α-Diketones as acyl anion equivalents: a non-enzymatic thiamine-promoted route to aldehyde-ketone coupling in PEG400 as recyclable medium

By mimicking the peculiar behavior of thiamine diphosphate-dependent acetylacetoin synthase, it has been demonstrated that thiamine hydrochloride 2a and its simple analogue thiazolium salt 2b are able to activate α-diketones as acyl anion equivalents in nucleophilic acylations, such as the homo-coupling of α-diketones and the hitherto unreported cross-coupling between α-diketones and α-ketoesters. These carboligation reactions were optimized under stoichiometric (2a) and catalytic conditions (2b) by using eco-friendly PEG₄₀₀ as the reaction medium, thus allowing both solvent and thiazolium salt recycling.     

Decay of correlations for maps with uniformly contracting fibers and logarithm law for singular hyperbolic attractors

We consider maps preserving a foliation which is uniformly contracting and a one-dimensional associated quotient map having exponential convergence to equilibrium (iterates of Lebesgue measure converge exponentially fast to physical measure). We prove that these maps have exponential decay of correlations over a large class of observables. We use this result to deduce exponential decay of correlations for suitable Poincaré maps of a large class of singular hyperbolic flows. From this we deduce a logarithm law for these flows.     

Simulation of a vacancy defect at the C(111)–2 × 1 surface

The configurations of a vacancy defect on the C(111)–2 × 1 surface, containing atoms with one or two dangling bonds, possessing a high adsorption activity, are calculated. We study the configurations of the vacancy defect at the surface of diamond C(111)–2 × 1 using the semiempirical MNDO method (MOPAC) and the ab initio Hartree–Fock method (PC GAMESS). We calculate the energies of clusters, the orders of atomic bonds, the populations of atomic orbitals, and the localized molecular orbitals.     

Micromotor‐Based Biomimetic Carbon Dioxide Sequestration: Towards Mobile Microscrubbers

We describe a mobile CO₂ scrubbing platform that offers a greatly accelerated biomimetic sequestration based on a self‐propelled carbonic anhydrase (CA) functionalized micromotor. The CO₂ hydration capability of CA is coupled with the rapid movement of catalytic micromotors, and along with the corresponding fluid dynamics, results in a highly efficient mobile CO₂ scrubbing microsystem. The continuous movement of CA and enhanced mass transport of the CO₂ substrate lead to significant improvements in the sequestration efficiency and speed over stationary immobilized or free CA platforms. This system is a promising approach to rapid and enhanced CO₂ sequestration platforms for addressing growing concerns over the buildup of greenhouse gas.