Herbert C. Brown

Last updated
Herbert C. Brown
Herbert C. Brown.png
Born
Herbert Brovarnik

May 22, 1912
DiedDecember 19, 2004(2004-12-19) (aged 92)
NationalityAmerican
Alma mater University of Chicago
Known for Organoboranes
Spouse(s)Sarah Baylen (1937–2004; his death; 1 child)
Awards National Medal of Science (1969)
Elliott Cresson Medal (1978)
Nobel Prize for Chemistry (1979)
Priestley Medal (1981)
Perkin Medal (1982) [1]
AIC Gold Medal (1985)
NAS Award in Chemical Sciences (1987)
Scientific career
Fields Chemistry
Institutions University of Chicago,
Purdue University
Doctoral advisor Hermann Irving Schlesinger
Influenced Akira Suzuki
Ei-ichi Negishi

Herbert Charles Brown (May 22, 1912 – December 19, 2004) was an English-born American chemist and recipient of the 1979 Nobel Prize in Chemistry for his work with organoboranes.

Nobel Prize in Chemistry One of the five Nobel Prizes established in 1895 by Alfred Nobel

The Nobel Prize in Chemistry is awarded annually by the Royal Swedish Academy of Sciences to scientists in the various fields of chemistry. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895, awarded for outstanding contributions in chemistry, physics, literature, peace, and physiology or medicine. This award is administered by the Nobel Foundation, and awarded by Royal Swedish Academy of Sciences on proposal of the Nobel Committee for Chemistry which consists of five members elected by Academy. The award is presented in Stockholm at an annual ceremony on December 10, the anniversary of Nobel's death.

Contents

Life and career

Brown was born Herbert Brovarnik in London, to Ukrainian Jewish immigrants from Zhitomir, Pearl ( née Gorinstein) and Charles Brovarnik, a hardware store manager and carpenter. [2] His family moved to Chicago in June 1914, when he was two years old. [3] [4] Brown attended Crane Junior College in Chicago, where he met Sarah Baylen, whom he would later marry. The college was under threat of closing, and Brown and Baylen transferred to Wright Junior College. [4] In 1935 he left Wright Junior College and that autumn entered the University of Chicago, completed two years of studies in three quarters, and earned a B.S. in 1936. [3] That same year, he became a naturalized United States citizen. [5] On February 6, 1937, Brown married Baylen, the person he credits with making him interested in hydrides of boron, a topic related to the work in which he, together with Georg Wittig, won the Nobel prize in Chemistry in 1979. [3] Two years after starting graduate studies, he earned a Ph.D. in 1938, also from the University of Chicago.

London Capital of the United Kingdom

London is the capital and largest city of both England and the United Kingdom. Standing on the River Thames in the south-east of England, at the head of its 50-mile (80 km) estuary leading to the North Sea, London has been a major settlement for two millennia. Londinium was founded by the Romans. The City of London, London's ancient core − an area of just 1.12 square miles (2.9 km2) and colloquially known as the Square Mile − retains boundaries that follow closely its medieval limits. The City of Westminster is also an Inner London borough holding city status. Greater London is governed by the Mayor of London and the London Assembly.

Chicago City in Illinois, United States

Chicago, officially the City of Chicago, is the most populous city in Illinois, as well as the third most populous city in the United States. With an estimated population of 2,716,450 (2017), it is the most populous city in the Midwest. Chicago is the principal city of the Chicago metropolitan area, often referred to as Chicagoland, and the county seat of Cook County, the second most populous county in the United States. The metropolitan area, at nearly 10 million people, is the third-largest in the United States, and the fourth largest in North America and the third largest metropolitan area in the world by land area.

Wilbur Wright College, formerly known as Wright Junior College, is a public community college in Chicago. Part of the City Colleges of Chicago system, it offers 2-year associate's degrees, as well as occupational training in IT, manufacturing, medical, and business fields. Its main campus is located on Chicago's Northwest Side in the Dunning neighborhood.

Unable to find a position in industry, he decided to accept a postdoctoral position. This became the beginning of his academic career. He became an instructor at the University of Chicago in 1939, and held the position for four years before moving to Wayne University in Detroit as an assistant professor. In 1946, he was promoted to associate professor. He became a professor of inorganic chemistry at Purdue University in 1947 [6] and joined the Beta Nu Chapter of Alpha Chi Sigma there in 1960. [7] He held the position of Professor Emeritus from 1978 until his death in 2004. [3] The Herbert C. Brown Laboratory of Chemistry was named after him on Purdue University's campus. He was an honorary member of the International Academy of Science.

