Ru-Based -Selective Metathesis Catalysts with Modified Cyclometalated Carbene Ligands.

A series of cyclometalated -selective ruthenium olefin metathesis catalysts with alterations to the -heterocyclic carbene (NHC) ligand were prepared. X-Ray crystal structures of several new catalysts were obtained, elucidating the structural features of this class of cyclometalated complexes. The metathesis activity of each stable complex was evaluated, and one catalyst, bearing geminal dimethyl backbone substitution, was found to be comparable to our best -selective metathesis catalyst to date.

Structural biology: 'seeing' crystals the XFEL way.

X-ray free-electron lasers (XFELs) offer opportunities beyond classic X-ray crystallography, particularly for proteins that are difficult to crystallize.

High-security labs: Life in the danger zone.

Instruments for studying microbes under biological containment cannot be readily removed from labs for servicing. A US facility is finding ways around that problem.