In the pipeline reports on an intriguing new ring system acting as an isostere for morpholine. I was interested in how the conformation of this ring system might be rationalised electronically and so I delved into the article.[cite]10.1021/acs.jmedchem.9b00348[/cite] Here I recount what I found.
Archive for the ‘Interesting chemistry’ Category
A Non-nitrogen Containing Morpholine Isostere; an application of FAIR data principles.
Sunday, August 4th, 2019Anniversaries: The World-Wide-Web at 30 and 25 (+ CERN’s LHC as a bonus).
Saturday, June 15th, 2019
The World-Wide-Web is currently celebrating its 30th anniversary; you can get the T-shirt in the CERN visitor centre! Five years on, in May 1994, the first Web conference took place (WWW94) at CERN and now celebrating its own 25th anniversary. That 1994 conference also had various break-out sessions, one of which summarised the state of chemistry on the web at the time. You can see my general but entirely personal impressions written after the workshop (DOI: 10.14469/hpc/5850), with a chemistry specific version at DOI: 10.14469/hpc/5851. A real trip down memory lane and an indication of how much has happened in 25 years!
ChemRxiv. Why?
Wednesday, June 5th, 2019In August 2016, the launch of a chemistry pre-print service ChemRxiv was announced. I was phoned a day or so later by a staff journalist at C&E News for my opinion. The only comment that was retained for their report was my instantaneous feeling that “the community needed a chemistry pre-print server like one needed a hole in the head“. I had been there before you see, recollecting a pre-print server launched by the ChemWeb service around 1996 or 1997 and which lasted only about two years before being withdrawn due to the low quality of the preprints. So what do I think of ChemRxiv now in 2019?
Diatomics with eight valence-electrons: formation by radioactive decay.
Sunday, June 2nd, 2019This is a follow up to my earlier post about C⩸N+, itself inspired by this ChemRxiv pre-print[cite]10.26434/chemrxiv.8009633.v1[/cite] which describes a chemical synthesis of singlet biradicaloid C2 and its proposed identification as such by chemical trapping.
Startling bonds: revisiting C⩸N+, via the helium bond in N≡C-He+.
Monday, May 27th, 2019Although the small diatomic molecule known as dicarbon or C2 has been known for a long time, its properties and reactivity have really only been determined via its very high temperature generation. My interest started in 2010, when I speculatively proposed here that the related isoelectronic species C⩸N+ might sustain a quadruple bond. Shortly thereafter, a torrent of theoretical articles started to appear in which the idea of a quadruple bond to carbon was either supported or rejected. Clearly more experimental evidence was needed. The recent appearance of a Chemrxiv pre-print entitled “Room-temperature chemical synthesis of C2“.[cite]10.26434/chemrxiv.8009633.v1[/cite] claims to provide just this! Using the synthetic scheme outlined below, they trapped “C2” with a variety of reagents (see Figure 2A in their article), concluding that the observed reactivity best matched that of singlet “biradicaloid” C2 sustaining a quadruple bond.
The Graham reaction: Deciding upon a reasonable mechanism and curly arrow representation.
Monday, February 18th, 2019Students learning organic chemistry are often asked in examinations and tutorials to devise the mechanisms (as represented by curly arrows) for the core corpus of important reactions, with the purpose of learning skills that allow them to go on to improvise mechanisms for new reactions. A common question asked by students is how should such mechanisms be presented in an exam in order to gain full credit? Alternatively, is there a single correct mechanism for any given reaction? To which the lecturer or tutor will often respond that any reasonable mechanism will receive such credit. The implication is that a mechanism is “reasonable” if it “follows the rules”. The rules are rarely declared fully, but seem to be part of the absorbed but often mysterious skill acquired in learning the subject. These rules also include those governing how the curly arrows should be drawn.† Here I explore this topic using the Graham reaction.[cite]10.1021/ja00947a040[/cite]‡
The Chemistry of the Book of Kells
Tuesday, January 22nd, 2019The Book of Kells is a spectacularly illuminated gospel manuscript dating from around 800AD and held in Trinity College library in Dublin. Some idea of the colours achieved can be seen below.