Zirconium-Nitrogen Intermolecular Frustrated Lewis Pairs.

A series of intermolecular transition metal frustrated Lewis pairs (FLPs) based on zirconocene alkoxide complexes ([CpZr(OMes)] 1 or ([Cp*Zr(OMes)] 2) with nitrogen Lewis bases (NEt, NEtPr, pyridine, 2-methylpyridine, 2,6-lutidine) are reported. The interaction between Zr and N depends on the specific derivatives used, in general more sterically encumbered pairs leading to a more frustrated interaction; however, DOSY NMR spectroscopy reveals these interactions to be dynamic in nature. The pairs undergo typical FLP-type reactivity with D, CO, THF, and PhCCD.

Lewis acid-base 1,2-addition reactions: synthesis of pyrylium borates from en-ynoate precursors.

Treatment of methyl (Z)-2-alken-4-ynoates with the strong Lewis acid tris(pentafluorophenyl) borane, B(C6F5)3, yield substituted zwitterionic pyrylium borate species via an intramolecular 6-endo-dig cyclisation reaction.

Influenza vaccinations and chemosensory function.

Background: Although influenza vaccines have saved millions of lives, some have been associated with extremely rare adverse effects such as Guillain-Barré syndrome, Bell's palsy, and optic neuritis. Despite the fact that olfactory loss after an influenza vaccination is noted in one case report, no quantitative olfactory testing was performed. Hence, it is unclear whether, in fact, olfactory dysfunction can be associated with such vaccinations.