I previously explored stabilized “carbenes” with the formal structures (R ₂ N) ₂ C:, concluding that perhaps the alternative ionic representation R ₂ N ⁺ =C ^– NR ₂ might reflect their structures better.

To quote from Wikipedia: in chemistry, a carbene is a molecule containing a neutral carbon atom with a valence of two and two unshared valence electrons . The most ubiquitous type of carbene of recent times is the one shown below as 1 , often referred to as a resonance stabilised or persistent carbene . This type is of interest because of its ability to act as a ligand to an astonishingly wide variety of

Bromoallene is a pretty simple molecule, with two non-equivalent double bonds. How might it react with an electrophile, say dimethyldioxirane (DMDO) to form an epoxide?[cite]10.1039/C6CC06395K[/cite] Here I explore the difference between two different and very simple approaches to predicting its reactivity. Both approaches rely on the properties of the reactant and use two types of molecule orbitals derived from its electronic wavefunction.

In the previous post, I noted that a chemistry publisher is about to repeat an earlier experiment in serving pre-prints of journal articles. It would be fair to suggest that following the first great period of journal innovation, the boom in rapid publication “camera-ready” articles in the 1960s, the next period of rapid innovation started around 1994 driven by the uptake of the World-Wide-Web.

This week the ACS announced its intention to establish a “ ChemRxiv preprint server to promote early research sharing ”. This was first tried quite a few years ago, following the example of especially the physicists. As I recollect the experiment lasted about a year, attracted few submissions and even fewer of high quality.

The previous post contained an exploration of the anomeric effect as it occurs at an atom centre X for which the effect is manifest in crystal structures.

In the last few posts, I have explored the anomeric effect as it occurs at an atom centre X. Here I try to summarise the atoms for which the effect is manifest in crystal structures.

Here is a little molecule that can be said to be pretty electron rich. There are lots of lone pairs present, and not a few electron-deficient σ-bonds. I thought it might be fun to look at the stereoelectronic interactions set up in this little system.

In March, I posted from the ACS meeting in San Diego on the topic of Research data: Managing spectroscopy-NMR, and noted a talk by MestreLab Research on how a tool called Mpublish in the forthcoming release of their NMR analysis software Mestrenova could help. With that release now out, the opportunity arose to test the system.

The previous post looked at anomeric effects set up on centres such as B, Si or P, and involving two oxygen groups attached to these atoms.

The anomeric effect occurs at 4-coordinate (sp ³ ) carbon centres carrying two oxygen substituents and involves an alignment of a lone electron pair on one oxygen with the adjacent C-O σ*-bond of the other oxygen. Here I explore whether other centres can exhibit the phenomenon.