Electrochemical Hydrogenation of Substituted α-Phenylvinylphosphonic Acids: General Characteristics of the Reaction Layer and Prediction of Preparative Electrolysis Conditions

The conditions for electrochemical hydrogenation and anodic oxidation of -phenylvinylphosphonic acid and its 4-chloro- and 4-methyl-substituted derivatives on palladized platinum electrodes in aqueous sulfuric-acid solutions are found. It is shown that, in the system under study, the products of strong chemisorption are not the intermediates of the electrocatalytic hydrogenation. The reactant molecules are modeled by quantum-chemical methods in terms of the restricted Hartree–Fock approximation. The calculated charge distributions in reactant molecules are used for estimating the electrostatic components of works of approach and the orientation distributions in the reaction layer.     

Nonempirical estimation of the ionization conditions of water and amorphous ice

Based on the results of nonempirical dynamics simulations of the vibrationally excited water clusters combined with the data on the dynamic reorganization of water cations obtained upon the vertical ionization of neutral clusters at the additional assumptions about the general rigidity of the hydrogen-bond fragments in amorphous ice and the thermal excitation of rotational vibrations and swinging motions of molecules in liquid water, the characteristic times of structure reorganization are estimated. The possibility to evaluate the photoelectric threshold of amorphous ice from the data about the adiabatic ionization of small water clusters, whose structure reorganization upon the electron removal does not involve opening of rings and formation of chains, is founded. It is shown that the conditions of the threshold ionization of liquid water can be judged from the second intermediate ionization potentials of neutral clusters, that is, from the potentials corresponding to the appearance of cations in which H₃O and OH fragments are separated with one water molecule. Based on an analysis of the electron density distribution in the cationic and neutral water clusters, a functional dependence of the ionization potentials on the number of water molecules is derived. Approximations of the calculated full adiabatic and intermediate ionization potentials of clusters comprising up to 12 water molecules provided the photoelectric threshold estimates of water and amorphous ice in close agreement with experiments.     

Efficient system of higher education: The role of state

It is proposed to define efficiency as the productivity, which means creation of the necessary and useful products of due quality in the necessary and sufficient amount, at the optimal result/cost ratio. Criteria proposed by the ministry of education and science of the Russian Federation for the estimation of the efficiency of universities are analyzed, as well as the methodological basis of the Thomson Reuters university ranking. It is noted that the efficiency of not only universities, but also the ministry can be estimated only when infrastructural and financial conditions for the efficient work of the university staff are provided and the state goals in the sphere of education are formulated. The ministry should determine the state demand in the sphere of specialist training and provide universities with everything necessary for that, while the universities should duly teach and train those specialists to be. A conclusion is made that national priorities in the field of education and science should be shifted.     

Foreword

Structural Chemistry - Milestones of historical evolution of the Chemistry Department of the Lomonosov Moscow State University, which was formally separated from the physical-mathematical faculty...     

Repeated Elements of the Structure of Liquid Monoethanolamine

For the first time, in F-structures of liquid monoethanolamine that were constructed by molecular dynamics simulations at various temperatures, repetition of structural triangles formed by hydrogen-bonded coordinating atoms (O and N) was revealed. A correlation was found between the revealed features of the molecular dynamics structures and the characteristics of monoethanolamine clusters determined by quantum mechanical calculations. It was shown that there are two main types of triangular motifs that ensure strong binding in the system owing to peculiarities of the electron distribution.     

The problem of small negatively ionized water clusters

Structures of the negatively charged water clusters (H₂O)⁻_n with n up to 6 were optimized at the UHF/4–31 + + G** level without any geometrical restriction. There was found a chainlike structure for the trimer anion and both chainlike and cyclic geometries for the larger clusters. According to the MP2 energy estimates, all the clusters with n ≥ 3 are more stable than the combinations of separated water molecules and a free electron. The energy of the cycles is lower than that of the chains of the same size. However, the latter species are energetically closer to the neutral oligomers of the same geometry. The energy of vertical detachment of an electron from the chainlike hexamer anion is already about zero. Addition of a diffuse s function centered equidistantly between the oxygen atoms proved metastability, in particular, of the cyclic (H₂O)⁻₄ structure. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 737–748, 1997     

Stationary states and dissociation of H<Subscript>3</Subscript>O radical in water clusters

The ground and low-lying excited states of H₃O(H₂O) _k radicals are studied. The character of the unpaired electron localization in the systems is analyzed, and the relative probability of the radical dissociation onto a water cluster and atomic hydrogen is estimated. Reaction coordinates of the dissociation are constructed and conditions of metastable existence of an H₃O radical are determined. Structures, in which H₃O can spontaneously dissociate, are found. Lifetimes of H₃O(H₂O) _k clusters before the hydrogen atom detachment at the initial conditions of two kinds, namely, upon the vertical attachment of an electron to H₃O⁺(H₂O) _k cations and upon the vibrational excitation of metastable neutral H₃O(H₂O) _k systems, are estimated.     

Comparative analysis of the state of lithium and sodium atoms in water clusters

Structures and energetic characteristics of Li(H₂O) _n and Li⁺(H₂O) _n clusters with n = 1–6, 19, and 27 determined in the second order of the Møller-Plesset perturbation theory with 6–31++G(d,p) basis set are analyzed. The electron density redistribution, which takes place upon the electron addition to a Li⁺(H₂O) _n cluster, is found to be provided by hydrogen-bonded water molecules: initially almost neutral molecules, which are most distant from lithium, become negatively charged. The calculated energies of the electron capture by Li⁺(H₂O) _n clusters are approximated with the appropriate electrostatic model, and estimates of the lithium ionization energy in water clusters of various sizes are found. Similar estimates obtained earlier for sodium are made more accurate.