I have variously talked about persistent identifiers on this blog. These largely take the form of DOIs (Digital object identifiers), and here they relate to either journal articles or datasets associated with either the article or the blog post or both. Other disciplines, particularly the earth sciences, have long used persistent identifiers (PIDs) to identify physical objects rather than digital ones.

Sometimes, the properties of a molecule are predicted long before it is synthesised. One such is diberyllocene. I first encountered a related molecule, beryllocene itself, many moons ago.[cite]10.1021/ja00471a020[/cite] This was unusual because unlike the original metallocenes, the metal atom was not symmetrically disposed between the two cyclopentadienyl faces.

This is a venerable organic reaction, which curiously I have not previously covered here. First described in 1859, its nature was only properly elucidated in 1873. It is a member of a class of reaction I have previously named “solvolytically assisted pericyclic”, or “perisolvolytic”. Here I explore some of the subtle stereoelectronic effects observed for this apparently simple reaction. It applies to a class of molecule known as 1,2-diols.

This editorial from Nature[cite]10.1038/d41586-023-01612-x[/cite] is a timely reminder of the importance of data.

Some time ago in 2010, I showed a chemical problem I used to set during university entrance interviews. It was all about pattern recognition and how one can develop a hypothesis based on this. In that instance, it involved recognising that a cyclic molecule which appeared to have the cyclohexatriene benzene-aromatic pattern 1 was in fact a trimer of carbon dioxide.

One of the important aspects of chemical reaction mechanisms is the order in which things happen. More specifically, the order in which bonds make or break when there are more than two involved in undertaking a reaction.

Science frequently works by people making connections between related (or even apparently unrelated) concepts or data. There are many ways of helping people make these connections – attending a conference or seminar, searching journals for published articles and nowadays also searching for data are just a few examples.

Nature has produced most natural molecules as chiral objects, which means the molecule can come in two enantiomeric forms, each being the mirror image of the other. When a natural product is synthesised in a laboratory, a chiral synthesis means just one form is made, and then is compared with the natural product to see if it matches.

I have previously looked at the pigments used to colour the Book of Kells, which dates from around 800 AD and which contained arsenic sulfide as the yellow colourant. The Bayeaux tapestry is a later embroidery dating probably from around 1077 and here the colours are based entirely on mordanted natural dyes.

In the previous post, I discussed how data associated with two of the candidates for molecules of the year – 2022 could be retrieved and then used to inspect their three dimensional structures.

The list of molecules of the year is out now at C&E News (but you have to have an account to view the list, unlike previous years). ^♣ These three caught my eye: Electron in a cube: Synthesis and characterization of perfluorocubane as an electron acceptor ,[cite]10.1126/science.abq0516[/cite]. I have already written about this system and will not discuss it further, except to note this one topped the poll!