About 18 months ago, there was much discussion on this blog about a system reported by Bob Pascal and co-workers containing a short H…H contact of ~1.5Å[cite]10.1021/ja407398w[/cite]. In this system, the hydrogens were both attached to Si as Si-H…H-Si and compressed together by rings.

My holiday reading has been Derek Lowe’s excellent Chemistry Book setting out 250 milestones in chemistry, organised by year. An entry for 1920 entitled hydrogen bonding seemed worth exploring in more detail here.

I previously used data mining of crystal structures to explore the directing influence of substituents on aromatic and heteroaromatic rings. Here I explore, quite literally, a different angle to the hydrogen bonding interactions between a benzene ring and OH or NH groups. I start by defining a benzene ring with a centroid.

Solvolytic mechanisms are amongst the oldest studied, but reproducing their characteristics using computational methods has been a challenging business.

I recently got an email from a student asking about the best way of rationalising epoxide ring opening using some form of molecule orbitals.

Curly arrows are something most students of chemistry meet fairly early on. They rapidly become hard-wired into the chemists brain. They are also uncontroversial! Or are they? Consider the following very simple scheme. Curly arrow pushing It represents protonation of an alkene by an acid.

One of the (not a few) pleasures of working in a university is the occasional opportunity that arises to give a new lecture course to students.