The existing understanding of chemical thermodynamics presupposes that at the same temperature and other conditions being equal, the rate of a chemical reaction will always and everywhere on Earth be constant. We have found that geoelectric field generated by the Earth’s ionosphere, is capable of exerting a strong influence on the rate of chemical processes. Because of the revolution of the Earth around the Sun and varying intensity of the solar irradiance the geoelectric field is highly dynamic and causes the rate of some chemical reactions on the Earth to vary over wide ranges within a year.

The variations of solar activity and distribution of solar energy due to the rotation of the Earth around its axis and around the Sun exert a strong influence on water clusters, as a result of which their chemical reactivity in hydrolytic processes can vary in a very wide range. This phenomenon is well manifested in the hydrolysis of the phosphoric acid esters. 5-Year regular investigations (2015-2019) of the hydrolysis of triethylphosphite in acetonitrile show that the rate of this reaction with all other conditions being equal displays diurnal and annual variations, and is also modulated by the 11-year cycles of solar activity.

ISSN 1025-6415. Допов. Нац. акад. наук Укр. 2019. No 6 It has been recently found that, at constant temperature, concentration, and other conditions being equal, the rate of hydrolysis of triethylphosphite in acetonitrile (Fig. 1) is highly dynamic and varies throughout the year over a very wide range [1]. This was shown by regular measurements started in 2015 (Fig. 2). In January, the reaction was very slow and accelerated twice in February. In March, it slowed down again. In April, it started to grow gradually till the middle of June. At the end of June, a sharp rise occurred, after which a very high rate was established. It lasted two months till the end of August and then slowed down rapidly within two weeks back to the April level. From September, after the autumnal equinox till the end of the year, the average reaction rate declined gradually 2 times more. It is remarkable that, in December, the rate did not return to the level of the beginning of the year and exceeded it about 2-3 times.

This paper considers a conflict situation on the plane as follows. A fast evader E has to break out the encirclement of slow pursuers P j1,...,j n = {P j1,..., P jn }, n ≥ 3, with a miss distance not smaller than r ≥ 0. First, we estimate the minimum guaranteed miss distance from E to a pursuer P a , a ∈ {j 1,..., j n }, when the former moves along a given straight line. Then the obtained results are used to calculate the guaranteed estimates to a group of two pursuers P b,c = {P b , P c }, b, c ∈ {j 1,..., j n }, b ≠ c, when E maneuvers by crossing the rectilinear segment P b P c , and the state passes to the domain of the game space where E applies a strategy under which the miss distance to any of the pursuers is not decreased. In addition, we describe an approach to the games with a group of pursuers P j1,... jn , n ≥ 3, in which E seeks to break out the encirclement by passing between two pursuers P b and P c , entering the domain of the game space where E can increase the miss distance to all pursuers by straight motion. By comparing the guaranteed miss distances with r for all alternatives b, c ∈ {j 1,..., j n }, b ≠ c, and a ∉ {b, c}, it is possible to choose the best alternative and also to extract the histories of the game in which the designed evasion strategies guarantee a safe break out from the encirclement.

Visible light, ultraviolet and x-ray radiation have been found to increase chemical reactivity of water. The irradiated solution of water in acetonitrile reacts with triethyl phosphite considerably faster than the non-irradiated control solution. This phenomenon is accounted for by the decomposition of water clusters under the influence of light with the formation of chemically more active free water molecules.

Several possible reaction pathways are analyzed for the recently studied experimental reaction of diaminocarbenes with aroylimines, where the carbene acted as an oxygen-abstracting agent. A number of structures corresponding to local minima and transition states are located by geometry optimization. In contrast to the more recent interpretation of the mechanism of this process, the reaction does not proceed via the direct formation of the corresponding carbonyl ylide resulted from the electrophilic addition of diaminocarbene to the carbonyl oxygen atom. Two other, more favorable pathways were predicted instead: the nucleophilic attack of the carbene lone pair on the imino nitrogen (pathway "a") or on the carbon atom in the C═N moiety of aroylimine (pathway "b"), in agreement with predictions of the frontier molecular orbital (FMO) theory. Both intermediate adducts undergo a subsequent decomposition onto nitrile ylide and urea. Which of the two pathways becomes preferential depends on the nature of the substituents: pathway "a" is more favored for the experimentally studied species, whereas pathway "b" is thermodynamically preferable for the small-sized model structures.