Professor academic rank at universities and other post-secondary education and research institutions in most countries

Professor is an academic rank at universities and other post-secondary education and research institutions in most countries. Literally, professor derives from Latin as a "person who professes" being usually an expert in arts or sciences, a teacher of the highest rank.

Inorganic chemistry deals with the synthesis and behavior of inorganic and organometallic compounds. This field covers all chemical compounds except the myriad organic compounds, which are the subjects of organic chemistry. The distinction between the two disciplines is far from absolute, as there is much overlap in the subdiscipline of organometallic chemistry. It has applications in every aspect of the chemical industry, including catalysis, materials science, pigments, surfactants, coatings, medications, fuels, and agriculture.

Purdue University public research university in West Lafayette, Indiana, United States

Purdue University is a public research university in West Lafayette, Indiana, and the flagship campus of the Purdue University system. The university was founded in 1869 after Lafayette businessman John Purdue donated land and money to establish a college of science, technology, and agriculture in his name. The first classes were held on September 16, 1874, with six instructors and 39 students.

During World War II, while working with Hermann Irving Schlesinger, Brown discovered a method for producing sodium borohydride (NaBH4), which can be used to produce boranes, compounds of boron and hydrogen. His work led to the discovery of the first general method for producing asymmetric pure enantiomers. The elements found as initials of his name H, C and B were his working field.

World War II 1939–1945 global war

World War II, also known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from over 30 countries. The major participants threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, marked by 50 to 85 million fatalities, most of whom were civilians in the Soviet Union and China. It included massacres, the genocide of the Holocaust, strategic bombing, premeditated death from starvation and disease, and the only use of nuclear weapons in war.

Hermann Irving Schlesinger was an American inorganic chemist, working in boron chemistry.

Sodium borohydride chemical compound

Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, is an inorganic compound with the formula NaBH4. This white solid, usually encountered as a powder, is a reducing agent that finds application in chemistry, both in the laboratory and on a technical scale. It has been tested as pretreatment for pulping of wood, but is too costly to be commercialized. The compound is soluble in alcohols, certain ethers, and even water, although it slowly hydrolyzes

In 1969, he was awarded the National Medal of Science. [8]

National Medal of Science award

The National Medal of Science is an honor bestowed by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral and social sciences, biology, chemistry, engineering, mathematics and physics. The twelve member presidential Committee on the National Medal of Science is responsible for selecting award recipients and is administered by the National Science Foundation (NSF).

Brown was quick to credit his wife Sarah with supporting him and allowing him to focus on creative efforts by handling finances, maintaining the house and yard, etc. According to Brown, after receiving the Nobel prize in Stockholm, he carried the medal and she carried the US$100,000 award.

Stockholm Capital city in Södermanland and Uppland, Sweden

Stockholm is the capital of Sweden and the most populous urban area in the Nordic countries; 962,154 people live in the municipality, approximately 1.5 million in the urban area, and 2.3 million in the metropolitan area. The city stretches across fourteen islands where Lake Mälaren flows into the Baltic Sea. Just outside the city and along the coast is the island chain of the Stockholm archipelago. The area has been settled since the Stone Age, in the 6th millennium BC, and was founded as a city in 1252 by Swedish statesman Birger Jarl. It is also the capital of Stockholm County.

He was inducted into the Alpha Chi Sigma Hall of Fame in 2000. [9]

He died December 19, 2004, at a hospital in Lafayette, Indiana after a heart attack. His wife died May 29, 2005, aged 89.

Research

Borane, BH3, is a gaseous compound that is only present at high temperatures. It dimerises to form diborane, B2H6. Diborane has a pair of three-center two-electron bonds. Borane & Diborane.jpg
Borane, BH3, is a gaseous compound that is only present at high temperatures. It dimerises to form diborane, B2H6. Diborane has a pair of three-center two-electron bonds.

