Cyclization and rearrangements of diterpenoids. IX. Isomerization of (1R,2S,7S,10S,11R,12S,13S)-2,6,6,10,12-pentamethylpentacyclo[10.2.1.01,10.02,7.011,13]pentadecane by fluorosulfonic acid

It has been shown that the opening of the cyclopropane ring in (1R, 2S, 7S, 10S, 11R, 12S, 13S)-2,6,6,10,12-pentamethylpentacyclo[10.2.1.0^1,10.0^2,7.0^11,13]pentadecane takes place under the action of fluorosulfonic acid at all three carbon-carbon bonds, but at low temperatures the main isomerization product is (1R, 2S, 7S, 10S, 12S, 13S)-2,6,6,10,12-pentamethyltetracyclo[10.2.1.0^1,10.0^2,7]pentadecan-13-ol, and at the ordinary temperature the main products are (1R, 2S, 7S, 11S, 12R, 13R)-2,6,6,11,13-pentamethyltetracyclo[10.2.1.0^1,10.0^2,7]pentadeca-9-ene and (1S, 2R, 11S, 12R, 15R)-2,7,7,11,15-pentamethyltetracyclo[10.2.1.0^2,11.0^3,8]pentadeca-3(8)-ene.     

A Coupling Framework for Multi-Domain Modelling and Multi-Physics Simulations

This paper describes a coupling framework for parallel execution of different solvers for multi-physics and multi-domain simulations with an arbitrary number of adjacent zones connected by different physical or overlapping interfaces. The coupling architecture is based on the execution of several instances of the same coupling code and relies on the use of smart edges (i.e., separate processes) dedicated to managing the exchange of information between two adjacent regions. The collection of solvers and coupling sessions forms a flexible and modular system, where the data exchange is handled by independent servers that are dedicated to a single interface connecting two solvers’ sessions. Accuracy and performance of the strategy is considered for turbomachinery applications involving Conjugate Heat Transfer (CHT) analysis and Sliding Plane (SP) interfaces.     

Hydrogen-atom abstraction from Ni(I) phosphido and amido complexes gives phosphinidene and imide ligands

Hydrogen-atom abstraction from M-E(H) to generate M═E-containing complexes (E = PR, NR) is not well studied because only a few complexes are known to undergo such reactions. Hydrogen-atom abstraction from nickel(I) phosphide and amide complexes led to the corresponding phosphinidene and imide compounds. These reactions are unparalleled in the organometallic chemistry of nickel and feature an unusual example of a transition-metal phosphinidene synthesized by hydrogen-atom abstraction.     

Femtosecond midinfrared study of aggregation behavior in aqueous solutions of amphiphilic molecules

We study the spectral and orientational dynamics of HDO molecules in aqueous solutions of different concentrations of tertiary butyl alcohol (TBA) and trimethylamine-N-oxide (TMAO). The spectral dynamics is investigated with femtosecond two-dimensional infrared spectroscopy of the O-H stretch vibration of HDO:D(2)O, and the orientational dynamics is studied with femtosecond polarization-resolved pump-probe spectroscopy of the O-D stretch vibration of HDO:H(2)O. Both the spectral and orientational dynamics are observed to show bimodal behavior: part of the water molecules shows spectral and orientational dynamics similar to bulk liquid water and part of the water molecules displays a much slower dynamics. For low solute concentrations, the latter fraction of slow water increases linearly as a function of solute molality, indicating that the slow water is contained in the solvation shells of TBA and TMAO. At higher concentrations, the fraction of slow water saturates. The saturation behavior is much stronger for TBA solutions than for TMAO solutions, indicating the aggregation of the TBA molecules.     

Comparing first and second price auctions with asymmetric bidders

We study procurement auctions in which, as is common in practice, a group of sellers (incumbents, qualified bidders) is given an advantage, based, for example, on better reliability, quality, or incumbency status. We show conditions under which for any given first price handicap auction, there is a simple second-price design which dominates it. This generalizes a previous result for the case of an auction with one insider and one outsider (Mares and Swinkels in J Econ Theory, 2013) and sharpens our understanding of the classical result by Maskin and Riley (Rev Econ Stud 67:413–438, 2000).     

Nonlinear Instability for the Critically Dissipative Quasi-Geostrophic Equation

We prove that linear instability implies non-linear instability in the energy norm for the critically dissipative quasi-geostrophic equation.     

Study of sensitometric and holographic properties of photoresist media based on carbazole-containing polymers sensitized with triiodomethane and pyran photochromic materials

Sensitometric and holographic properties of photoresist layers made from carbazolylalkyl methacrylate copolymers and polyepoxypropylcarbazole sensitized with triiodomethane and, additionally, spiropyran photochromic compounds were studied. It was found that the introduction of photochromic 6′-bromo-8′-nitro-1,3,3-trimethylindolylspirobenzopyran (8–12%) into photoresist layers increased their photographic sensitivity by a factor of 2.5–3 up to the values of 10^?3–10^?4 J cm^?2 and shifted their spectral sensitivity to the blue-green region. The feasibility of recording quality holograms in the photoresist layers using coherent He-Cd laser light (λ = 420 nm), as well as argon laser light (λ = 490 nm), was shown. Diffraction gratings with an efficiency of 15–20% and a resolution of 2000 mm^?1 were obtained.