November 4th, 2018
For perhaps ten years now, the future of scientific publishing has been hotly debated. The traditional models are often thought to be badly broken, although convergence to a consensus of what a better model should be is not apparently close. But to my mind, much of this debate seems to miss one important point, how to publish data.
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Tags: Academia, Academic publishing, American Chemical Society, Angewandte Chemie, article processing charge, article processing charges, artificial intelligence, Cognition, Company: RSC, Electronic publishing, G factor, Hybrid open access journal, Knowledge, Michael Dewar, Nature, online era, Open access, Predatory publishing, Publishing, researcher, Royal Society of Chemistry, Scholarly communication, Science, Technology/Internet
Posted in Chemical IT | 2 Comments »
October 18th, 2018
The Royal Society of Chemistry historical group (of which I am a member) organises two or three one day meetings a year. Yesterday the October meeting covered (amongst other themes) the fascinating history of madder and its approximately synthetic equivalent alizarin. Here I add a little to the talk given by Alan Dronsfield on the synthesis of alizarin and the impact this had on the entire industry.
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Tags: Alan Dronsfield, Alizarin, Anthraquinone dyes, Art materials, BASF, Carl Graebe, Carl Gräbe, Carl Liebermann, Carl Theodore Liebermann, Catechols, Colors, cryoEM MicroEM, Dihydroxyanthraquinones, Dye, Mauve, Mauveine, Rapid structure determination of microcrystalline molecular compounds, Royal Society of Chemistry, Shades of violet, William Bragg, William Perkin
Posted in Historical | 1 Comment »
September 30th, 2018
Here is the concluding part of my exploration of a recently published laboratory experiment for undergraduate students.[cite]10.1021/acs.jchemed.7b00566[/cite] I had previously outlined a possible mechanistic route, identifying TS3 (below) as the first transition state in which C-C bond formation creates two chiral centres. This is followed by a lower energy TS4 where the final stereocentre is formed, accompanied by inversion of configuration of one of the previously formed centres (red below). Now I explore what transition state calculations have to say about the absolute configurations of the final stereocentres in the carbaldehyde product.
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Posted in Interesting chemistry | No Comments »
September 20th, 2018
Recently, the 100th anniversary of the birth of the famous chemist Derek Barton was celebrated with a symposium. One of the many wonderful talks presented was by Tobias Ritter and entitled “Late-stage fluorination for PET imaging” and this resonated for me. The challenge is how to produce C-F bonds under mild conditions quickly so that 18F-labelled substrates can be injected for the PET imaging. Ritter has several recent articles on this theme which you should read.[cite]10.1021/ja2048072[/cite],[cite]10.1021/acs.accounts.7b00413[/cite].
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Tags: Antimatter, Barton, Chemistry, Derek Barton, Fluorine, Medical physics, Medicinal radiochemistry, Natural sciences, Neuroimaging, Physical sciences, Positron emission tomography, Radiation therapy, Ritter, Tobias Ritter
Posted in Interesting chemistry | 9 Comments »
September 1st, 2018
I am exploring the fascinating diverse facets of a recently published laboratory experiment for undergraduate students.[cite]10.1021/acs.jchemed.7b00566[/cite] Previously I looked at a possible mechanistic route for the reaction between an enal (a conjugated aldehyde-alkene) and benzyl chloride catalysed by base and a chiral amine, followed by the use of NMR coupling constants to assign relative stereochemistries. Here I take a look at some chiroptical techniques which can be used to assign absolute stereochemistries (configurations).
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Tags: Absolute configuration, Biochemistry, bulk solutions, chemical transformations, Chemistry, Conformational isomerism, difficult energy difference, gas phase, higher energy forms, Isomer, Isomerism, Nature, Physical organic chemistry, Polarization, spectroscopy, stereochemical product, Stereochemistry, Stereoisomerism, Vibrational circular dichroism
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August 26th, 2018
In the previous post, I investigated the mechanism of cyclopropanation of an enal using a benzylic chloride using a quantum chemistry based procedure. Here I take a look at the NMR spectra of the resulting cyclopropane products, with an evaluation of the original stereochemical assignments.[cite]10.1021/acs.jchemed.7b00566[/cite]
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Tags: Benzyl group, Chemistry, Cyclopropanation, cyclopropane products, Cyclopropanes, Nuclear magnetic resonance, Organic chemistry, Organic reactions, Protecting groups
Posted in Interesting chemistry | No Comments »
August 25th, 2018
Symbiosis between computation and experiment is increasingly evident in pedagogic journals such as J. Chemical Education. Thus an example of original laboratory experiments[cite]10.1021/ed077p271[/cite],[cite]10.1021/ed078p1266[/cite] that later became twinned with a computational counterpart.[cite]10.1021/ed500398e[/cite] So when I spotted this recent lab experiment[cite]10.1021/acs.jchemed.7b00566[/cite] I felt another twinning approaching.
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Tags: Ammonium, Benzyl group, Cations, chemical diagrams, Chemistry, condensation, final product, Functional groups, Iminium, Methyl group, Name reactions, Organic chemistry, possible diastereomeric products, relative energy, Vector Graphics, web browsers
Posted in Interesting chemistry | 9 Comments »
August 22nd, 2018
Following the general recognition of carbon as being tetrahedrally tetravalent in 1869 (Paterno) and 1874 (Van’t Hoff and Le Bell), an early seminal exploitation of this to the conformation of cyclohexane was by Hermann Sachse in 1890.[cite]10.1002/cber.189002301216 [/cite] This was verified when the Braggs in 1913[cite]10.1098/rspa.1913.0084[/cite], followed by an oft-cited article by Mohr in 1918,[cite]10.1002/prac.19180980123[/cite] established the crystal structure of diamond as comprising repeating rings in the chair conformation.† So by 1926, you might imagine that the shape (or conformation as we would now call it) of cyclohexane would be well-known. No quite so for everyone!
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Tags: Carbon, chair, Chemistry, Conformation, Cycloalkanes, cyclohexane, Cyclohexane conformation, Derek Barton, Hermann Sachse, Hoff, Imperial College Chemical Society, Isomerism, Physical organic chemistry, R. F Hunter, Stereochemistry, Van 't Hof
Posted in Interesting chemistry | 1 Comment »
August 22nd, 2018
In 2012, I wrote a story of the first ever reaction curly arrows, attributed to Robert Robinson in 1924. At the time there was a great rivalry between him and another UK chemist, Christopher Ingold, with the latter also asserting his claim for their use. As part of the move to White City a lot of bookshelves were cleared out from the old buildings in South Kensington, with the result that yesterday a colleague brought me a slim volume they had found entitled The Journal of the Imperial College Chemical Society (Volume 6).‡
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Tags: arrow pushing, chemical reaction, Chemical Society, chemist, Chemistry, Christopher Ingold, Christopher Kelk Ingold, College of Science, Country: United Kingdom, Fellows of the Royal Society, Henry Armstrong, Imperial College Chemical Society, Imperial College London, Ingold, Knights Bachelor, Person Career, Robert Robinson, Royal College of Science, The Scientific Journal
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August 8th, 2018
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.
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Tags: acetic acid, Acid, Amide, Amine, carboxylic acid, Chemistry, Company: BBC, Company: British Broadcasting Corporation, energy, Ester, exhibition site, free energy barrier, Functional groups, Hydrogen bond, Imperial College, Imperial College London, Ionic product, Newspaper & Magazine Printing Services, Non-ionic product, Olympic games, Organic chemistry, White City Trio
Posted in Interesting chemistry | 6 Comments »