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Henry Rzepa's Blog

Henry Rzepa's Blog
Chemistry with a twist
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Peter Murray-Rust and I are delighted to announce that the 2016 award of the Bradley-Mason prize for open chemistry goes to Jan Szopinski (UG) and Clyde Fare (PG). Jan’s open chemistry derives from a final year project looking at why atom charges derived from quantum chemical calculation of the electronic density represent chemical information well, but the electrostatic potential (ESP) generated from these charges is very

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The story so far. Imines react with a peracid to form either a nitrone (σ-nucleophile) or an oxaziridine (π-nucleophile).[cite]10.1016/S0040-4039(00)98582-4[/cite] The balance between the two is on an experimental knife-edge, being strongly influenced by substituents on the imine.

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Compounds with O-O bonds often have weird properties. For example, artemisinin, which has some fascinating stereoelectronics. Here is another such, recently in the news and known as HMTD (hexamethylene triperoxide diamine). The crystal structure was reported some time ago[cite]10.1021/jp0123841[/cite] and the article included an inspection of the computed wavefunction.

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Nucleophiles are species that seek to react with an electron deficient centre by donating a lone or a π-bond pair of electrons. The ambident variety has two or more such possible sources in the same molecule, an example of which might be hydroxylamine or H 2 NOH.

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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

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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.

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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.

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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.