Characterization of hemoglobin immobilized on gamma-zirconium phosphate

The fact that different γ-zirconium phosphate (γ-ZrP) preintercalation method induced varied degree and type of conformational change of the adsorption protein was confirmed by characterization techniques including circular dichroism (CD), fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD) analysis. The results indicated that the association of hemoglobin with γ-ZrP preintercalated using butylamine was correlated with conformational change in the secondary structure of the protein. γ-ZrP which was preintercalated with tetra (n-butylammonium) hydroxide caused the conformational change of Hemoglobin in both the secondary structure and the tertiary structure. X-ray powder diffraction analysis was used to analyze the crystalline structure of the nanocomposites prepared by relamination. The adsorption isotherms of Hemoglobin on different matrices were set up and fitted with Langmuir and Freundlich equations.     

Investigations on the formation of the crystalline phases of zirconium phosphate and its exchange properties

The phases of cristalline zirconium phosphate were precipitated from a premixed solution of the proper components. The phases of interplanar distance 1.04 nm (phase ) and 0.756 nm (phase ), respectively, were obtained, simultaneously or separately, depending on the ionic strength, temperature and pH of the solution and the digestion time. Ion exchange properties of the phases were investigated. The relationship between the phase transformation and ion exchange properties was studied.     

Acidity of crystalline zirconium phosphate

The acid strength distribution has been measured for the crystalline zirconium phosphate thermally treated at various temperatures. There are two types of acids with remarkably different strength of acidity from one another; +4.8 ≥ Ho ≥ + 3.3 and −3.0 ≥Ho ≥−5.6. When the crystalline zirconium phosphate is thermally treated below 400°C, the total amount of acid is close to the ion exchange capacity and the number of POH groups. The amount of the strong acid gradually increases with temperature of thermal treatment up to 400°C. The amount of acid abruptly decreases around 450°C, and it becomes negligible after the thermal treatment above 490°C. An IR spectrum of pyridine adsorbed on crystalline zirconium phosphate indicates that the strong acid site is Brönsted type. TG-DSC curves and X-ray diffraction patterns also have been measured for the crystalline zirconium phosphate thermally treated at various temperatures. The amount of residual zeolitic water gradually decreased with increasing temperature of thermal treatment. The amount of residual POH groups remains constant up to 445°C, and it abruptly decreases around 480°C. From these results, it has been concluded that both the strong and the weak acid sites are the POH groups.     

Chemical states and lattice dynamics of alpha-diimine Fe2+ complexes intercalated into gamma-zirconium phosphate

The alpha-diimine Fe2+ complexes, [Fe(phen)3]2+, [Fe(bpy)3]2+, and [Fe(terpy)2]2+, (phen: 1,10-phenanthroline, bpy: 2,2'-bipyridyl, terpy: alpha,alpha',alpha'-tripyridine) were intercalated into zirconium dihydrogenphosphate phosphate dihydrate (gamma-zirconium phosphate, gamma-ZrP), Zr(PO4)(H2PO4).2H2O. The rate of the intercalation, the molar ratio of Fe to Zr, was found to be 3.82-7.76%. M?ssbauer spectra indicated that one part of [Fe(phen)3]2+ and [Fe(bpy)3]2+ changed from a low-spin Fe2+ to high-spin Fe2+ state on intercalation, but [Fe(terpy)2]2+ did not change in chemical state. The lattice dynamics of the complexes and the intercalation compounds were investigated in terms of the temperature dependence of the area intensity on the M?ssbauer spectra. A linear relationship was established for all the complex salts and the intercalation compounds investigated between the ln[A(T)/A(82)] and absolute temperature, T, where A(T) and A(82) show the intensities of a doublet at T and 82 K of the M?ssbauer spectra, respectively. From the slope of the linear relation, the theta2M values, which were derived based on the Debye approximation of lattice vibration, were evaluated for the complex salts and the intercalation compounds. The Fe2+ complexes showed theta2M values of 1.27 to 2.32 x 10(6), whereas the intercalation compounds showed very similar values to each other, ranging from 2.19 to 2.39 x 10(6), irrespective of different alpha-diimine ligands. The results were explained in terms of the characteristic layered structure of zirconium phosphate, and by the tight bond between the alpha-diimine Fe2+ complexes and the host gamma-ZrP.     

