Bis(1,1,1,3,5,5,5-heptafluoro-4-iminopent-2-ene-2-aminato)copper(<Emphasis Type="SmallCaps">ii</Emphasis>) — a new metal-containing matrix in the design of heterospin systems

The first heterospin compounds based on bis(1,1,1,3,5,5,5-heptafluoro-4-iminopent-2-ene-2-aminato)copper(ii) (CuL₂) and nitronyl nitroxide radicals, 2-R-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyls (NIT-R, where R = H, Me, Ph, and 1-methylpyrazol-4-yl), were synthesized and structurally characterized. An important peculiarity of the structure of synthesized solid phases is the formation of a supramolecular structure due to hydrogen bonds between the oxygen atoms of the nitronyl nitroxide fragments of NIT-R and the hydrogen atoms of the NH groups of CuL₂.     

Comparative theoretical and experimental analysis of hydrocarbon σ-radical cations

The structures of σ-radical cations formed by ionization of adamantane, twistane, noradamantane, cubane, 2,4-dehydroadamantane, and protoadamantane were optimized at the B3LYP, B3LYP-D, M06-2X, B3PW91, and MP2 levels of theory using 6-31G(d), 6-311+G(d,p), 6-311+G(3df,2p), cc-PVDZ, and cc-PVTZ basis sets. On the whole, single-configuration approximations consistently describe the structure and transformations of the examined σ-radical cations. The best correlations (r = 0.97–0.98) between the calculated adiabatic ionization potentials and experimental oxidation (anodic) potentials of hydrocarbons were obtained in terms of B3PW91 approximation.     

Reactivity of N-(1,2,4-triazolyl)-substituted 1,2,3-triazoles

Synthetically useful rhodium(II) carbenes were obtained from N-(1,2,4-triazolyl)-substituted 1,2,3-triazoles and Rh(II) carboxylates. The electron-withdrawing 1,2,4-triazolyl group reveals the heretofore unknown reactivity of nonsulfonyl 1,2,3-triazoles, which exhibit the reactivity of diazo compounds. The resulting carbenes provide ready asymmetric access to secondary homoaminocyclopropanes (80-95% ee, dr >20:1) via reactions with olefins and also engage in efficient transannulation reactions with nitriles.     

Comparison of Various Options for Designing the Direct Oxidation of Methane to Methanol

Russian Journal of Applied Chemistry - Various options for designing the direct oxidation of natural gas to methanol are considered: flow-through, with a distributed supply of the oxidizer along...     

A very large diversity space of synthetically accessible compounds for use with drug design programs

We have constructed a very large virtual diversity space containing more than 10¹³ chemical compounds. The diversity space is built from about 400 combinatorial libraries, which have been expanded by choosing sizeable collections of suitable R-groups that can be attached to each link point of their scaffolds. These R-group collections have been created by selecting reagents that have drug-like properties from catalogs of available chemicals. As members of known combinatorial libraries, the compounds in the diversity space are in general synthetically accessible and useful as potential drug leads. Hence, the diversity space can be used as a vast source of compounds by a de novo drug design program. For example, we have used such a program to generate inhibitors of HIV integrase enzyme that exhibited activity in the micromolar range.     

Free-radical reactions of methyl trifluoropyruvate with aldehydes

Methyl trifluoropyruvate reacts with aldehydes in the presence of catalytic amounts of benzoyl peroxide at 130–140°C to give β,β,β-trifluoro-α-(methoxycarbonyl)ethyl carboxylates. UV irradiation makes oligomerization of the initial ketoester predominant. Deceased. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1763–1766, September, 1998.     

Structural defects in molecular crystals based on heterospin copper complexes

Jumplike changes in the microhardness, sample dimensions, and parameters of the EPR spectrum were observed in molecular Cu(hfac)₂L^Et crystals undergoing a phase transition. Defects that appear upon plastic deformation (e.g., dislocations) and paramagnetic defects were revealed. The latter defects are likely breaks in polymer chains and can serve as spin marks for investigating the magnetic state of the crystal lattice.     

Electronic structure and models of receptor of monooxygenase inductors from a number of polychlorinated polycyclic compounds. 2. Calculation of substrate-receptor pairs in perturbation-theory approximation

A theoretical quantum-chemical analysis of the interaction of xenobiotics of the dioxin type with a model of their receptor in the ground state supports the possibility of forming rather stable substrate-receptor pairs, with not only oxidized but also reduced cytochrome P-450. General features have been identified in the interaction of the most dangerous xenobiotics of the dioxin type with the model of their receptor.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2540–2544, November, 1989.