Molecular recognition in a heteromolecular radical pair system with complementary multipoint hydrogen-bonding

Stable radicals 2-(6-uradinyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-1-oxyl (Ur6IN) and 4-(p-tert-butylaminoxylphenyl)-2,6-di(propylamido)pyridine (DAPPN) form heterospin radical pair complexes due to complementary multi-point hydrogen-bonds.     

Magnetostructural study of 2-(4-N-tert-butylaminoxylphenyl)benzimidazole

The heat capacity of the title organic free radical, PhBABI, was measured over 0.3-300 K by adiabatic calorimetry and relaxation methods in the presence of external magnetic fields up to 9 T. A hump in the magnetic heat capacity was observed with a maximum at about 15 K in zero field, which did not shift at fields up to 9 T. The experimental magnetic entropy was in good agreement with the theoretical value of R ln 2 (= 5.76 J K(-1) mol(-1)) for S = 1/2 systems. The higher temperature, field-insensitive feature was fitted to several antiferromagnetic Heisenberg models. The best fits were obtained using spin ladder and coupled spin bilayer models.     

Theoretical chemistry of gold. III

Gold is an element whose unique properties are strongly influenced by relativistic effects. A large body of appropriate calculations now exists and its main conclusions are summarized in this critical review. The present paper completes the recent reviews by Pyykk? (2004, 2005) (529 references).     

Removable sets for Sobolev spaces

We study removable sets for the Sobolev spaceW ^1,p. We show that removability for sets lying in a hyperplane is essentially determined by their thickness measured in terms of a concept ofp-porosity. The author was partially supported by the NSF and the Academy of Finland, SA-34082.     

Linear HThThH: a candidate for a Th-Th triple bond

The acetylene-like linear HThThH structure is calculated to lie almost degenerate to its rhombic alternative. Its unsupported Th-Th triple bond would be the first one of its kind.     

A raw material shortage model of the Finnish chemical industry

At the beginning of 1975 the Federation of the Finnish Chemical Industry and the University of Helsinki, Department of Computer Science, set up a project to develop a mathematical model to be used as a planning tool during accidental raw material shortages in the Finnish chemical industry. The model has been designed, programmed, and tested. The main part of the system consists of a linear programming model, which is used to answer “what-if” questions.This paper describes the model, the programs and the main problems encountered in the design process. The present version of the system can solve problems involving at most 100 firms, 400 products, 400 types of raw materials and 200 technical or policy constraints.     

A note on nodal structures,partial screening,and periodic trends among alkali metals and alkaline earths

The first ionization potential of Na is close to that of Li but much larger than that of K. Similar trends were noted for the electronegativities or for the calculated atomic charges in partially covalent alkali metal hydrides MH or methide compounds, MCH₃ (M=Li–Cs) by Lambert, Kaupp, and Schleyer. This trend can be understood by combining the effects of the nodal structure, as function of the principal quantum number, n, and the lanthanide contraction‐like effects of partial screening from both the 1s and 2p shells. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001     

Thermodynamics,Charge Transfer and Practical Considerations of Solid Boosters in Redox Flow Batteries

Solid boosters are an emerging concept for improving the performance and especially the energy storage density of the redox flow batteries, but thermodynamical and practical considerations of these systems are missing, scarce or scattered in the literature. In this paper we will formulate how these systems work from the point of view of thermodynamics. We describe possible pathways for charge transfer, estimate the overpotentials required for these reactions in realistic conditions, and illustrate the range of energy storage densities achievable considering different redox electrolyte concentrations, solid volume fractions and solid charge storage densities. Approximately 80% of charge storage capacity of the solid can be accessed if redox electrolyte and redox solid have matching redox potentials. 100 times higher active areas are required from the solid boosters in the tank to reach overpotentials of <10 mV.