Posts Tagged ‘Country: United Kingdom’
Wednesday, 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).‡
This journal is a record of lectures given to the chemistry department by visiting speakers, this one dating from 1926, about two years after the article by Robinson noted above.
There are a number of points of interest.
- Early on, Ingold introduces the topic of atoms in combination. Lewis (who is acknowledged to have introduced this concept in 1916) is mentioned in parentheses, if not actually in passing, as generalizing (Lewis) from this case, … As was the practice at the time, referencing one’s sources was not always common, and you do not here get an actual citation for Lewis!
- Next comes the topic changes in molecular structure (which could be a synonym for reactions) and here you get this diagram
A modern version is shown below, scarcely different! 
- Whilst the first example has examples such as SN1 ionizations, the second is perhaps not as common as might be imagined. It would only work if atom C (assuming it to be carbon) was e.g. a carbene (with six valence electrons) converting to a vinyl carbanion (with eight). Although we may speculate that Ingold thought that the second example might relate to common reactions, in the event both curly arrows are still entirely valid by modern standards. There is no acknowledgement of Robinson’s 1924 effort.
- Ingold goes on to discuss substitution patterns in benzene derivatives, and the o/p or m-directing abilities of substituents. He concludes that the Dewar formula for benzene is the most satisfactory vehicle for expressing the theory that electrical disturbances readily reach the o- and p-position, whilst only a small second order effect can reach the m-position. Here I think we can conclude that this approach has not survived into modern thinking. Robinson in his 1924 arrows had of course striven to explain the apparent propensity of nitrosobenzene towards electrophilic substitution in the p-position. Henry Armstrong some thirty years earlier in 1887[1] had arguably already made a pretty decent start, without requiring the use of Dewar benzene.
I suspect those who have dug through the historical archives to cast light on the Robinson/Ingold rivalry may not have appreciated that the Journal of the Imperial College Chemical Society might have been an interesting source!
‡There were nine volumes produced during 1921-1930. It then morphed into The Scientific Journal of the Royal College of Science which continued for an unknown number of years.
References
- H.E. Armstrong, "XXVIII.—An explanation of the laws which govern substitution in the case of benzenoid compounds", J. Chem. Soc., Trans., vol. 51, pp. 258-268, 1887. https://doi.org/10.1039/ct8875100258
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
Posted in Interesting chemistry | No Comments »
Wednesday, 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).‡
This journal is a record of lectures given to the chemistry department by visiting speakers, this one dating from 1926, about two years after the article by Robinson noted above.
There are a number of points of interest.
- Early on, Ingold introduces the topic of atoms in combination. Lewis (who is acknowledged to have introduced this concept in 1916) is mentioned in parentheses, if not actually in passing, as generalizing (Lewis) from this case, … As was the practice at the time, referencing one’s sources was not always common, and you do not here get an actual citation for Lewis!
- Next comes the topic changes in molecular structure (which could be a synonym for reactions) and here you get this diagram
A modern version is shown below, scarcely different!
- Whilst the first example has examples such as SN1 ionizations, the second is perhaps not as common as might be imagined. It would only work if atom C (assuming it to be carbon) was e.g. a carbene (with six valence electrons) converting to a vinyl carbanion (with eight). Although we may speculate that Ingold thought that the second example might relate to common reactions, in the event both curly arrows are still entirely valid by modern standards. There is no acknowledgement of Robinson’s 1924 effort.
- Ingold goes on to discuss substitution patterns in benzene derivatives, and the o/p or m-directing abilities of substituents. He concludes that the Dewar formula for benzene is the most satisfactory vehicle for expressing the theory that electrical disturbances readily reach the o- and p-position, whilst only a small second order effect can reach the m-position. Here I think we can conclude that this approach has not survived into modern thinking. Robinson in his 1924 arrows had of course striven to explain the apparent propensity of nitrosobenzene towards electrophilic substitution in the p-position. Henry Armstrong some thirty years earlier in 1887[1] had arguably already made a pretty decent start, without requiring the use of Dewar benzene.
