Inna K. Shundrina

Selective mono-and diamination of polyfluorinated benzenes and pyridines with liquid ammonia

Amination of pentafluoropyridine, 2,3,5,6-tetrafluoropyridine, 4-chlorotetrafluoropyridine, 3,5-dichlorotrifluoropyridine, octafluorotoluene, α,α,α,2,3,5,6-heptafluorotoluene, decafluoro-m-xylene, decafluorobiphenyl, hexafluorobenzene, and pentafluorobenzene with liquid ammonia was investigated. Bis-aminodefluorination temperatures for the majority of substrates were shown to exceed significantly the corresponding temperatures of monoaminodefluorination. The optimal conditions for selective preparation of mono-and diaminopolyfluoro(het)arenes were elucidated. An efficient method for isolation of particular polyfluorophenylenediamines from product mixtures formed in nonselective reactions of pentafluorobenzene and hexafluorobenzene with aqueous ammonia based on complexation with a crown ether is proposed.

Inheritance and phenotype expression of functional and null alleles of aromatic alcohol dehydrogenase (CAD) in diploid wheats

Functional F and null 0 alleles of the CAD1 (Aadh1) gene, which controls the biosynthesis of aromatic alcohol dehydrogenase, were studied in hybrids of the diploid wheat T. monococcum L. and Triticum sinskajae A. Filat. et Kurk. The gene CAD1 is located in chromosome 5A and is linked with the awnless gene awnS (La) with a recombination frequency of about 32%. Plants with genotypes FF, F0, and 00 were significantly different in the height and mechanical strength of the stalk (culm). The elastic limit of the culm tissues of plants FF was considerably higher than in 00 plants. F0 heterozygotes had intermediate values. The thickness of the wall of the sclerenchyma was thinner in plants with genotype 00. The chemical structure of lignin of plants with the functional CAD allele contained units of a phloroglucinol series missing in the mutant plants. The CAD genotypes had no effect on the relative content of cellulose and lignin in stalks of diploid wheat and insignificantly influenced the ratio of H: G: S units in the lignin structure, as well as some components of extractives. IR-spectroscopy found differences in the distribution of components of cell walls and extractives on the outer and inner surfaces of the culm. The results are discussed in relation to the applied aspects of the use of herbal products. Samples of diploid wheat with various genotypes of CAD can be used as model objects in breeding and genetic research.

Synthesis and properties of novel random copolymers made from N-acryloyl piperazine-based monomers and fluoroalkylmethacrylates

New piperazine-based polymerizable monomers were synthesized to modify adhesive properties of fluoromethacrylic copolymer. The new monomers showed good ability to radical copolymerization with fluoroalkylmethacrylates. Amorphous glassy terpolymers were prepared with random distribution units in the macromolecules and weight-average molecular weight (Mw) 110,000–130,000. The ratio of monomer units in the obtained copolymer is close to the ratio of the monomers in the starting mixture. The terpolymers exhibited excellent solubility in tetrahydrofuran (THF), acetone and α,α,α-trifluorotoluene (TFT). The introduction of new monomers to the macromolecules increased the glass-transition temperatures (Tg) of terpolymers, significantly improved their thermal stability and adhesion to the aluminum substrate.

Formation of separating layers under conditions of the thermal aging of sorbents modified by fluorinated polyimide

Thermogravimetry, elemental analysis, low-temperature nitrogen adsorption, high-resolution electron microscopy, and gas chromatography are used to study the effect of the content of perfluorinated polyimide when used as a stationary phase for modifying Chromosorb P NAW diatomite supports and aluminum oxide, and the effect of thermal aging conditions on changes in their texture and chromatographic characteristics. It is shown that Chromosorb P NAW + 5 wt % of polyimide (PI) adsorbent thermally aged at 700°C in a flow of inert gas exhibits properties of carbon molecular sieves, while aluminum oxide impregnated with 10 wt % of PI and thermally aged at 250°C allows us to selectively separate permanent and organic gases, as well separate saturated and unsaturated hydrocarbons.

