In the news this week is a report of a molecule whose crystal lattice is capable of both storing and releasing large amounts of hydrogen gas at modest pressures and temperatures. Thus “NU-1501-Al” can absorb 14 weight% of hydrogen. To power a low-polluting car with a 500 km range, about 4-5 kg of hydrogen gas would be need to be stored and released safely.

A reaction can be thought of as molecular dancers performing moves. A choreographer is needed to organise the performance into the ballet that is a reaction mechanism. Here I explore another facet of the Michael addition of a nucleophile to a conjugated carbonyl compound.

In the previous post, I introduced three of a new generation of search engines specialising in the discovery of data. Data has some special features which make its properties slightly different from the conceptual (or natural language) searches we are used to performing for general information and so a search engine specifically for data is invariably going to reflect this.

Chemists have long been familiar with search engines that aspire to index a large proportion of the chemical literature.

In the previous post, I looked at the mechanism for 1,4-nucleophilic addition to an activated alkene (the Michael reaction). The model nucleophile was malonaldehyde after deprotonation and the model electrophile was acrolein (prop-2-enal), with the rate determining transition state being carbon-carbon bond formation between the two, accompanied by proton transfer to the oxygen of the acrolein.

In 2013, I created an iTunesU library of 115 mechanistic types in organic and organometallic chemistry, illustrated using video animations of the intrinsic reaction coordinate (IRC) computed using a high level quantum mechanical procedure. Many of those examples first derived from posts here. That collection  is still available and is viewable  in the iTunesU app on an iPhone or an iPad.

A PID or persistent identifier has been in common use in scientific publishing for around 20 years now. It was introduced as a DOI (Digital Object Identifier), and the digital object in this case was the journal article. From 2000 onwards, DOIs started appearing for most journal articles, journals having obtained them from a registration agency, CrossRef.

In 2001, Shaik and co-workers published the first of several famous review articles on the topic A Different Story of π-Delocalization.

In a welcome move, one of the American chemical society journals has published an encouragement to submit what is called FAIR data to the journal.[cite]10.1021/acs.orglett.0c00383[/cite]. A reminder that FAIR data is data that can be Found (F), Accessed (A), Interoperated(I) and Re-used( R). I thought I might try to explore this new tool here. You start at the ACS Research Data Center

Here is another selection from the Molecules-of-the-Year shortlist published by C&E News, in which hexagonal planar transition metal coordination is identified.

I noted in an earlier blog, a potential (if difficult) experimental test of the properties of the singlet state of dicarbon, C ₂ . Now, just a few days ago, a ChemRxiv article has been published suggesting another (probably much more realistic) test.[cite]10.26434/chemrxiv.11446224.v1[/cite] This looks at the so-called ⁷ Σ open shell state of the molecule where three electrons from one σ and two π orbitals are excited