Iron Mössbauer spectra of lava from Jeju island and its similarities to Moon basalts

We report the result of measurements of the⁵⁷Fe Mössbauer spectrum for powder samples of lava taken from four widely separated sites on Jeju island. The spectra consist of well defined quadrupole doublets having a 2+ charge state and indicate the presence of olivine, clinopyroxene, and ilmenite. In addition we find a six line magnetically split hyperfine pattern characteristic of impure hematite, with considerable line broadening and reduced internal field. The observed spectra have a remarkable similarity to those found for moon basalts. A recently popularized “collision ejection” model for the moon formation would be consistent with our observations. The data is a particularly simple and direct illustration of the well-known fact that the iron silicates and ilmenite found on the moon are very similar in composition and relative abundance to that found on earth.     

2.2]Paracyclophane/Dehydrobenzoannulene Hybrids: Transannular Delocalization in Open-Circuited Conjugated Macrocycles

No Abstract     

Efficient Bromination of Naphthalene Dianhydride and Microwave-Assisted Synthesis of Core-Brominated Naphthalene Diimides

This article presents an efficient method for the synthesis of core-brominated naphthalene diimides (NDI) from naphthalene dianhydride (NDA). A procedure for monitoring the NDA bromination reaction by ¹H NMR spectroscopy is described, allowing for optimization and greater consistency of this reaction. Furthermore, the subsequent bis-imidization reaction of the brominated NDA product has been significantly enhanced using microwave-assisted conditions, with recovery of pure product via simple filtration in excess of 90% of theoretical yield. This chemistry offers greatly improved methodology for obtaining core-substituted NDI compounds with high efficiency and good yields.     

Polymer brushes on graphene

A critical bottleneck for the widespread use of single layer graphene is the absence of a facile method of chemical modification which does not diminish the outstanding properties of the two-dimensional sp(2) network. Here, we report on the direct chemical modification of graphene by photopolymerization with styrene. We demonstrate that photopolymerization occurs at existing defect sites and that there is no detectable disruption of the basal plane conjugation of graphene. This method thus offers a route to define graphene functionality without degrading its electronic properties. Furthermore, we show that photopolymerization with styrene results in self-organized intercalative growth and delamination of few layer graphene. Under these reaction conditions, we find that a range of other vinyl monomers exhibits no reactivity with graphene. However, we demonstrate an alternative route by which the surface reactivity can be precisely tuned, and these monomers can be locally grafted via electron-beam-induced carbon deposition on the graphene surface.     

Zur Analyse des ?thylalkohols

Ohne Zusammenfassung     

Ion and Molecular Recognition Using Aryl–Ethynyl Scaffolding

The aryl–ethynyl linkage has been extensively employed in the construction of hosts for a variety of guests. Uses range from ion detection (e.g., of metal cations in the environment or industrial waste and of anions prevalent in nature), to molecular mimics for biological systems, and to applications targeting future safety issues (such as CO₂ capture and indicators for the manufacture of chemical weapons). This Focus Review examines the utilization of the aryl–ethynyl linkage in engineering host molecules for a variety of different guests, and how the alkyne unit plays an integral part as both a rigid scaffolding section in host geometry design as well as a linker to allow conjugative communication between discrete π‐electron systems.