As a doctoral student at the University of Chicago, Herbert Brown studied the reactions of diborane, B2H6. Hermann Irving Schlesinger's laboratory at the University of Chicago was one of two laboratories that prepared diborane. It was a rare compound that was only prepared in small quantities. Schlesinger was researching the reactions of diborane to understand why the simplest hydrogen-boron compound is B2H6 instead of BH3. [10]

A general reaction between diborane and a ketone Ketone diborane reduction.png
A general reaction between diborane and a ketone

When Brown started his own research, he observed the reactions of diborane with aldehydes, ketones, esters, and acid chlorides. He discovered that diborane reacts with aldehydes and ketones to produce dialkoxyboranes, which are hydrolyzed by water to produce alcohols. Until this point, organic chemists did not have an acceptable method of reducing carbonyls under mild conditions. Yet Brown's Ph.D. thesis published in 1939 received little interest. Diborane was too rare to be useful as a synthetic reagent. [10]

In 1939, Brown became the research assistant in Schlesinger's laboratory. In 1940, they began to research volatile, low molecular weight uranium compounds for the National Defense Research Committee. Brown and Schlesinger successfully synthesized volatile uranium(IV) borohydride, which had a molecular weight of 298. The laboratory was asked to provide a large amount of the product for testing, but diborane was in short supply. They discovered that it could be formed by reacting lithium hydride with boron trifluoride in ethyl ether, allowing them to produce the chemical in larger quantities. This success was met with several new problems. Lithium hydride was also in short supply, so Brown and Schlesinger needed to find a procedure that would allow them to use sodium hydride instead. They discovered that sodium hydride and methyl borate reacted to produce sodium trimethoxyborohydride, which was viable as a substitute for the lithium hydride. [10]

Soon they were informed that there was no longer a need for uranium borohydride, but it appeared that sodium borohydride could be useful in generating hydrogen. They began to look for a cheaper synthesis and discovered that adding methyl borate to sodium hydride at 250° produced sodium borohydride and sodium methoxide. When acetone was used in an attempt to separate the two products, it was discovered that sodium borohydride reduced the acetone. [10]

Sodium borohydride is a mild reducing agent that works well in reducing aldehydes, ketones, and acid chlorides. Lithium aluminum hydride is a much more powerful reducing agent that can reduce almost any functional group. When Brown moved to Purdue University in 1947, he worked to find stronger borohydrides and milder aluminum hydrides that would provide a spectrum of reducing agents. The team of researchers at Purdue discovered that changing the metal ion of the borohydride to lithium, magnesium, or aluminum increases the reducing ability. They also found that introducing alkoxy substituents to the aluminum hydride decreases the reducing ability. They successfully developed a full spectrum of reducing agents. [10]

In hydroboration-oxidation, the OH group adds to the less-substituted carbon in the double bond. Hydroboration-Oxidation.jpg
In hydroboration-oxidation, the OH group adds to the less-substituted carbon in the double bond.

While researching these reducing agents, Brown's coworker, Dr. B. C. Subba Rao, discovered an unusual reaction between sodium borohydride and ethyl oleate. The borohydride added hydrogen and boron to the carbon-carbon double bond in the ethyl oleate. The organoborane product could then be oxidized to form an alcohol. [10] This two-step reaction is now called hydroboration-oxidation and is a reaction that converts alkenes into anti-Markovnikov alcohols. Markovnikov's rule states that, in adding hydrogen and a halide or hydroxyl group to a carbon-carbon double bond, the hydrogen is added to the less-substituted carbon of the bond and the hydroxyl or halide group is added to the more-substituted carbon of the bond. In hydroboration-oxidation, the opposite addition occurs. [11]

See also

Related Research Articles

In chemistry, a hydride is the anion of hydrogen, H, or, more commonly, it is a compound in which one or more hydrogen centres have nucleophilic, reducing, or basic properties in it. In compounds that are regarded as hydrides, the hydrogen atom is bonded to a more electropositive element or groups. Compounds containing hydrogen bonded to metals or metalloid may also be referred to as hydrides. Common examples are ammonia (NH3), methane (CH4), ethane (C2H6) (or any other hydrocarbon), and Nickel hydride (NiH), used in NiMH rechargeable batteries.

Boranes any chemical compound composed of boron and hydrogen atoms only

Boranes is the name given to the class of synthetic hydrides of boron with generic formula BxHy. In the past, borane molecules were often labeled " electron-deficient" because of their multicenter bonding (in which a pair of bonding electrons links more than two atoms, as in 3-center-2-electron bonds); this was done in order to distinguish such molecules from hydrocarbons and other classically bonded compounds. However, this usage is incorrect, as most boranes and related clusters such as carboranes are actually electron-precise, not electron-deficient. For example, the extremely stable icosahedral B12H122- dianion, whose 26 cluster valence electrons exactly fill the 13 bonding molecular orbitals, is in no actual sense deficient in electrons; indeed it is thermodynamically far more stable than benzene.