The negatively charged carbon atom of phosphorus ylides is capable of increasing the nucleophilicity of the triple CN bond. The nitrile group activated in this way can add two equivalents of hexafluoroacetone with the formation of trifluoromethyl substituted 4H-1,2,3-dioxazines. Due to delocalization of the ylidic negative charge one of the C–C bonds acquires a double bond character, the consequence of which is the existence of E/Z-isomerism in these compounds.

A rare example of the addition of sulfur to a phosphaalkene double bond leading to 1,2 lambda(3),sigma(3)-thiaphosphirane 4 is described. The relative accessibility of this compound has allowed the study of some of the chemical properties of the thiaphosphirane ring. The thermodynamic stability of 1,2 lambda(3),s(3)-thiaphosphiranes compared with lambda(5),sigma(3)-phosphoranes has been studied by DFT calculations.

The reactions of 1,3-diphosphaphenalene 3 with sulfur, borane-tetrahydrofuran, and transition metal carbonyls are reported.

An unusual P, P-disubstituted diphosphiranes was prepared and characterized by treatment of 1,8-bis[bis(di-alkylamino) phosphino]naphthalenes HCl followed by Me(4)NF.

Abstract This article summarizes some of our investigations of compounds featuring the structural fragment P‒C‒P. Phosphorus atoms in different oxidation states and coordination numbers display different chemical behaviors. This may lead to unique chemical properties when they are bridged by a methylene group in a P‒CH2‒P system. For example, the PIII‒CH2‒PVunit is able to add different unsaturated compounds to give zwitterionic products with oppositely charged phosphorus atoms. In addition, the two hydrogen atoms in P‒CH2‒P may also take part in different transformations, resulting in the formation of carbodiphosphoranes or in the formation of a direct P-P bond to give three-membered ring diphosphiranes.

Carbanion 4 generated from phosphane azide 3 undergoes intramolecular cyclization to give 1,2,3,4-triazaphosphole 5, which rearranges into 1,2,4-diazaphosphole 8.

Bis(dusopropylamino)carbene can display not only carbene-like reactivity but also enter 1,3-addition reactions with the participation of the carbon and nitrogen atoms of the N-C-N unit

The reaction of 1,8-dilithionaphthalene (1) with methylene-bis[(dialkylamino)chlorophosphanes] [R2N(CI)PCH2P(Cl)-NR2; R = Me (2a), Et (2b)] leads to the formation of new heterocyclic compounds, 1,3-diphospha-2,3-dihydro-1H-phenalenes 3a,b as a mixture of cis and trans isomers, DFT calculations indicate that the cis isomers are thermodynamically more stable by about 1-3 kcal/mol than the trans isomers. Compounds 3a,b can be converted into dithio the derivatives 5a,b and the borane complexes 6a,b, which were characterized by NMR spectroscopy and investigated by X-ray diffraction analysis. The dialkylamino groups in 3 can be substituted by chlorine to give the chlorophosphane 7.

Bis(diisopropylamino)carbene deoxygenates the carbonyl group of aroylimines Ar–C(O)–N=C(CF3)2 to form alkenes, which formally result from the coupling of two carbenes, [Ar–C(:)–N=C(CF3)2] and [(iPr2N)2C:]. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

The P═C ylidic bond of phosphorus ylides is able to dissociate with the formation of the appropriate phosphanes and carbenes. For example, ylide 3 obtained from diphosphane 1 and acyl imines 2 is c...

Bis(diisopropylamino)carbene easily reacts with phthalic anhydride to give quantitatively an isochromane derivative which undergoes unusual isomerization with the formation of a strained azetidine ring and a very short intramolecular hydrogen bond. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).

Oxidation of the ylide (Et2N)(2)Pt[=C(CN)CH(CF3)(2)]CH2P(NEt2)(2) (3) with tetrachloroorthobenzoquinone (TOB) does not give the expected 1,3,2-dioxaphospholane but stops at the formation of the unusually stable intermediate zwitterion 6. The molecular structure of 6 was established by X-ray analysis. In solution at temperatures above 15 degrees C zwitterion 6 undergoes an unusual decomposition into symmetrical carbodiphosphorane 7 and hexafluoroisovaleronitrile 8. (c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007.

The phosphorus ylides RPh(2)p=C(Mes)N=C(CF3)(2) [R = Ph, Ph2P(O)CH2] in solution undergo reversible dissociation of the P=C ylidic bond to give phosphanes RPh2P and the carbene MesC(:)N=C(CF3)(2). The latter can be trapped as its mesomeric nitrile ylide by treatment with cyclohexene or phenyl isocyanate to give cyclic addition products. (c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007.