Thermodynamic properties of crystalline magnesium zirconium phosphate

Heat capacity $ C_{\text{p}}^{^\circ } $ (T) of crystalline magnesium zirconium phosphate was measured between 6 and 815 K. The experimental data obtained were used to calculate the standard thermodynamic functions $ C_{\text{p}}^{^\circ } $ (T), H°(T) ? H°(0), S°(T), G°(T) ? H°(0) over the temperature ranging from T → 0 to 810 K and standard entropy of formation at 298.15 K. The fractal dimension of Mg_0.5Zr₂(PO₄)₃ was calculated from experimental data on the low-temperature (6 ≤ T/K ≤ 50) heat capacity, and the topology of the phosphate’s structure was estimated. Thermodynamic properties of structurally related phosphates M_0.5Zr₂(PO₄)₃ (M = Mg, Ca, Sr, Ba, Ni) were compared.     

Investigations on monotropic liquid crystalline polyurethanes based on biphenylol

2,2′-Azobis-[2-cyano-(4-ethylphenol)] (ABCP) was prepared from parahydroxyacetophenone, using hydrazine sulfate and sodium cyanide. Biphenylol ester of ABCP, 2,2′-azobis-[2-p-biphenyloxy-(4-ethylphenol)] (BECP) was synthesized via the acid route. Combined liquid crystalline polyurethanes (CLCPUs) were synthesized from 1,6-diisocyanatohexane (HDI) and BECP in dimethylformamide (DMF) at 110°C under nitrogen atmosphere. The effect of partial replacement of BECP by 4,4′-dihydroxy biphenyl (DHBP) on liquid crystalline (LC) properties was studied. The polymers were characterized by proton and ¹³C NMR, FTIR, and UV spectroscopy. Elemental analysis were done for determining the percentage content of C, H, and N and the molecular weights of the polymers were determined by gel permeation chromatography (GPC). Thermogravimetric investigations (TGA) of the polyurethanes (PUs) were performed to study the decomposition. The LC nature of the PUs was confirmed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Cross-polarized optical microscopy studies demonstrated the existence of two distinct crystalline morphologies, a spherulitic morphology with high mole ratio of DHBP and a thread-like crystalline morphology with that of BECP. All the PUs synthesized showed a LC nature with a wide temperature range. Partial replacement of BECP by DHBP changed the mesomorphic nature, transition temperature, and temperature range of the mesophase. © 1995 John Wiley & Sons, Inc.     

Thermal decomposition of organic derivatives of crystalline zirconium phosphate

Organic derivatives ofγ-zirconium phosphate were investigated. Then- alkanol derivatives lost their crystal and structural water in several steps. The thermal stability of the molecules increased with increasing number of carbon atoms in the alkyl chain. The investigated materials are less stable thanα-zirconium phosphate derivatives.     

Thermal decomposition of organic derivatives of crystalline zirconium phosphate

The diethylene glycol, benzyl alcohol and benzylamine derivatives of- and-zirconium phosphates were prepared and their thermal behaviour was investigated by means of differential thermal analysis. In all cases, the derivatives of-zirconium phosphate were more stable than those of-zirconium phosphate.

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Zusammenfassung Es wurden Diethylenglykol-, Benzylalkohol- und Benzylamin-Derivate von- und-Zirkoniumphosphaten hergestellt und ihr Thermisches Verhalten mittels DTA untersucht. In allen Fällen waren die Derivate der-Zirkoniumphosphate stabiler als die der-Zirkoniumphosphate.

     

Uptake of pyridine and n-butylamine by crystalline zirconium phosphate

The titration curve of the hydrogen form of crystalline α-zirconium phosphate with pyridine shows only one end point and a phase Zr(C₅H₅NHPO₄)_0·45(HPO₄)_1·55 · H₂O with a basal spacing 10·9 Å is formed. The titration titration curve with a stronger base n-butylamine exhibits two plataux, showing the amine uptake to be a two-step process, and two phases formed through the process are Zr(C₄H₉NH₃PO₄)_1·34(HPO₄)_0·66 · H₂O and Zr(C₄H₉NH₃PO₄)_2·0 · H_2O with basal spacings 18·2 and 18·8 Å, respectively. Sodium ion-exchanged forms of crystalline α-zirconium phosphates also form complexes with pyridine and n-butylamine. The pH values of the amine solutions in this case differ from the case of the hydrogen form of the phosphates. On the basis of the uptake behaviors of pyridine and n-butylamine, two mechanisms of the complex formation of crystalline α-zirconium phosphates with these amines are proposed as follows: (1) Exchange reaction of interlayer cations of crystalline α-zirconium phosphate with pyridinium and n-butylammonium cations; (2) Intercalation reaction of these unionized organic bases into the interlayer spaces.     