The Design of Radical Stacks: Nitronyl-Nitroxide-Substituted Heteropentacenes

Abstract The first alkyl chain‐anchored heteropentacene, dithieno[2,3‐d;2′,3′‐d′]benzo‐[1,2‐b;3,4‐b′]dithiophene (DTmBDT), mono‐ or disubstituted with a nitronyl nitroxide group has been prepared through a cross‐coupling synthetic procedure of the corresponding dibromo‐derivative (Br2‐DTmBDT) with a nitronyl nitroxide‐2‐ide gold(I) complex. The synthesized nitroxides possess high kinetic stability, which allowed us to investigate their structure and thermal, optical, electrochemical, and magnetic properties. Single‐crystal X‐ray diffraction of both mono‐ and diradicals revealed that the nitronyl nitroxide group lies almost in the same plane as the nearest side thiophene ring. Such arrangement favors formation of edge‐to‐edge dimers, which then form close π‐stacks surrounded by interdigitating alkyl chains. Before melting, these nitronyl nitroxide radical substituted molecules undergo at least two different phase transitions (PTs): for the monoradical, PTs are reversible, accompanied by hysteresis, and occur near 13 and 83 °C; the diradical upon heating shows a reversible PT with hysteresis in the temperature range 2–11 °C and an irreversible PT near 135 °C. PTs of this type are absent in Br2‐DTmBDT. Therefore, the step‐by‐step substitution of bromine atoms by nitronyl nitroxide groups changes the structural organization of DTmBDT and induces the emergence of PTs. This knowledge may facilitate crystal engineering of π‐stacked paramagnets and related molecular spin devices.

Polymorphism of lignification enzymes in plants: Functional importance and applied aspects

The synthesis of lignin and its deposition in secondary cell walls leads to the formation of sclerenchyma, a tissue having mechanical strength. This biochemical mechanism arose about 400–420 million years ago, in the Early Silurian period, in the first vascular plants (Tracheophyta order). The appearance of sclerenchyma is related to the emergence of plants on land and formation of the terrestrial flora. Lignified tissues of plants also perform conducting and protective functions, in addition to its mechanical (supporting) one. The polymorphic options of the enzymes involved into biosynthesis of lignin and its accompanying substances (PAL (phenylalanine ammonia-lyase), C4H (cinnamate 4-hydroxylase), C3H (p-coumarate 3-hydroxylase), F5H (ferulate 5-hydroxylase), COMT (caffeic acid O-methyltransferase), CCoAOMT (caffeoyl-CoA Omethyltransferase), 4CL (4-coumarate:CoA ligase), CCR (cinnamoyl-CoA reductase), CAD (cinnamyl alcohol dehydrogenase), and SAD (sinapyl alcohol dehydrogenase) were considered with the use of a number of plants: corn, millet, sorghum, rice, wheat, fescue, elephant grass, brachypodium (purple false brome), tobacco, alfalfa, arabidopsis, poplar, eucalyptus, pine, spruce, and ginkgo. Mutant variants of enzymes can be found in natural or breeding populations; they may be also obtained with the use of mutagens. In recent decades, T-DNA-mutagenesis is widely used. Mutations can cause changes in the expression of the corresponding genes and (or) disturb the structure of protein molecules. As a result, numerous changes in the phenotype can occur. Among them are changes in the structure and chemical composition of tissues, as well as in growth processes and plant development. The appearance of colored (brown midrib, reddish brown, pink, red-brown, red-wine, etc.) forms of plants was described in many species. Some publications noted an interrelation between the biosynthesis of monolignols and that of flavonoid pigments. Mutant forms are widely used at present to produce forage cultivars and bioethanol, to improve pulp properties (production of paper and viscose fiber), and to sequester atmospheric carbon. The synthesis of mutants from this group of enzymes and their use are considered promising trends of modern plant biotechnology.

