In 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.

This 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 C ₂ and its proposed identification as such by chemical trapping.

Although the small diatomic molecule known as dicarbon or C ₂ 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.

Ken Houk’s group has recently published this study of cycloaddition reactions, using a combination of classical transition state location followed by molecular dynamics trajectory calculations,[cite]10.1021/jacs.8b12674[/cite] and to which Steve Bachrach’s blog alerted me. The reaction struck me as being quite polar (with cyano groups) and so I took a look at the article to see what both the original[cite]10.1021/jo00042a039[/cite] experimental

Previously, I explored (computationally) the normal vibrational modes of Co(II)-tetraphenylporphyrin (CoTPP) as a “flattened” species on copper or gold surfaces for comparison with those recently imaged[cite]10.1038/s41586-019-1059-9[/cite]. The initial intent was to estimate the “flattening” energy. There are six electronic possibilities for this molecule on a metal surface.

In a previous post, I looked at the Findability of FAIR data in common chemistry journals. Here I move on to the next letter, the A = Accessible. The attributes of A[cite]10.1038/sdata.2016.18[/cite] include: (meta)data are retrievable by their identifier using a standardized communication protocol. the protocol is open, free and universally implementable.  the protocol allows for an authentication and authorization procedure.

The topic of this post originates from a recent article which is attracting much attention.[cite]10.1038/s41586-019-1059-9[/cite] The technique uses confined light to both increase the spatial resolution by around three orders of magnitude and also to amplify the signal from individual molecules to the point it can be recorded. To me, Figure 3 in this article summarises it nicely (caption: visualization of vibrational normal modes ).

In recent years, findable data has become ever more important (the F in FAIR). Here I test that F using the DataCite search service. Firstly an introduction to this service. This is a metadata database about datasets and other research objects.

The conventional procedures for reporting analysis or new results in science is to compose an “article”, augment that perhaps with “supporting information” or “SI”, submit to a journal which undertakes peer review, with revision as necessary for acceptance and finally publication. If errors in the original are later identified, a separate corrigendum can be submitted to the same journal, although this is relatively rare.

Previously, I explored the Graham reaction to form a diazirine. The second phase of the reaction involved an Sn2′ displacement of N-Cl forming C-Cl. Here I ask how facile the simpler displacement of C-Cl by another chlorine might be and whether the mechanism is Sn2 or the alternative Sn1.