Inorganic Molecular Electride Mg4O3: Structure,Bonding, and Nonlinear Optical Properties

Growing demands of material science and, in particular, in the field of nonlinear optics (NLO) encourage us to look for stable highly polarizable molecules with excess diffuse electrons. An unusual class of compounds called electrides comply with these requirements. Many attempts have been made, yet only few electrides have been synthesized as solids and none of them as molecular species. In this paper, a new theoretically designed molecular species with electride characteristics is reported. The idea of this molecular electride comes from the formation of electride-like features in the MgO crystal with defect F-centers. The geometry of the investigated molecule can be described as a Mg₄O₄ cube with one oxygen atom removed. In Mg₄O₃, two 3s electrons are pushed out from the inner area of the molecule forming a diffuse electride multicentered bond. Our calculations show that this electride-like cluster possesses a noticeably large first hyperpolarizability β=5733 au. At the same time, a complete cube Mg₄O₄ and Mg₄O₃²⁺ without electride electron pair have much smaller β: 0 au and 741 au, respectively. This fact indicates the decisive role of the electride electron pair in NLO properties. Additionally, vertical detachment energies of isomers (VDE), excitation energies ΔE, polarizabilities α, and IR spectra were calculated. These properties, including β, are supposed to be observable experimentally and can serve as indirect evidence of the stable molecular electride formation.     

Water-soluble proteins as an excipient for drug administration by inhalation

Microspherical particles of composite drugs based on lysozyme and albumin, which can be used in inhalation administration, were prepared by spray drying. The composition of the complexes was determined using experimental and theoretical methods. The use of the protein matrix makes it possible to increase the dissolution rate of the drug in water. The obtained results can be useful for the development of new drug dosage forms with increased bioavailability.

     

Reply to the Comment on “Realization of Lewis Basic Sodium Anion in the NaBH3− Cluster”

We reply to the comment by S. Pan and G. Frenking who challenged our interpretation of the Na^?:→BH₃ dative bond in the recently synthesized NaBH₃^? cluster. Our conclusion remains the same as that in our original paper ( https://doi.org/10.1002/anie.201907089 and https://doi.org/10.1002/ange.201907089 ). This conclusion is additionally supported by the energetic pathways and NBO charges calculated at UCCSD and CASMP2(4,4) levels of theory. We also discussed the suitability of the Laplacian of electron density (QTAIM) and Adaptive Natural Density Partitioning (AdNDP) method for bond type assignment. It seems that AdNDP yields more sensible results. This discussion reveals that the complex realm of bonding is full of semantic inconsistencies, and we invite experimentalists and theoreticians to elaborate this topic and find solutions incorporating different views on the dative bond.     

Numerical solution of the variational Rayleigh problem of gas lubrication theory

The three-dimensional variational problem of the optimization of the microgeometry of a gas-lubricated bearing with respect to the maximum lift criterion is considered. The pressure field in the gas film is determined using the Dirichlet boundary-value problem for the gas lubrication Reynolds equation. The results of the numerical solution of the variational problem based on the consideration of the first variation of a functional are presented. The calculation results are presented for a wide range of the problem parameters.St. Petersburg. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 6, pp. 31–38, November–December, 1995.     

All solid-state battery based on ceramic oxide electrolytes with perovskite and NASICON structure

The Li_0.33Lia_0.56TiO₃ and Li_1.3Ti_1.7Al_0.3(PO₄)₃ ceramics with the structures of defect-perovskite and NASICON structures with conductivity of 1–6?×?10^?6 S/cm at the room temperature are obtained. Ceramic electrolytes were developed for a solid-state battery EMF of 4.1 V and high discharge stability in time. Discharge characteristics of solid-state batteries are studied in a laboratory cell.     

Structural Specific Features of Solid Solutions NdxGd1 – xCr3(BO3)4

Optics and Spectroscopy - Optical investigations of crystals of solid solutions NdxGd1 – xCr3(BO3)4, 0.01 ≤ x ≤ 1, have been performed. Absorption spectra in the...     

Electrochemical method for producing radionuclide Lu-177 with high specific activity

A modified method for the isolation of radionuclide ¹⁷⁷Lu obtained from a Yb-176 target irradiated with thermal neutrons is proposed. The method consists of the combination of two electrochemical processes— cementation of ytterbium acetate–chloride solution to sodium amalgam and subsequent electrolysis of the ytterbium solution in a separate electrolytic cell without adjusting the solution. The electrochemical setup consisting of two cells gives the purification factor of ¹⁷⁷Lu from ytterbium at a level of 10⁵–10⁶, which allows using ¹⁷⁷Lu of such quality for labeling bioorganic molecules.