Another mechanistic study we started in 1972[cite]10.1039/P29770000281[/cite] is here 40+ years on subjected to quantum mechanical scrutiny.

The BBC TV quiz series Mastermind was first broadcast in the UK in 1972, the same time I was starting to investigate the mechanism of diazocoupling to substituted indoles as part of my Ph.D. researches. The BBC program became known for the catch phrase I've started so I'll finish; here I will try to follow this precept with the project I started then.

This question was posted on the CCL (computational chemistry list) by John McKelvey. Here, I give an answer in the form of a search of the CSD (crystal structure database). I was not sure if the question related purely to the geometries obtained using computational methods or to comparisons with experimentally determined structures. Or indeed whether it related to azobenzene specifically or to azobenzenes in general.

You might have noticed the occasional reference here to the upcoming centenary of the publication of Gilbert N. Lewis’ famous article entitled “ The atom and the molecule ”.[cite]10.1021/ja02261a002[/cite] A symposium exploring his scientific impact and legacy will be held in London on March 23, 2016, exactly 70 years to the day since his death. A list of the speakers and their titles is shown below;

The layout of floor 2 of the chemistry department here contains a number of small rooms which function as tutorial areas. Each has a (non-interactive) whiteboard used by students and tutors for, inter-alia , thought-showering. It was in one such room that I found myself with three colleagues this monday afternoon. We soon all sensed something not quite right about the room;

In answering tutorial problems, students often need skills in deciding how much time to spend on explaining what does not happen, as well as what does. Here I explore alternatives to the mechanism outlined in the previous post to see what computation has to say about what does (or might) not happen.

This reaction emerged a few years ago (thanks Alan!) as a tutorial problem in organic chemistry, in which students had to devise a mechanism for the reaction and use this to predict the stereochemical outcome at the two chiral centres indicated with *.  It originates in a brief report from R. B. Woodward’s group in 1973 describing a prostaglandin synthesis,[cite]10.1021/ja00801a066[/cite] the stereochemical outcome being crucial.

In the previous post, I pondered how a substituent (X below) might act to slow down the hydrolysis of an acetal. Here I extend that by probing the role of water molecules in the mechanism of acetal hydrolysis.

Derek Lowe has a recent post entitled " Another Funny-Looking Structure Comes Through ". He cites a recent medchem article[cite]10.1021/acsmedchemlett.5b00398[/cite] in which the following acetal sub-structure appears in a promising drug candidate (blue component below). His point is that orally taken drugs have to survive acid (green below) encountered in the stomach, and acetals are famously sensitive to hydrolysis (red below). But if

Steve Bachrach on his own blog has commented on a recent article[cite]10.1002/anie.201505934[/cite] discussing the structure of the trimer of fluoroethanol. Rather than the expected triangular form with three OH—O hydrogen bonds, the lowest energy form only had two such bonds, but it matched the microwave data much better. Here I explore this a bit more.

I have previously shown the grave of  William Perkin, a great british organic chemist. On a recent visit to  Paris, I went to see the crypt in the Panthéon, the great french secular necropolis. What a contrast to Perkin!  The Curies have a crypt all to themselves (VII), and other great french scientists such as Bertholet and Langevin as well as mathematicians such as Lagrange who are also interred in other crypts.