High-temperature adsorption layers based on fluoridated polyimide and diatomite carrier

A way of preparing separation layers by the pyrolysis of fluorinated polyimide obtained from 2,4,6-trimethyl-m-phenylenediamine (2,4,6-TMmPDA) and 2,2-bis(3′,4′-dicarboxyphenyl)hexafluoropropane (6FDA) applied onto a diatomite carrier is described. Thermogravimetry, elemental analysis, low-temperature nitrogen adsorption, high-resolution electron microscopy, and gas chromatography are used to study changes in the texture and chromatographic characteristics of these layers. It is found that changes in the structure and the effectivity of separation characteristic of the layers depend on the temperature of pyrolysis, which ranges from 250 to 1100°C. It is established that a layer of separation is formed at 250–350°C, and the order of elution of hydrocarbons is similar to their chromatographic behavior on such stationary phases as OV-101. Layers of amorphous carbon formed on the surfaces of individual particles on a diatomite surface at 500–700°C. These layers ensure highly stable and selective separation of permanent gases and hydrocarbons when they are present together.

Chromosomal localization of aromatic alcohol dehydrogenase fast-migrating isoenzyme Aadh1F (CAD1-F) gene in Triticum aestivum L. bread wheat

Differences in isoenzyme pattern of aromatic alcohol dehydrogenase, NADP-AADH or CAD, were found in the Triticum aestivum L. winter bread wheat cultivars by the method of electrophoresis in the starch gel. A standard three-component spectrum is present in the cv. Zitnica (former Yugoslavia); additional fact-migrating isoenzymes appear in the cv. Novosibirskaya 9 (Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, Russia). The presence of fast-migrating CAD isoenzymes is designated as FF phenotype; their absence, as 00 phenotype. Hybridological analysis was carried out; the excess of “null” genotypes was found in F2 progenies. Hybridization with nulli-tetrasomic lines of the chromosomes of the fifth homeologous group was conducted for the gene localization. The segregation analysis demonstrated the most probable localization of the CAD1-F gene in the chromosome 5A. The plants with FF and 00 genotypes differed in a number of chemical and anatomical traits, as well as in grain productivity. The results obtained are discussed in connection with the function of this enzyme in the wheat plant tissues.

Physicochemical Properties of Culms in Rye (Secale cereale L.) with a Brittle Stem

In carrying out a genetic analysis of rye in terms of a “brittle stem” trait, sister plants with normal and brittle stems were obtained. The culms of plants were studied in terms of chemical composition, spectroscopic parameters, and mechanical strength. Differences among plants with different types of culm were found in terms of a number of indicators, such as the content of aromatic monomers of lignin and the ratio of different types of chemical bonds. Culms of normal and brittle rye of the same diameter vary in terms of an elastic modulus and elastic deformation limit. It was found that stems of mutant plants are destroyed under lateral stress by means of the fragile fracture mechanism, while those in normal plants are destroyed by ductile fracture. The limits of elastic deformation and strength are significantly higher for normal plants. By nuclear magnetic resonance methods, we detected differences in the chemical structure of lignins in terms of the following: the content of aldehyde and methoxyl groups, total aromaticity, and the number of ordinary ether bonds, by which lignin units are associated with polysaccharide fragments of cellular walls. Higher lignin content in a mutant does not increase the mechanical strength of the culm. On the contrary, there is a decrease in the limits of elastic deformation and an increase in the fragility of the shoots. Probably, the mutation bs, except for direct action (brittleness of the culm), causes an imbalance of metabolic processes in the formation of secondary cell walls and leads to deviations from the optimal ratio of carbohydrate and lignin components. The differences found in various indicators can be used in breeding research associated with important economic traits of cereal stems.

Study on the strength of straw in rye (Secale cereale L.) with the use of the method of the dynamic mechanical analysis

Five indices of the straw strength (elastic module, elastic limit, elastic deformation, ultimate strength, ultimate deformation) have been found for the third and the fourth internodes in mutant (vitreous culm) and normal rye plants. Considerable differences in mechanical properties of culms and in correlation between indices studied in mutant and normal rye genotypes have been revealed. It was shown that the dynamic indices of the mechanical properties can be used for the evaluation of the cereal genotypes in breeding.