Three compounds with phenyl and pentafluorophenyl rings bridged by (CH ) and (CH ) SiMe units were synthesized by hydrosilylation and C-C coupling reactions. Their solid-state structures are dominated by intermolecular π stacking interactions, primarily leading to dimeric or chain-type aggregates. Analysis of free molecules in the gas phase by electron diffraction revealed the most abundant conformer to be significantly stabilized by intramolecular π-π interactions. For the silicon compounds, structures characterized by σ-π interactions between methyl and pentafluorophenyl groups are second lowest in energy and cannot be excluded completely by the gas electron diffraction experiments. C H (CH ) C F , in contrast, is present as a single conformer. The gas-phase structures served as a reference for the evaluation of a series of (dispersion-corrected) quantum-chemical calculations.

We report on the solid-state structures of bis(nonafluoro-tert-butyl) peroxide [(F 3 C) 3 CO] 2 and bis(undecafluoro-2-methyl-2-butyl) peroxide[ (C 2 F 5 )(F 3 C) 2 CO] 2 .T hese peroxides were prepared from the corresponding hypofluorites and fluorinated silver wool. The solid-state structures obtained after in situ crystallisation show unusual COOC dihedral angles of 1808 8,a sw ell as elongated O À Ob onds because of the bulky perfluorinated alkyl groups.T he perfluorinated alkylp eroxides are insensitive to both impact (> 40 J) and friction (> 360 N), and resistant towards mineral acids (HX;X= F, Cl, Br) and elemental halogens (X 2 ). Ferrocene is oxidized by [(F 3 C) 3 CO] 2 to [Fe III Cp 2 ][OC(CF 3 ) 3 ].

The use of penetration enhancers (chemical or physical) has been proven to dramatically improve the penetration of therapeutics. Nevertheless, their use poses great risks, as they can lead to permanent damage of the skin, reduce its barrier efficiency, and result in the intrusion of harmful substances. Among the most used skin penetration enhancers, water is greatly accepted because skin quickly recovers from its exposure. Nanocapsules (NCs) represent a promising combination of the carrier system and penetration enhancer because their water-containing void combined with their polymer-based shell can be used to induce high local skin hydration, while simultaneously aiding the transport of drugs across the skin barrier. In this study, NCs were synthesized with a void core of 100 nm in diameter, a thermoresponsive shell based on different ratios of poly(N-isopropylacrylamide) and poly(N-isopropylmethacrylamide) as thermoresponsive polymers, and dendritic polyglycerol as a macromolecular cross-linker. These NCs can shrink or swell upon a thermal trigger, which was used to induce the release of the entrapped water in a controlled fashion. The interactions and effects of thermoresponsive NCs on the stratum corneum of excised human skin were investigated using fluorescence microscopy, high-resolution optical microscopy, and stimulated Raman spectromicroscopy. It could be observed that the thermoresponsive NCs increase the amount of deuterated water that penetrated into the viable epidermis. Moreover, NCs increased the skin penetration of a high-molecular weight dye (Atto Oxa12 NHS ester, MW = 835 g/mol) with respect to formulations in water or 30% DMSO, emphasizing the features of the NCs as a skin penetration enhancer.

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Mittels Hydrosilylierungs-und C-C-Kupplungsreaktionen wurden drei mit (CH 2 ) 3 -und (CH 2 ) 2 SiMe 2 -Einheiten verbrückte Verbindungen mit Phenyl-und Pentafluorphenylringen synthetisiert. Im Festkçrper bilden sie primärd imere oder kettenartige,v on intermolekularen p-p-Wechselwirkungen dominierte Aggregate.D ie Struktur des häufigsten Konformers der freien Moleküle zeigt jeweils,b estimmt mittels Gas-Elektronen-Diffraktion, eine signifikante intramolekulare Stabilisierung durch p-p-Wechselwirkungen. Die nächstenergiereicheren Konformere fürdie Siliciumverbindungen zeigen s-p-Wechselwirkungen zwischen Methyl-und (Pentafluor-) Phenylgruppen und kçnnen im GED-Experiment nicht vollständig ausgeschlossen werden. Im Unterschied dazu besteht C 6 H 5 (CH 2 ) 3 C 6 F 5 nur aus einem einzigen Konformer.D ie Gasphasenstrukturen dienen als Referenz fürd ie Evaluation einer Reihe (dispersionskorrigierter) quantenchemischerM ethoden.