Effect of electron-ion bombardment on the growth of dielectric films in reactive sputtering

The mechanism by which electron — ion bombardment affects the growth of a silicon nitride film obtained by reactive sputtering in an apparatus based on a Penning discharge is investigated. The temperature and the degree of irradiation of the substrate are determined as functions of the distance from the substrate to the aperture in the anode. It is established that the presence or absence of bombardment leads to a difference in the formation of reactively sputtered silicon nitride films.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 11–15, December, 1976.The authors thank Yu. E. Kreindel' for his interest in the work and for useful discussions.     

N-PtIV-H/N-H...PtII intramolecular redox equilibrium in a product of H-C(sp2) cleavage and unusual alkane/arene C-H bond selectivity of ([2.1.1]pyridinophane)PtII(CH3)+

T-shaped 14 valence electron (eta2-L)PtMe+ (based on DFT geometry optimization, L = [2.1.1]-2,6-pyridinophane) reacts with benzene to give (eta3-L) PtIV(Ph)2H+ and methane; the latter cation is in thermal equilibrium with the N-protonated PtII tautomer (eta2-L-H)Pt(Ph)2+, and these complexes react with ethane or cyclopentane to produce benzene and (L)PtH(olefin)+.     

Synthesis,structure, spectral properties,and electrochemistry of bis(crown ether) containing 1,3-distyrylbenzenes

The reaction of tetraethyl [1,3-phenylenedi(methylene)]bis(phosphonate) with formyl derivatives of benzocrown-ethers or formyl derivatives of o-dimethoxybenzene lead to high yield formation of the respectful bis(crown ether) containing 1,3-distyrylbenzenes or tetramethoxy-substituted 1,3-distyrenebenzenes. NMR spectra and quantum-chemical calculations showed the prevalence of unsymmetrical syn/anti,(syn,anti),syn/anti-conformations in 1,3-distyrylbenzenes. 1,3-Distyrylbenzenes absorb in shorter wavelength spectral region and have a weaker fluorescence than 1,4-distyrylbenzenes. The difficulty in the electrochemical reduction of 1,3-distyrylbenzenes comparing with 1,4-distyrylbenzenes is due to a less effective conjugation system in the metaderivatives.     

Photoprocesses in <Emphasis Type="Italic">N</Emphasis>-ammonioalkyl derivatives of azacrown-containing styryl dyes and their complexes with metal perchlorates

Photophysical processes and photochemical reactions in the N-ammonioalkyl derivatives of the azacrown-containing styryl dyes and their complexes with lead and barium perchlorates in MeCN and CH₂Cl₂ were studied by ¹Н NMR spectroscopy, absorption spectroscopy, luminescence spectroscopy, laser kinetic spectroscopy, and quantum chemistry. Molecules of the styryl dyes and their complexes are able to undergo normal (fast) and delayed fluorescence and trans–cis-photoisomerization. The molecules in the triplet state participate in degradation processes of the electron excitation energy.     

MHD Effects in Continuous Spin Detonation

Doklady Physics - Conversion possibility of the chemical energy of combustion products of a hydrogen–oxygen mixture into electrical energy with the use of continuous spin detonation has been...     

15-Hydroxybenzomonothia-15-crown-5 with the sulfur atom linked with the benzene ring and the derived sulfoxide: synthesis,structure, and complexation with the metal cations

Novel 15-hydroxybenzomonothia-15-crown-5 containing the sulfur atom linked with the benzene ring and its S-oxide were synthesized. The stability constants for the complexes of the obtained benzocrown ethers and a reference 15-hydroxybenzo-15-crown-5 with Na, Ca, Ag^I, Cd, Hg^II, and Pb^II perchlorates were determined by ¹H NMR titration. In MeCN-d₃, the benzothiacrown ether demonstrates a high selectivity towards the thio- and oxothiophilic Hg²⁺ (logK ₁ = 7.1) and Pb²⁺ ions (logK ₁ = 7.4). In MeCN-d₃-D₂O mixtures, the stabilities of the most of complexes decrease sharply due to competitive hydration of the metal cations except for the “soft” Ag⁺ and Hg²⁺ ions having low affinity for the “hard” oxygen atoms and, on the contrary, very high affinity for the “soft” S^II atoms. This results in the change in selectivity of complexation: at the water content in solution of 20%, the benzothiacrown ether binds preferably the Hg²⁺ (logK ₁ = 5.0) and Ag⁺ ions (logK ₁ = 2.7). In MeCN-d₃, the benzothiacrown-derived sulfoxide is a weak and non-selective complexing agent towards all the metal cations under study; the reference 15-hydroxybenzo-15-crown-5 forms more stable complexes with the oxophilic sodium, calcium, and lead(ii) cations. The conformational features of the benzocrown ethers and their metal complexes established by NMR spectroscopy and X-ray diffraction are discussed. The found characteristics of the complexing ability of benzomonothia-15-crown-5 where the sulfur atom is in conjugation with the benzene ring reveal that the macrocyclic ligands with such a structure are promising as high-selective and efficient complexing agents for the “soft” mercury(ii) and silver(i) cations in acetonitrile-water mixtures.     

Nitro derivatives of <Emphasis Type="Italic">N</Emphasis>-alkylbenzoaza-15-crown-5: synthesis,structures, and complexation with metal and ammonium cations

A number of N-alkylnitrobenzoaza-15-crown-5 with the macrocycle N atom conjugated with the benzene ring were obtained. The structural and complexing properties of these compounds were compared with those of model nitrobenzo- and N-(4-nitrophenyl)aza-15-crown-5 using X-ray diffraction, ¹H NMR spectroscopy, and DFT calculations. The macrocyclic N atom of benzoazacrown ethers are characterized by a considerable contribution of the sp3-hybridized state and a pronounced pyramidal geometry; the crownlike conformation of the macrocycle is preorganized for cation binding, which facilitates complexation. The stability constants of the complexes of crown ethers with the NH₄ ⁺, EtNH₃ ⁺, Na⁺, K⁺, Ca²⁺, and Ba²⁺ ions were determined by 1H NMR titration in MeCN-d₃. The most stable complexes were obtained with alkaline-earth metal cations, which is due to the higher charge density at these cations. The characteristics of the complexing ability of N-alkylnitrobenzoaza-15-crown-5 toward alkaline earth metal cations are comparable with analogous characteristics of nitrobenzo-15-crown-5 and are much better than those of N-(4-nitrophenyl)aza-15-crown-5.     

Facile arene C-H bond activation and alkane dehydrogenation with anionic LPt(II)Me2- in hydrocarbon-water systems (L = dimethyldi(2-pyridyl)borate)

Anionic dimethyldi(2-pyridyl)borato dimethylplatinum(II) complexes react vigorously in 3:1 RH/water mixtures to produce PtII aryl (RH = C6H6, para-F2C6H4) or hydrido PtII olefin complexes (RH = cyclo-CnH2n; n = 5,6); the Na+ cation accelerates the reaction rates dramatically.