Zinc Poly Research Articles

A novel layered organic polymer-inorganic hybrid zinc poly (styrene-phenylvinylphosphonate)-phosphate immobilized chiral salen Mn(III) catalyst large-scale asymmetric epoxidation of unfunctionalized olefins

A novel layered organic polymer-inorganic hybrid zinc poly (styrene-phenylvinylphosphonate)-phosphate (ZnPS-PVPA) has been synthesized under mild conditions and diphenol-modified ZnPS-PVPA was used to successfully immobilize the chiral salen Mn(III) by axial coordination. The obtained heterogeneous chiral catalysts exhibited excellent activities and enantioselectivities using sodium periodate as an oxidant for asymmetric epoxidation of unfunctionalized olefins, especially for the epoxidation of α-methylstyrene (conversion: up to 97%; ee: exceed 99%). Moreover, these synthesized catalysts were relatively stable and could be expediently separated from the reaction system, and could be recycled at least ten times without obvious loss of activity and enantioselectivity. These novel catalysts could be efficiently used in large-scale reactions with the enantioselectivity being maintained at the same level, which offer a great possibility for application in industry.

Novel layered crystalline zinc poly(styrene-phenylvinyl phosphonate)-phosphate synthesized by a simple route in a THF–water medium

A novel type of organic polymer-inorganic hybrid material layered crystalline zinc poly(styrene-phenylvinyl phosphonate)-phosphate (ZnPSPPP) was prepared by the reaction of styrene-phenylvinyl phosphonic acid copolymer with zinc acetate dihydrate and sodium dihydrogen phosphate. The ZnPSPPP were characterized by FT-IR, diffusion reflection UV-Vis, AAS, N(2) volumetric adsorption, SEM, TEM and TG. Unexpectedly, the layered crystalline ZnPSPPP obtained was not synthesized with traditional methods as other zinc phosphonates, but with the ones for amorphous reactions without addition of any template. It can be deduced that the layered crystalline ZnPSPPP could have potential applications for heterogeneous catalyst supports.

Retracted Article: Synthesis of a novel type of chiral salen Mn(iii) complex immobilized on crystalline zinc poly(styrene-phenylvinylphosphonate)-phosphate (ZnPS-PVPP) as effective catalysts for asymmetric epoxidation of unfunctionalized olefins

The hypothesized structure of ZnPS-PVPP (a) signifies that the two or more neighboring –PO3H2 groups are in same colloidal precipitation; while (b) signifies that the two neighboring –PO3H2 groups are in different colloidal precipitation.

Structure and properties of nanocomposites based on zinc sulfide and poly(vinylidene fluoride)

The structure and properties of nanocomposites based on zinc sulfide and poly(vinylidene fluoride) were studied. The nanocomposite material was prepared by the matrix isolation technique: ZnS nanoparticles are formed by chemical reactions in a poly(vinylidene fluoride) powder of particle size 0.5–1.0 μm.

Toroidal Zinc Poly(Aminoamine)Phthalocyanine Dendron Synthesis

Phthalocyanines are anticipated for use in important functional materials as a next generation photosensitizer for photodynamic therapy of cancer (PDT). Novel toroidal zinc poly (aminoamine) phthalocyanine dendrons possessing low-generation poly (aminoamine) dendron were molecularly designed and synthesized. They have either biological affinity and photo-antenna ability or promotion of PDT efficacy. Novel toroidal zinc poly ( aminoamine) phthalocyanine dendrons were evaluated for their PDT efficacy in uitro by cancer cell culture.

Solid-state (67)zn NMR spectroscopy in bioinorganic chemistry. Spectra of four- and six-coordinate zinc pyrazolylborate complexes obtained by management of proton relaxation rates with a paramagnetic dopant.

