Way back in 2010, I was writing about an experience I had just had during an organic chemistry tutorial, which morphed into speculation as to whether a carbon atom might sustain a quadruple bond to nitrogen. A decade on, and possibly approaching 100 articles by many authors on the topic, quadruple bonds to carbon continue to fascinate.

In Internet terms, 23 years ago is verging on pre-history. Much of what was happening around 1997 on the Web was still highly experimental and so its worth taking a look at some of this to see how it has survived or whether it can be “curated” into a form that would still be useful.

In an earlier post, I pondered on how the “arrow pushing” for the thermal pericyclic reactions of some annulenes (cyclic conjugated hydrocarbons) could be represented in terms of either two separate electrocyclic reactions or of one cycloaddition reaction.

The title of this post indicates the exciting prospect that a method of producing a room temperature superconductor has finally been achived[cite]10.1038/s41586-020-2801-z[/cite]. This is only possible at enormous pressures however; >267 gigaPascals (GPa) or 2,635,023 atmospheres.

I occasionally spot an old blog that emerges, if only briefly, as “trending”. In this instance, only the second blog I ever wrote here, way back in 2009 as a follow up to this article.[cite]10.1021/ed084p1535[/cite] With something of that age, its always worth revisiting to see if any aspect needs updating or expanding, given the uptick in interest.

With universities around the world having to very rapidly transition to blended learning (a mixture of virtual and face-2-face experiences) with a very large component based on online materials, I thought it might be interesting to try to give one snapshot of when the online experience started to happen in chemistry. My start point will in fact be 1993, when the method of exposing online content currently in use (the “web”) really got going.

These four posts (the box set) set out to try to define the energetics for a reasonable reaction path for the Willgerodt-Kindler reaction. The rate of this reaction corresponds approximately to a free energy barrier of ~30 kcal/mol. Any pathway found to be >10 kcal/mol at its highest point above this barrier was deemed less probable. The first three efforts at defining such pathways all gave such a result.

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.