Magnetism and EPR Studies of Binuclear Ruthenium Hydride Binuclear Species Bearing Redox-Active Ligands.

The binuclear complex {[N]Ru(H)}(μ-η:η-N) ([N] = 2,6-(ArylN═CMe)CHN and Aryl = mesityl or xylyl) contains two formally Ru(I), d centers linked by a bridging dinitrogen ligand, although the odd electrons are substantially delocalized onto the redox non-innocent pincer ligands. The complex exhibits paramagnetic behavior in solution, but is diamagnetic in the solid state. This difference is attributed to intermolecular "π-stacking" observed in the solid state, which essentially couples unpaired electrons on each half of the complex to form delocalized 22-center-2-electron covalent bonds.

Electrochemistry of Ruthenium Bis(imino)pyridine Compounds: Evidence for an ECE Mechanism and Isolation of Mono and Dicationic Complexes.

The electrochemical properties of a series of ruthenium complexes bearing the redox noninnocent bis(imino)pyridine ligand were investigated with cyclic voltammetry. An unexpected electrochemical feature in one of the complexes indicated a possible electrochemical-chemical-electrochemical (ECE) process. Further investigation into the oxidation mechanism included the synthesis and isolation of cationic and dicationic analogues of the complex.

The effect of neat ionic liquid on the folding of short peptides.

Using circular dichroism spectroscopy, we show evidence of unusual folding behaviour for several designed peptides in neat ionic liquid. Helical peptides, AKA(2) and Trp-cage, exhibit heat-induced folding, with stable helical structure persisting to 96 °C, whereas the β-hairpin Trpzip4 is destabilized by the neat [C(4)mpy][Tf(2)N].