Paracyclophanes as model compounds for strongly interacting π-systems. Part 2: mono-hydroxy[2.2]paracyclophane

The structure of the electronic ground- and first excited state of mono-hydroxy [2.2]paracyclophane (MHPC) and the S(1)← S(0) electronic transition have been investigated by resonance-enhanced multiphoton ionisation (REMPI) and by quantum chemical spin-component-scaled-approximate coupled cluster second order (SCS-CC2) computations. The origin of the S(1)← S(0) transition was located at 30,772 cm(-1) (3.815 eV) in the REMPI spectrum. The value has to be compared with a computed excitation energy of 3.79 eV. The vibrational structure of the spectrum confirms a significant geometry change upon excitation along the coordinates corresponding to twist- and shift-motions in the molecule. It gives rise to an experimentally observed progression with a fundamental of +30 cm(-1) and an inverse anharmonicity. From the experimental data a shallow potential along the twist coordinate was derived for the S(1) state. For the shift vibration a wavenumber of +91 cm(-1) was observed, while +85 cm(-1) was computed. The ionisation energy of MHPC was determined to be 7.63 ± 0.05 eV using synchrotron radiation. When compared to earlier results on the parent compound [2.2]paracyclophane and pseudo-ortho-dihydroxy[2.2]paracyclophane it can be seen that already small variations in the substitution pattern have a significant impact on the shapes of the involved potential energy surfaces leading to strong variations in ground and excited state geometries and opto-electronic properties governing the exciton transfer processes.     

Variability of essential oils of Betonica officinalis (Lamiaceae) from different wild populations in Kosovo

The aerial parts and roots of Betonica officinalis were collected from three localities characterized by different ecological conditions to study the natural variability of the chemical composition of the essential oils in this plant. The leaves and inflorescences were collected during the flowering time, whereas the roots were collected at the end of the vegetative period. The plant material was dried at room temperature. The essential oils were obtained by micro-steam hydrodistillation and analyzed using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Overall, 69 constituents were identified in all localities and plant parts. The main compositions of the leaves in all localities were alpha-pinene, 1-octen-3-ol, beta-bourbonene, (E)-caryophyllene and germacrene D. The essential oil of the inflorescences was characterized by these main constituents: alpha-pinene, (E)-caryophyllene and trans-beta-farnesene. In all localities, the percentages of alpha-pinene and (E)-caryophyllene were higher in the inflorescences than in the leaves, whereas nonane was the main constituent in the roots.     

Tetra‐μ2‐acetato‐diacetatodi‐μ3‐hydroxido‐tetrakis[piperidinecopper(II)] dihydrate

The title complex, [Cu₄(C₂H₃O₂)₆(OH)₂(C₅H₁₁N)₄]·2H₂O, possesses an unusual inversion‐symmetric tetranuclear copper framework, with each Cu^II atom displaying a square‐pyramidal geometry and one additional long Cu...O contact. The four piperidine ligands are terminal, one at each Cu^II atom, and the two hydroxide ligands are triply bridging. The six acetate ligands exhibit two distinct coordination modes, namely as two monodentate acetates and four bridging acetates that bridge the two inequivalent copper centres. The noncoordinating acetate O atom is involved in intramolecular hydrogen bonding with H atoms from the hydroxide and one piperidine ligand. In addition, extensive intermolecular hydrogen bonding involving the solvent water molecules is observed.     

Hydrodynamic and mass transfer characteristic of a novel grid-structured plastic packing

The hydraulic and mass transfer characteristic of a novel grid-structured plastic packing is presented. The geometry of this structured packings differ substantially from conventional corrugated structured packings resulting in an open structure which enables a free exchange of vapour and liquid also in horizontal direction. The hydraulic performance has been measured by air–water experiments in a 440 mm diameter column, the mass transfer characteristic has been determined with the absorption system ammonia–air–water. Is is shown that the grid-structured plastic packing is highly efficient, particularly in terms of the hydraulic capacity compared with random plastic packings. Beside this, the main advantage of the packing is the easy handling and installation as well as the low investment costs compared to the well-known conventional corrugated structured packings.     

Sobolev type inequalities for rearrangement invariant spaces

In the setting of rearrangement invariant spaces, optimal Sobolev inequalities (via the gradient) are well understood. By means of an alternative functional, we obtain new Sobolev inequalities which are finer than (and not necessarily equivalent to) the ones mentioned above.     

A ruled residue theorem for function fields of conics

The ruled residue theorem characterises residue field extensions for valuations on a rational function field. Under the assumption that the characteristic of the residue field is different from 2 this theorem is extended here to function fields of conics. The main result is that there is at most one extension of a valuation on the base field to the function field of a conic for which the residue field extension is transcendental but not ruled. Furthermore the situation when this valuation is present is characterised.     

On Conformally Invariant CLE Explorations

We study some conformally invariant dynamic ways to construct the Conformal Loop Ensembles with simple loops introduced in earlier papers by Sheffield, and by Sheffield and Werner. One outcome is a conformally invariant way to measure a distance of a CLE₄ loop to the boundary “within” the CLE₄, when one identifies all points of each loop.