Having shown that carbon as a carbene centre, C : can act as a hydrogen bond acceptor, as seen from a search of crystal structures, I began to wonder if there is any chance that carbon as a radical centre, C• could do so as well. Definitely a subversive thought, since radical centres are supposed to abstract hydrogens rather than to hydrogen bond to them.

I have previously looked at the topic of hydrogen bonding interactions from the hydrogen of chloroform Here I generalize C-H…O interactions by conducting searches of the CSD (Cambridge structure database) as a function of the carbon hybridisation. I am going to jump straight to a specific molecule XEVJIR (DOI: 10.5517/cc5fgpq) identified from the searches appended to this post as interesting for further

There is a predilection amongst chemists for collecting records; one common theme is the length of particular bonds, either the shortest or the longest.

C&EN has again run a vote for the 2017 Molecules of the year. Here I take a look not just at these molecules, but at how FAIR (Findable, Accessible, Interoperable and Reusable) the data associated with these molecules actually is. I went about finding out as follows: The article DOI for all seven candidates was linked to the C&EN site.

FAIR data is increasingly accepted as a description of what research data should aspire to; F indable, A ccessible, I nter-operable and R e-usable, with Context added by rich metadata (and also that it should be Open). But there are two sides to data, one of which is the raw data emerging from say an instrument or software simulations and the other in which some

An N-B single bond is iso-electronic to a C-C single bond, as per below. So here is a simple question: what form does the distribution of the lengths of these two bonds take, as obtained from crystal structures?  The Conquest search query is very simple (no disorder, no errors). When applied to the Cambridge structure database (CSD) the following two distributions are obtained.

In the previous post, I noted the crystallographic detection of an unusually short non-bonded H…H contact of ~1.5Å, some 0.9Å shorter than twice the van der Waals radius of hydrogen (1.2Å, although some sources quote 1.1Å which would make the contraction ~0.7Å). This was attributed to dispersion attractions accumulating in the rest of the molecule.

The iron complex shown below forms the basis for many catalysts.[cite]10.1002/anie.200502985[/cite] With iron, the catalytic behaviour very much depends on the spin-state of the molecule, which for the below can be either high (hextet) or medium (quartet) spin, with a possibility also of a low spin (doublet) state. Here I explore whether structural information in crystal structures can reflect such spin states.

Conformational polymorphism occurs when a compound crystallises in two polymorphs differing only in the relative orientations of flexible groups ( e.g. Ritonavir).[cite]10.1039/D1SC06074K[/cite] At the Beilstein conference, Ian Bruno mentioned another type; tautomeric polymorphism , where a compound can crystallise in two forms differing in the position of acidic protons. Here I explore three such examples.

Derek Lowe highlights a recent article[cite]10.1002/anie.201702626[/cite] postulating CH⋅⋅⋅π interactions in proteins. Here I report a quick check using the small molecule crystal structure database (CSD). The search query (DOI: 10.14469/hpc/2594) is shown below.