1E)-1-[(3-{(E)-[1-(2-Hy-droxy-4-meth-oxy-phen-yl)ethyl-idene]amino}-2,2-di-methyl-prop-yl)imino]-eth-yl}-5-meth-oxy-phenol.

Mol-ecules of the title compound, C(23)H(30)N(2)O(4), are located on a crystallographic mirror plane. The mol-ecule has a curved shape with the dihedral angle formed between the two benzene rings being 55.26 (5)°. Intra-molecular O-H⋯N hydrogen bonds are noted. In the crystal, supra-molecular layers are formed in the ac plane owing to the presence of C-H⋯π inter-actions.

{4,4'-Dibromo-2,2'-[2,2-dimethyl-propane-1,3-diylbis(nitrilo-methanylyl-idene)]diphenolato-κO,N,N',O'}nickel(II).

In the title compound, [Ni(C(19)H(18)Br(2)N(2)O(2))], the Ni(II) ion, lying on a twofold rotation axis, is coordinated by two N atoms and two O atoms from the Schiff base ligand in a distorted square-planar geometry. Weak inter-molecular C-H⋯O hydrogen bonds stabilize the crystal structure.

A UV-vis spectroscopic study of 1:2 adduct formation of some free-base meso-tetraaryl- and meso-tetraalkylporphyrins with PhSnCl3 and (CH3)2SnCl2.

Molecular complexation of meso-tetraalkylporphyrins (with primary alkyl residues) (alkylpor), para-substituted meso-tetraphenylporphyrins (para=H, CH(3), Cl, OCH(3), NO(2)) (arylpor) and meso-teramesitylporphyrin (H(2)tmp) with PhSnCl(3) (A(I)) and (CH(3))(2)SnCl(2) (A(II)) led to the red shift of the Soret bands. Comparison of the Soret bands of A(I) (or A(II))(2)arylpor with those of (A(I) or A(II))(2)alkylpor shows a red shift of ca. 10-20nm for the formers with respect to the latters. According to the very similar saddled porphyrin core reported for the dications of H(2)tpp and H(2)t(n-Pr)p with CF(3)COOH, it may be concluded that in addition to the Q(0,0) bands the Soret bands may be also affected by the pi-donation of meso-aryl substituents to the porphyrin aromatic system. An overlap between one of the e(1g) orbital of phenyl groups and the a(1u) orbital of porphyrin core is suggested to explain the observed red shifts in the case of pi-donor para-substituents. Very similar red shift of the Soret bands of (A(I) or A(II))(2)H(2)t(4-OMe)pp and (A(I) or A(II))(2)H(2)t(4-NO(2))pp with respect to that of (A(I) or A(II))(2)H(2)t(n-Pr)p, in spite of the pi-electron withdrawing effects of para-NO(2) groups, seems to be resulted in by the pi-interaction of LUMOs of (4-NO(2))phenyl substituent with e(g) orbital of porphyrin core; this interaction would lead to the stabilization of e(g) orbital and the observed red shift of the Soret band. However, due to the distribution of electron densities of the a(2u) orbital on meso-positions, as well as the central nitrogens, the Q(0,0) bands are more strongly affected by the pi-donation of meso-aryl groups to the porphyrin core.

A novel wire-type lead-selective electrode based on bis (1'-hydroxy-2'-acetonaphthone)-2,2'-diiminodiethylamine.

The preparation of a lead-selective electrode based on bis(1'-hydroxy-2'-acetonaphthone)-2,2'-diiminodiethylamine (L) as sensing material is reported. The plasticized PVC membrane containing 30% PVC, 67% ortho-nitrophenyloctylether (NPOE) and 3% ionophore L was directly coated on a graphite rod. This electrode exhibits a nearly Nernstian slope of 27.8+/-0.2 mV decade(-1) over a concentration range 10(-6)-10(-2) M with a detection limit of 4.0 x 10(-7) M. The response time of the electrode was found to be <20 s. The potential of the sensor was independent on pH variations in the range 5-7. The selectivity of the electrode towards lead ions over Na+, K+, Ag+, Ca2+, Sr2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, La3+, Sm3+ and Er3+ ions was investigated. The prepared electrode was successfully used as an indicator for titration of a lead solution with a standard solution of EDTA. The applicability of the sensor for Pb2+ measurement in various synthetic and real samples has been also demonstrated.

A coated wire-type lead(II) ion-selective electrode based on a phosphorylated calix[4]arene derivative.

The preparation of a lead-selective electrode based on 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis-(diphenylphosphinoylmethoxy)calix[4]arene (1) as an ionophore is reported. The plasticized PVC membrane containing 30% PVC, 57% ortho-nitrophenyloctylether (NPOE), 4% sodium tetraphenylborate (NaTPB) and 9% ionophore 1 was directly coated on a graphite electrode. It exhibits a nearly Nernstian slope of 28.0 +/- 0.2 mV decade(-1) over a concentration range of 1 x 10(-5) - 1 x 10(-2) mol dm(-3) with a detection limit of 1.4 x 10(-6) mol dm(-3). The response time of the electrode was found to be ca. 17 s. The potential of the sensor was independent of the pH variation in the range 3.5 - 5.0. The selectivity of the electrode performance towards lead ions over Th4+, La3+, Sm3+, Dy3+, Y3+, Ca2+, Sr2+, Cd2+, Mn2+, Zn2+, Ni2+, Co2+, NH4+ Ag+, Li+, Na+ and K+ ions was investigated. The prepared electrode was used successfully as an indicator electrode for a potentiometric titration of a lead solution using a standard solution of EDTA. The applicability of the sensor for Pb2+ measurements in various synthetic water samples spiked with lead nitrate was also checked.