Andrey V. Maleev

Results of the X-ray diffraction study of the crystal structure of (1S,3S)-1-tert-butyl-3-methyl-1-phenyl-1,3-dihydro-2-benzofuran and also its comparison with the crystal structure of (1S,3R)-1-tert-butyl-3-methyl-1-phenyl-1,3-dihydro-2-benzofuran that we analyzed previously by X-ray diffraction are presented. By means of the analysis of geometric and energy characteristics of active intermolecular atom-atom contacts substantial distinctions in these structures and the presence of almost the same geometric fragments are reveled in them.

Explicit formulas for coordination sequences of all 20 plane 2-uniform graphs are proved. The proof is based on the concept of layer-by-layer growth and on the canonical representation of geodesic chains in terms of special chains called as rays. The method works for a wide class of plane periodic graphs satisfying the following condition: for each sector of layer-by-layer growth there exists a graph vertex that is initial for two rays determining the sector. This generaizes the previous results where it is required that all vertices are initial for all rays.

Three-component condensation of benzylideneacetone, ethyl acetoacetate, and malononitrile in the 1:1:1 molar ratio, respectively, in the presence of equimolar quantities of piperidine and glacial acetic acid is studied. The crystal structure of the reaction product (ethyl-2-dicyanomethylene-4-methyl-6-phenyl-3-cyclohexene-1-carboxylate) determined from XRD data by the method of atom-atom potentials contains energy traps in the form of double planar and double two-sided catchers. The energy traps lead to molecular agglomerates occurring in the crystal in the form of slightly deformed translationally identical hexagonal networks.

The layer-by-layer growth of Ammann-Beenker graph (a quasi-periodic graph with eightfold symmetry) has been experimentally and theoretically studied. The limiting form for the growth of Ammann-Beenker graph is established in the form of a regular octagon, whose vertices are found explicitly. The lower and upper bounds of this form, which coincide with the growth form, are proven rigorously.

The vertex graph of the Ammann–Beenker tiling is a well-known quasiperiodic graph with an eightfold rotational symmetry. The coordination sequence and coordination shells of this graph are studied. It is proved that there exists a limit growth form for the vertex graph of the Ammann–Beenker tiling. This growth form is an explicitly calculated regular octagon. Moreover, an asymptotic formula for the coordination numbers of the vertex graph of the Ammann–Beenker tiling is also proved.

A new description of Penrose tiling, based on parameterization of tiling rhombuses, has been obtained. A method making it possible to describe clusters and coordination environments in...

The (R)-configuration of the carbinol center formed as a result of diastereospecific reduction of (2S)-2-{2-(1S)-1-(dimethylamino)ethyl]phenyl}-2-hydroxy-1,2-diphenylethanone is established by the...

As a result of triple condensation of malonodinitrile with benzaldehyde and ethyl 2-chloro-3-oxobutanoate a compound with 3-azabicyclo[3.1.0]hexane framework is formed whose crystal structure is...

Изучена трехкомпонентная конденсация бензилиденацетона, ацетоуксусного эфира и малононитрила в мольном соотношении 1:1:1 соответственно, в присутствии эквимолекулярных количеств пиперидина и ледяной уксусной кислоты. В кристаллической структуре продукта этой реакции этил-2-дицианметилен-4-метил-6-фенил-3-циклогексен-1-карбоксилата, определенной РСА, с использованием метода атом-атомных потенциалов выявлены энергетические ловушки в виде двойных плоских и двойных двухсторонних захватов. За счет этих энергетических ловушек в кристалле формируются молекулярные агломераты в виде незначительно деформированных трансляционно идентичных гексагональных сеток.

Методом РСА установлена (R)-конфигурация карбинольного центра, образовавшегося в результате диастереоспецифичного восстановления (2S)-2-{2-(1S)-1-(диметил­амино)этил]фенил}-2-гидрокси-1,2-дифенилэтанона. Анализ укороченных невалентных внутримолекулярных контактов показал, что молекулу можно считать достаточно жесткой, несмотря на наличие в ней большого числа одинарных валентных связей. Обнаружен слоистый характер молекулярной упаковки.