Reaction of primary phosphines with elemental sulfur and alkali metal hydroxides (MOH, M = Na, K, Cs): a novel and facile three-component synthesis of trithiophosphonates

Primary phosphines readily react with elemental sulfur and alkali metal hydroxides (MOH, M = Na, K, Cs) in the molar ratio 1:3:2 under mild conditions (70 °C, 0.5 h, ethanol) to afford alkali metal trithiophosphonates in good to high yields (72-90%).     

Chaos and order in stateless societies: Intercommunity exchange as a factor impacting the population dynamical patterns

The once abstract notions of dynamical chaos now appear naturally in various systems [Kaplan D, Glass L. Understanding nonlinear dynamics. New York: Springer; 1995]. As a result, future trajectories of the systems may be difficult to predict. In this paper, we demonstrate the appearance of chaotic dynamics in model human communities, which consist of producers of agricultural product and producers of agricultural equipment. In the case of a solitary community, the horizon of predictability of the human population dynamics is shown to be dependent on both intrinsic instability of the dynamics and the chaotic attractor sizes. Since a separate community is usually a part of a larger commonality, we study the dynamics of social systems consisting of two interacting communities. We show that intercommunity barter can lead to stabilization of the dynamics in one of the communities, which implies persistence of stable equilibrium under changes of the maximum value of the human population growth rate. However, in the neighboring community, the equilibrium turns into a stable limit cycle as the maximum value of the human population growth rate increases. Following an increase in the maximum value of the human population growth rate leads to period-doubling bifurcations resulting in chaotic dynamics. The horizon of predictability of the chaotic oscillations is found to be limited by 5 years. We demonstrate that the intercommunity interaction can lead to the appearance of long-period harmonics in the chaotic time series. The period of the harmonics is of order 100 and 1000 years. Hence the long-period changes in the population size may be considered as an intrinsic feature of the human population dynamics.     

On lovely pairs of geometric structures

We study the theory of lovely pairs of geometric structures, in particular o-minimal structures. We use the pairs to isolate a class of geometric structures called weakly locally modular which generalizes the class of linear structures in the settings of SU-rank one theories and o-minimal theories. For o-minimal theories, we use the Peterzil-Starchenko trichotomy theorem to characterize for a sufficiently general point, the local geometry around it in terms of the thorn U-rank of its type inside a lovely pair.     

A Theory of Electron Transfer in Bridged and Supramolecular Systems

Expressions are derived for the tunnel electric current between two metals produced by the adiabatic transitions of the electrons through a bridge electron level. A new possible physical phenomenon is discussed, viz. electronically driven oscillations of the electron bridge level between two molecular wires.     

A New Approach to Chalcogen–Nitrogen π-Heterocyclic Radicals

This paper gives a brief overview of a new approach to chalcogen–nitrogen heterocyclic π-radicals, particularly 1,2,3- and 1,3,2-benzodithiazolyls, based on thermolysis or photolysis of closed-shell precursors (such as 1,3,2,4-benzodithiadiazines and their 1-Se congeners, 1,2,4,3,5- and 1,3,5,2,4-benzotrithiadiazepines, and some other sulfur–nitrogen rings and cages). The approach allows obtaining radicals hardly accessible or inaccessible in other ways, especially, fluorinated radicals. The identity of radicals prepared is confirmed by electron paramagnetic resonance spectroscopy in combination with density functional theory calculations.     

Studies of one-pot double couplings on dibromoquinolines

In a series of studies, the regioselectivity of Suzuki couplings of dibromoquinolines has been investigated. In general, it is much harder to achieve high levels of regioselectivity in these systems compared to many of the other dibromoheteroaromatics that have been studied. Useful levels of selectivity could be achieved for both a 5,7-dibromoquinoline as well as 3,4-dibromoquinoline. Double Suzuki couplings could also be achieved on these two compounds.     

A novel generation of photoactive comb‐shaped polyamides for the photoalignment of liquid crystals

A new approach to the synthesis of photoactive comb‐shaped homo‐ and copolyamides containing azobenzene, cinnamate, and coumarin side groups for photoalignment of liquid crystals was elaborated. Photooptical properties and photoorientational ability of these polymers with respect to liquid crystals were studied. It was shown that polarized UV irradiation of all spin‐coated polyamides leads to orientation of liquid crystalline molecules deposited on the polyamide thin films. The synthesized polymers containing cinnamate and coumarin side groups as well as azobenzene‐containing cyano‐ and nitro‐substituted polymers demonstrated good orientation ability in relation to liquid crystals displaying photoinduced planar orientation with high dichroism values within the range of 0.68–0.72. Contrary to the above‐mentioned polyamides, azobenzene‐containing fluorosubstituted polymers induced a homeotropic orientation of liquid crystals. It was shown that the synthesized photoactive polyamides can be considered as promising photoalignment materials for application in display technology, photonics, and other “smart” optical devices. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4031–4041