Here I investigate a recent report[cite]10.1126/sciadv.abc0495[/cite] of a new generation of polyesters with the intrinsic properties of high crystallinity and chemical recyclability. The latter point is key, since many current plastics cannot be easily recycled to a form which can be used to regenerate the original polymer with high yield. Here I show some aspects of this fascinating new type of polymer.

The folks at DataCite have announced a new research object discovery service which aims to give users a “*comprehensive overview of connections between entities in the research landscape”*. The portal https://commons.datacite.org acts as the entry point for three basic types of persistent identifiers (PIDs); Research works, using the DOI (digital object identifier) as a PID.

The two previous surveys of the potential energy surface for this, it has to be said, rather obscure reaction led to energy barriers that were rather to high to be entirely convincing. So here is a third possibility. The red section corresponds to the previous exploration, in which a 3-membered sulfur ring intermediate was mooted. Here we go back to a 3-ring with nitrogen instead.

Continuing an exploration of the mechanism of this reaction, an alternative new mechanism was suggested in 1989 (having been first submitted to the journal ten years earlier!).[cite]10.1002/jhet.5570260518[/cite] Here the key intermediate proposed is a thiirenium cation (labelled 8 in the article) and labelled Int3 below.

Sometimes a (scientific) thought just pops into one’s mind. Most are probably best not shared with anyone, but since its the summer silly season, I thought I might with this one. Famously, according to Einstein, m  = E/c^^2, the equivalence of energy to mass. Consider a typical exoenergic chemical reaction:  A → B, ΔG -100 kJ/mol.

The Willgerodt reaction[cite]10.1002/cber.18870200278[/cite], discovered in 1887 and shown below, represents a transformation with a once famously obscure mechanism. A major step in the elucidation of that mechanism came[cite]10.1021/ja01157a034[/cite] using the then new technique of ¹⁴ C radio-labelling, shortly after the atom bomb projects during WWII made ¹⁴ CO ₂ readily available to researchers.

One of the most fascinating and important articles dealing with curly arrows I have seen is that by Klein and Knizia on the topic of C-H bond activations using an iron catalyst.[cite]10.1002/anie.201805511[/cite] These are so-called high spin systems with unpaired electrons and the mechanism of C-H activation involves both double headed (two electron) and fish-hook (single electron) movement.

Metaldehyde is an insecticide used to control slugs.

With the current global lockdown, and students along with everyone else staying at home, I have noticed some old posts of mine are getting more attention than normal.

My previous two posts on the topic of strongest bonds have involved mono and diprotonating N ₂ and using quantum mechanics to predict the effect this has on the N-N bond via its length and vibrational stetching mode. Such species are very unlikely to be easily observed for verification.