I suspect those who have dug through the historical archives to cast light on the Robinson/Ingold rivalry may not have appreciated that the Journal of the Imperial College Chemical Society might have been an interesting source!
‡There were nine volumes produced during 1921-1930. It then morphed into The Scientific Journal of the Royal College of Science which continued for an unknown number of years.
References
- H.E. Armstrong, "XXVIII.—An explanation of the laws which govern substitution in the case of benzenoid compounds", J. Chem. Soc., Trans., vol. 51, pp. 258-268, 1887. https://doi.org/10.1039/ct8875100258
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
Posted in Interesting chemistry | No Comments »
Friday, February 9th, 2018
Last year, I showed photos of wildflower meadows in west London close to where we live, evolving as the seasons changed. Today we hear the announcement that London itself is set be declared the world’s first National Park City in 2019.
What is a park city you may ask? It draws on the principles of National Parks such as the Peak District, the New Forest, or the South Downs in the UK, but in a city setting. It encourages people to explore how to improve life across the city, such as more time spent in nature outdoors and indeed visiting wild flower meadows! Meanwhile, spread the word.
As for those meadows, the “topping up” of last year’s seeding will start in March of 2018, and the area is set to expand substantially; it is pretty bare at the moment. When I get the list of expanded or new meadows, I will post here. Meanwhile I note that last year’s seeding of Cosmos produced a spectacular display which lasted at least three months. I cannot help but note that one of the main attractions at the RHS (Royal Horticultural Society) flower show at Chatsworth this year is the creation of a field of 12,000 Cosmos bipinnatus ‘Razzmatazz’, a river of flowers, outside the iconic Chatsworth House. This (IMHO) will be hard pressed to match that of west London last year!
Tags:City: London, Country: United Kingdom, Royal Horticultural Society, Wildflower
Posted in Interesting chemistry | 1 Comment »
Friday, February 10th, 2017
The book of the title has recently appeared giving a rich and detailed view over 417 pages, four appendices and 24 pages of photographs of how a university chemistry department in the UK came into being in 1845 and its subsequent history of discoveries, Nobel prizes and much more. If you have ever wondered what goes on in an academic department, populated by and large by very bright and clever personalities and occasionally some highly eccentric ones, then go dip into this book.
Here you will learn that starting in 1845, the department had 26 enrolled students, each paying a fee to attend lectures and to do experiments in the laboratories. You may observe the changes in laboratory practices over the years, and wonder how many of those early students survived their experiences and lived into old age. The book centres around the people in the department, with many anecdotes and stories about life in such a department, some of the stories about chemistry and some not! The chemistry these people discovered and recorded in journals can be quickly accessed using the (short) DOIs provided for many of the entries in the bibliography.
Few academic departments can have been documented in such detail. Indeed one must wonder whether the wealth of written material available to the authors, Hannah Gay and Bill Griffith, during this period will be matched by the much more evanescent electronic records that have become prevalent since. Email was introduced into the department around 1987 and I suspect almost all that record has now vanished permanently. I would not envy the task of anyone faced with updating this history from 2001-2050!
An aspect that is much harder to document is the daily routines of the undergraduate students. The book has a wealth of information about the practical laboratories and the instruments and apparatus found in the department, but a little less about the changing face of the lectures and associated written materials, the tutorials and problems classes and student’s own interactions with the professors, once the core (academic) activities and experiences of an undergraduate. Nowadays one may well find sessions on entrepreneurship instead of a problems class, or a flipped classroom replacing the lecture.
My own undergraduate stay in the department was from 1968-1971 and I might append some of those memories to this post in the future. If anyone reading this has their own evocative recollections of being a chemistry undergraduate, either at Imperial or elsewhere, can I invite you to share them here!
Tags:2001-2050, Alfred Nobel, Bill Griffith, Country: United Kingdom, Education, Entertainment/Culture, Hannah Gay, Nobel Prize
Posted in Historical | 6 Comments »
