White City is a small area in west london created as an exhibition site in 1908, morphing over the years into an Olympic games venue, a greyhound track, the home nearby of the BBC (British Broadcasting Corporation) and most recently the new western campus for Imperial College London.♣ The first Imperial department to move into the MSRH (Molecular Sciences Research Hub) building is chemistry. As a personal celebration of this occasion, I here dedicate three transition states located during my first week of occupancy there, naming them the White City trio following earlier inspiration by a string trio and their own instruments.
Archive for the ‘Interesting chemistry’ Category
A Theoretical Method for Distinguishing X‐H Bond Activation Mechanisms.
Wednesday, July 25th, 2018Consider the four reactions. The first two are taught in introductory organic chemistry as (a) a proton transfer, often abbreviated PT, from X to B (a base) and (b) a hydride transfer from X to A (an acid). The third example is taught as a hydrogen atom transfer or HAT from X to (in this example) O. Recently an article has appeared[cite]10.1002/anie.201805511[/cite] citing an example of a fourth fundamental type (d), which is given the acronym cPCET which I will expand later. Here I explore this last type a bit further, in the context that X-H bond activations are currently a very active area of research.
Chemistry (and music) in the Park.
Thursday, July 12th, 2018This last month, as a follow-up to the preceding post on the colour of flowers, I have been moonlighting by blogging elsewhere. Do go visit my “guerrilla blog” at perivalepark.london. Part of this project involves visiting two “physic or botanic” gardens, which originate from early 17th century explorations of herbs and other botanicals as medicines. Both are very old and their chemistry is indeed fascinating; more of which later.
Why do flowers such as roses, peonies, dahlias, delphiniums (etc), exhibit so many shades of colours?
Monday, June 18th, 2018It was about a year ago that I came across a profusion of colour in my local Park. Although colour in fact was the topic that sparked my interest in chemistry many years ago (the fantastic reds produced by diazocoupling reactions), I had never really tracked down the origin of colours in many flowers. It is of course a vast field. Here I take a look at just one class of molecule responsible for many flower colours, anthocyanidin, this being the sugar-free counterpart of the anthocyanins found in nature.
Examples please of FAIR (data); good and bad.
Sunday, May 6th, 2018The site fairsharing.org is a repository of information about FAIR (Findable, Accessible, Interoperable and Reusable) objects such as research data.
Aromaticity-induced basicity.
Wednesday, April 18th, 2018The molecules below were discussed in the previous post as examples of highly polar but formally neutral molecules, a property induced by aromatisation of up to three rings. Since e.g. compound 3 is known only in its protonated phenolic form, here I take a look at the basicity of the oxygen in these systems to see if deprotonation of the ionic phenol form to the neutral polar form is viable.
A record polarity for a neutral compound?
Friday, April 13th, 2018In several posts a year or so ago I considered various suggestions for the most polar neutral molecules, as measured by the dipole moment. A record had been claimed[cite]10.1002/anie.201508249[/cite] for a synthesized molecule of ~14.1±0.7D. I pushed this to a calculated 21.7D for an admittedly hypothetical and unsynthesized molecule. Here I propose a new family of compounds which have the potential to extend the dipole moment for a formally neutral molecule up still further.