Sir Christopher Kelk Ingold (28 October 1893 – 8 December 1970) was a British

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of ...

based in Leeds and London. His groundbreaking work in the 1920s and 1930s on reaction mechanisms and the electronic structure of organic compounds was responsible for the introduction into mainstream chemistry of concepts such as

nucleophile In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are ...

electrophile In chemistry, an electrophile is a chemical species that forms bonds with nucleophiles by accepting an electron pair. Because electrophiles accept electrons, they are Lewis acids. Most electrophiles are positively Electric charge, charged, have an ...

, inductive and resonance effects, and such descriptors as S_N1, S_N2, E1, and E2. He also was a co-author of the Cahn–Ingold–Prelog priority rules. Ingold is regarded as one of the chief pioneers of

physical organic chemistry Physical organic chemistry, a term coined by Louis Hammett in 1940, refers to a discipline of organic chemistry that focuses on the relationship between chemical structures and chemical reaction, reactivity, in particular, applying experimental to ...

Early life and education

Born in London to a silk merchant who died of tuberculosis when Ingold was five years old, Ingold began his scientific studies at Hartley University College at Southampton (now Southampton University) taking an external BSc in 1913 with the

University of London The University of London (UoL; abbreviated as Lond or more rarely Londin in Post-nominal letters, post-nominals) is a collegiate university, federal Public university, public research university located in London, England, United Kingdom. The ...

. He then joined the laboratory of Jocelyn Field Thorpe at Imperial College, London, with a brief hiatus from 1918–1920 during which he conducted research into chemical warfare and the manufacture of poison gas with Cassel Chemical at

Glasgow Glasgow is the Cities of Scotland, most populous city in Scotland, located on the banks of the River Clyde in Strathclyde, west central Scotland. It is the List of cities in the United Kingdom, third-most-populous city in the United Kingdom ...

. Ingold received an MSc from the University of London and returned to Imperial College in 1920 to work with Thorpe. He was awarded a PhD in 1918 and a DSc in 1921.

Academic career

In 1924 Ingold moved to the

University of Leeds The University of Leeds is a public research university in Leeds, West Yorkshire, England. It was established in 1874 as the Yorkshire College of Science. In 1884, it merged with the Leeds School of Medicine (established 1831) and was renamed Y ...

where he spent six years as

Professor Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other tertiary education, post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin ...

Organic Chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic matter, organic materials, i.e., matter in its various forms that contain ...

working alongside his wife, Dr. Edith Hilda Ingold (Usherwood). He returned to London in 1930, and served for 24 years as head of the chemistry department at

University College London University College London (Trade name, branded as UCL) is a Public university, public research university in London, England. It is a Member institutions of the University of London, member institution of the Federal university, federal Uni ...

, from 1937 until his retirement in 1961. During his study of alkyl halides, Ingold found evidence for two possible reaction mechanisms for nucleophilic substitution reactions. He found that tertiary alkyl halides underwent a two-step mechanism (S_N1) while primary and secondary alkyl halides underwent a one-step mechanism (S_N2). This conclusion was based on the finding that reactions of tertiary alkyl halides with nucleophiles were dependent on the concentration of the alkyl halide only. Meanwhile, he discovered that primary and secondary alkyl halides, when reacting with nucleophiles, depend on both the concentration of the alkyl halide and the concentration of the nucleophile. Starting around 1926, Ingold and Robert Robinson carried out a heated debate on the electronic theoretical approaches to organic reaction mechanisms. See, for example, the summary by Saltzman. Ingold authored and co-authored 443 papers. Notable students include Peter de la Mare, Ronald Gillespie and Ronald Nyholm.

Honours

In 1920, Ingold was awarded the British Empire Medal (BEM) for his wartime research involving "great courage in carrying out work in a poisonous atmosphere, and risking his life on several occasions in preventing serious accidents," though he subsequently never discussed the award or this period in his life. Ingold was elected a Fellow of the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

(FRS) in 1924. He received the Longstaff Medal of the

Royal Society of Chemistry The Royal Society of Chemistry (RSC) is a learned society and professional association in the United Kingdom with the goal of "advancing the chemistry, chemical sciences". It was formed in 1980 from the amalgamation of the Chemical Society, the ...

in 1951, the Royal Medal of the

in 1952, and was knighted in 1958. The chemistry department of University College London is now housed in the Sir Christopher Ingold building, opened in 1969.

Personal life

Ingold married Dr. Edith Hilda Ingold (Usherwood) in 1923. She was a fellow chemist with whom he collaborated. They had two daughters and a son, the chemist Keith Ingold.

Death

Ingold died in London in 1970, aged 77.

References

External links

Biography at Michigan State University
an

at University College London. {{DEFAULTSORT:Ingold, Christopher Kelk British organic chemists Academics of the University of Leeds Academics of University College London Knights Bachelor Recipients of the British Empire Medal Royal Medal winners Fellows of the Royal Society 1893 births 1970 deaths Alumni of the University of Southampton Alumni of Imperial College London Stereochemists People from Edgware