Investigations on liquid crystalline partially fluorinated alkyl and succinimidyl benzoates

The synthesis and mesophase properties of partially fluorinated alkoxy‐substituted benzoic alkyl and succinimidyl (NHS) esters with one, two and three perfluoroalkyl alkoxy chains are reported. The mesophases were studied using differential scanning calorimetry (DSC), polarizing optical microscopy and X‐ray diffraction of non‐oriented samples. The SmA phases of the one‐chain methyl esters are monotropic, while those of the one‐chain NHS esters are enantiotropic. The more wedge‐shaped two‐ and three‐chain alkyl esters do not form mesophases, whereas the succinimidyl analogues exhibit hexagonal columnar phases. Their enhanced mesophase stability is caused by the higher polarity of the succinimidyl ring with respect to the alkyl ester groups. Aggregation of the dipolar succinimidyl groups, together with the microsegregation of the lipophilic and fluorophilic segments of the partially fluorinated alkoxy chains, is assumed to lead to a threefold structured morphology in both the SmA and the Col_h phases. This threefold structuring can be regarded as analogous to known morphologies of ABC triblock copolymers.     

Investigations on liquid crystalline partially fluorinated alkyl and succinimidyl benzoates

The synthesis and mesophase properties of partially fluorinated alkoxy-substituted benzoic alkyl and succinimidyl (NHS) esters with one, two and three perfluoroalkyl alkoxy chains are reported. The mesophases were studied using differential scanning calorimetry (DSC), polarizing optical microscopy and X-ray diffraction of non-oriented samples. The SmA phases of the one-chain methyl esters are monotropic, while those of the one-chain NHS esters are enantiotropic. The more wedge-shaped two- and three-chain alkyl esters do not form mesophases, whereas the succinimidyl analogues exhibit hexagonal columnar phases. Their enhanced mesophase stability is caused by the higher polarity of the succinimidyl ring with respect to the alkyl ester groups. Aggregation of the dipolar succinimidyl groups, together with the microsegregation of the lipophilic and fluorophilic segments of the partially fluorinated alkoxy chains, is assumed to lead to a threefold structured morphology in both the SmA and the Col_h phases. This threefold structuring can be regarded as analogous to known morphologies of ABC triblock copolymers.     

Investigations on hopeite- and phosphophyllite-containing phosphate coatings on steel

A series of phosphate coatings on steel produced by different procedures and containing differing contents of hopeite and phosphophyllite, are investigated by SEM, XRD, XRF on removed coatings, AES, ESCA, and EDX microanalysis. The morphology of the coatings is mainly determined by the procedure employed (spray or immersion). The hopeite/phosphophyllite ratio of the layers depends on the phosphating bath composition and is quantitatively determinable with sufficient accuracy by XRD, XRF on the removed phosphate layers, and AES. Further results are that an immersion time of more than 60 s does not considerably increase the layer thicknesses and that the first-grown crystalline layers on the steel sheets are hopeite-enriched.     

Electronic structure of crystalline copper phthalocyanine

The electronic structure of copper-phthalocyanine (CuPc) has been studied both experimentally and theoretically. Experiments have been performed on alpha and beta crystalline phases, using photoemission spectroscopy to probe core levels and valence band spectra. Different photon energies have been used, in order to probe different sample depths. Only minor differences have been observed in the experimental data on the two different phases, except for a small charge effect on the beta phase crystal. First-principles calculations have been performed using the density functional for molecular and three-dimensional periodic solids (Dmol(3)) code on both the single CuPc molecule and the beta phase, allowing the identification of the different atomic and angular contributions to the experimental density of states. In particular, the highest occupied molecular level is mainly due to Cu and N states. The comparison between theoretical data obtained for the CuPc in the beta phase and in the single molecule shows that the interchain interaction between the molecules is negligible, whereas slightly stronger intrachain interactions occur.