Issue 9

A magazine providing a snapshot of the latest developments across the chemical sciences.

Issue 9

Shape-shifting crystals

Laminated metal-organic frameworks combine flexibility with the robustness of classic zeolites. One such material, [Fe(pydc)(4,4'-bipy)].H₂O, developed by Xiao-Ming Chen and colleagues at Sun Yat-Sen University, China, is able to shrink and grow its internal channels by crystal-to-crystal sliding which changes the crystal packing mode. This phenomenon is triggered by the exchange of guest molecules, dehydration and reabsorption. During these transformations the crystallinity of the material is maintained whilst significant changes in cell-parameter and free-volume are observed.

Boron transport

Scientists in Japan have successfully concentrated boron clusters into the outer layer of fat particles known as liposomes. Traditionally boron has been accumulated inside the liposome, although this new research shows that higher concentrations of boron can be achieved when it is stored in the liposome's outer membrane. These new boron containing particles are stable under physiological conditions. This finding could be invaluable for delivering boron into tumour tissues before boron neutron capture therapy.

Open-tip microchip

Researchers from Uppsala in Sweden have developed a polymer microchip with an open tip for electrospray mass spectrometry. The microchips are fabricated in poly(dimethylsiloxane) and the open tip gives a simple assembly procedure while maintaining a narrow protruding tip. Replication was made in a nickel mould, formed by electroplating a silicon wafer. The electrospray performance of the infused microchips is satisfactory and the easy assembly of coverlid and microchip makes such tips suitable for versatile tests of chip prototypes.

Portable detector

Swiss researchers have reported a microplasma detector for gas chromatographic determination of non-metals in organic compounds. Peter Hauser and Renato Guchardi report a simple arrangement of two cylindrical electrodes clamped with brass electrical connections onto fused silica tubing mounted on a ceramic cube. The miniaturised detector, which is simple to use and build, has low power requirements and is potentially portable for environmental analysis.