Solid-state (67)Zn NMR spectra of model compounds for metalloproteins, such as [H(2)B(3,5-Me(2)pz)(2)](2)Zn (pz denotes pyrazolyl ring), have been obtained using low temperatures (10 K) to enhance the Boltzmann factor in combination with cross polarization (CP) from (1)H to (67)Zn. Attempts to observe spectra of other model compounds, such as [H(2)B(pz)(2)](2)Zn, were hindered by long relaxation times of the protons. To decrease the proton relaxation times, the high-spin six-coordinate complex [HB(3,4,5-Me(3)pz)(3)](2)Fe has been investigated as a dopant. NMR and EPR measurements have shown that this Fe(II) dopant effectively reduces the (1)H spin lattice relaxation time, T(1), of the zinc samples in the temperature range 5-10 K with minimal perturbations of the (1)H spin lattice relaxation time in the rotating frame, T(1)(rho). Using this methodology, we have determined the (67)Zn NMR parameters of four- and six-coordinate zinc(II) poly(pyrazolyl)borate complexes that are useful models for systems of biological importance. The (67)Zn NMR parameters are contrasted to the corresponding changes in the (113)Cd NMR parameters for the analogous compounds. Further, these investigations have demonstrated that a temperature-dependent phase transition occurs in the neighborhood of 185 K for [HB(3,5-Me(2)pz)(3)](2)Zn; the other poly(pyrazolyl)borate complexes we investigated did not show this temperature-dependent behavior. This conclusion is confirmed by a combination of room-temperature high-field (18.8 T) solid-state (67)Zn NMR spectroscopy and low-temperature X-ray methods. The utilization of paramagnetic dopants should enable low-temperature cross polarization experiments to be performed on a wide variety of nuclides that are important in bioinorganic chemistry, for example, (25)Mg, (43)Ca, and (67)Zn.

Study of the interfacial chemistry of chlorinated rubber paint on different substrates after the curing process

The interfacial chemistry of a highly pigmented chlorinated rubber paint applied over aluminium, cold-rolled and stainless steel, copper and zinc metallic substrates and poly(vinyl chloride) (PVC) polymer sheet have been studied using x-ray photoelectron spectroscopy (XPS). The results obtained by XPS were compared with those of bond strength measurements. The XPS analyses reveal significant differences in the failure mode. The chlorinated rubber paint on the PVC polymer sheet displays the highest bond strength value and on the zinc the lowest. Chemical changes, suggesting dehydrochlorination of chlorinated rubber paint in the paint/metal interfacial region, were only observed on the metallic substrates. With the aluminium, stainless steel, copper and zinc substrates, the curing of the chlorinated rubber paint causes the formation of a highly hydrocarbon-enriched interfacial paint surface. In contrast, the chlorinated rubber paint/PVC polymer sheet system shows no change in the interfacial surface composition. © 1998 John Wiley & Sons, Ltd.

Effects of the alloying elements on the plastic properties of zinc poly crystals

Effects of the alloying elements on the plastic properties of zinc poly crystals

Interactions of metal ions with polynucleotides and related compounds. IV. Degradation of polyribonucleotides by zinc and other divalent metal ions.

AbstractPolyadenylic acid is degraded into mononucleotides and low molecular weight oligonucleotides in a 20 hr. period at 64°C. by the action of Mn (II), Co (II), Ni (II), and Cu (II) ions, and in a 2 hr. period by Zn (II) ions. The latter also degrade poly C, poly U, and RNA at approximately the same rate, but poly I is degraded very much more slowly. No such difference in reaction rates can be observed in the alkaline degradation of polynucleotides. The sluggishness of the reaction with poly I is not due to any highly ordered structure of the zinc–poly I complex, but probably to the weakening of the zinc–phosphate bond through simultaneous binding of the zinc to the inosine base. Evidence for such a hypothesis is derived from the inhibition of the zinc degradation of poly A by inosinic acid or poly I. No drastic difference in the nucleotide composition of the undegraded residue can be observed in the degradation of RNA by zinc and by alkali.