Monomer sequencing and microstructural analysis on polymers of dimethyl norbornene dicarboxylate and 7‐oxanorbornene dicarboxylic derivatives employing ruthenium catalysts by ring‐opening metathesis polymerization

The physiochemical properties, comonomer sequencing, and regiospecificity of the linkages between monomeric units within homo/copolymers based on 5,6‐di‐substituted norbornene and 7‐oxanorbornene type monomers by ring‐opening metathesis polymerization are reported and correlated to their primary and secondary structural elements. In general, first‐generation Grubbs‐ I1 ruthenium catalyst generates polymers with high trans content that exhibits an extended secondary structure with exo,exo substituents, whereas second‐generation Grubbs‐ I2 catalyst produces polymers with high cis content that forms tight turns, resulting in a compact structure. Furthermore, I2 ‐produced polymers exhibit a high level of alternating cis–trans double bonds along their polymeric backbone. In stark contrast, both first‐ and second‐generation Grubbs catalysts display complete reversal in cis/trans selectivity when an oxygen atom is in position‐7 of the norbornene‐ring along with mono‐endo‐substitution in position‐5 or 6, and hence highlighting the importance of stereoelectronic complexation by the catalyst with the next incoming monomer for cis/trans selectivity. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2477–2501     

Fern constituents: triterpenoids from Adiantum capillus-veneris

Two new migrated hopane triterpenoids, viz. 4alpha-hydroxyfilican-3-one and fern-9(11)-en-12beta-ol, and olean-18-en-3-one and olean-12-en-3-one as the first example of oleanane compounds from Adiantum ferns were isolated along with many other known triterpenoids from Adiantum capillus-veneris of China and Egypt. Their structures were elucidated by spectroscopic analyses.     

Sequential ring-opening of trans-1,4-cyclohexadiene dioxide for an expedient modular approach to 6,7-disubstituted (±)-hexahydro-benzo[1,4]oxazin-3-ones

A modular approach to novel 6-amino-7-hydroxysubstituted hexahydro-benzo[1,4]oxazin-3-ones has been developed. The method involves a sequential ring-opening of trans-1,4-cyclohexadiene dioxide with amino nucleophiles. The resultant mono-epoxide from benzylamine was converted to a general electrophilic precursor, which enables the parallel treatment with amino nucleophiles to obtain a series of cyclohexane-fused morpholin-3-ones.     

Mitogenic potential inducible by He:Ne laser in human lymphocytes in vitro

The objective of the study was to investigate the mitogenic and genotoxic effects of He:Ne laser irradiation (632.8 nm) on human peripheral lymphocytes in vitro. We used the cytokinesis-block micronucleus assay, which incorporates cytochalasin B to inhibit cytokinesis while karyokinesis proceeds normally leading to the appearance of proliferating lymphocytes as binucleated cells. Also micronuclei will appear in cases of genotoxicologically-affected cells. Buffy coat leukocytes were exposed to 10 mW He:Ne laser at energy densities of 1, 2, 3 and 5 J/cm(2). Cells were then cultured in media 199 without any supplementation for 24, 48, 72 and 96 h adding cytochalasin B 24 h before harvesting of cells. Our results showed that laser-induced lymphocytes proliferate throughout the four consecutive days post-laser irradiation. The difference in the frequency of micronuclei between pre- and post-laser irradiation indicates that a He:Ne laser at such energy densities 1, 2, 3 and 5 J/cm(2) does not induce micronucleus formation. These results shed some light on the mechanism encountered by lymphocytes in the process of He:Ne laser-induced biostimulation.     

Chemistry of quinuclidines as nitrogen bicyclic bridged‐ring structures

This review summarises the structure, basicity, asymmetric organocatalysis, synthesis and reactions of quinuclidines. Quinuclidines are bicyclic saturated pyridin‐containing compounds with rigid structures and a ring‐juncture nitrogen atom. This review covers the period from 1984–2005.     

Numerical simulation for reactive solute transport of arsenic in permeable reactive barrier column including zero-valent iron

Numerical modeling was developed in one dimensional solute transport including chemical reaction to simulate the permeable reactive barrier column results, in which arsenite (As(III)) was removed using zero-valent iron (ZVI). Removal principles of As(III) includes oxidation of As(III) to As(V), sorption of As(III) and sorption of As(V) at least. Each kinetic parameter was drawn in preliminary batch tests to integrate the simulation.     

Synthesis of poly(vinyl alcohol-graft-hyperbranched glycerol)

We report the first example of grafting hyperbranched polyglycerol onto poly(vinyl alcohol) via ring-opening polymerisation of glycidol to prepare poly(vinyl alcohol-graft-hyperbranched glycerol) (P[(VA)-g-(hPG)]). The effects of catalyst, molecular weight of PVA, reaction temperature, water content, moles of reagent, and addition time of reagent were also investigated. P[(VA)-g-(hPG)] with various mole fractions of hPG were prepared and the degrees of substitution and branching were determined. P[(VA)-g-(hPG)] displayed decreased degree of crystallinity and also increased solubility in water, compared to PVA. P[(VA)-g-(hPG)] is shown to be a superior hair styling polymer with a curl retention value of 85% after 4 h. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3041–3047     

Green chemistry: Analytical and chromatography

Nowadays, the environment protection and the personal health and safety are given more consideration in the field of chemistry, thus resulting in an increased number of published researches about how to work according to green instructions, to follow up the recommendations of environmental agencies and to obtain better clean handling of chemistry. In this review, green chemistry definition, importance, principles, and some recent applications in the field of green chemistry were discussed. In addition, the review summarizes the evolution of green analytical chemistry (GAC) with its specific principles and how to make the analytical process more environmentally benign with special emphasis on recent applications of GAC. Moreover, the green chromatography, its methods, and some of its applications were outlined. Finally, different techniques available up till now for the assessment of greening of the methods were also presented.