In organic chemistry, the hydroboration–oxidation reaction is a two-step hydration reaction that converts an alkene into an alcohol. The process results in the syn addition of a hydrogen and a hydroxyl group where the double bond had been. Hydroboration–oxidation is an anti-Markovnikov reaction, with the hydroxyl group attaching to the less-substituted carbon. The reaction thus provides a more stereospecific and complementary regiochemical alternative to other hydration reactions such as acid-catalyzed addition and the oxymercuration–reduction process. The reaction was first reported by Herbert C. Brown in the late 1950s and it was recognized in his receiving the Nobel Prize in Chemistry in 1979.

Diborane chemical compound

Diborane(6), generally known as diborane is the chemical compound consisting of boron and hydrogen with the formula B2H6. It is a colorless, pyrophoric gas with a repulsively sweet odor. Synonyms include boroethane, boron hydride, and diboron hexahydride. Diborane is a key boron compound with a variety of applications. It has attracted wide attention for its electronic structure. Its derivatives are useful reagents.

Lithium aluminium hydride, commonly abbreviated to LAH, is an inorganic compound with the chemical formula LiAlH4. It was discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic synthesis, especially for the reduction of esters, carboxylic acids, and amides. The solid is dangerously reactive toward water, releasing gaseous hydrogen (H2). Some related derivatives have been discussed for hydrogen storage.

Organoboron chemistry

Organoborane or organoboron compounds are chemical compounds of boron and carbon that are organic derivatives of BH3, for example trialkyl boranes. Organoboron chemistry or organoborane chemistry is the chemistry of these compounds. Organoboron compounds are important reagents in organic chemistry enabling many chemical transformations, the most important one called hydroboration.

In chemistry, hydroboration refers to the addition of a hydrogen-boron bond to C-C, C-N, and C-O double bonds, as well as C-C triple bonds. This chemical reaction is useful in the organic synthesis of organic compounds. The development of this technology and the underlying concepts were recognized by the Nobel Prize in Chemistry to Herbert C. Brown. He shared the Nobel prize in chemistry with Georg Wittig in 1979 for his pioneering research on organoboranes as important synthetic intermediates.

Borohydride any chemical compound having a borohydride anion

Borohydride refers to the anion BH
4
and its salts. Borohydride is also the term used for compounds containing BH
4−n
X
n
, for example cyanoborohydride (B(CN)H
3
) and triethylborohydride (B(C2H5)3H). Borohydrides find wide use as reducing agents in organic synthesis. The most important borohydrides are lithium borohydride and sodium borohydride, but other salts are well known (see Table). Tetrahydroborates are also of academic and industrial interest in inorganic chemistry.

Lithium borohydride chemical compound

Lithium borohydride (LiBH4) is a tetrahydroborate and known in organic synthesis as a reducing agent for esters. Although less common than the related sodium borohydride, the lithium salt offers some advantages, being a stronger reducing agent and highly soluble in ethers, whilst remaining safer to handle than lithium aluminium hydride.

The chemical reactions described as reduction of nitro compounds can be affected by many reagents and reaction conditions. Historically, the nitro group was one of the first functional groups to be reduced.

In nitrile reduction a nitrile is reduced to either an amine or an aldehyde with a suitable chemical reagent.

Carbonyl reduction

In organic chemistry, carbonyl reduction is the organic reduction of any carbonyl group by a reducing agent.

Trihydridoboron, also known as borane or borine, is an unstable and highly reactive molecule with the chemical formula BH
3
. The preparation of borane carbonyl, BH3(CO), played an important role in exploring the chemistry of boranes, as it indicated the likely existence of the borane molecule. However, the molecular species BH3 is a very strong Lewis acid. Consequently it is highly reactive and can only be observed directly as a continuously produced, transitory, product in a flow system or from the reaction of laser ablated atomic boron with hydrogen.

1,2-Dimethyldiborane chemical compound

1,2-Dimethyldiborane is an organoboron compound with the formula [(CH3)BH2]2. Structurally, it is related to diborane, but with methyl groups replacing terminal hydrides on each boron. It is the dimer of methylborane, CH3BH2, the simplest alkylborane. 1,2-Dimethyldiborane can exist in a cis- and a trans arrangement. 1,2-Dimethyldiborane is an easily condensed, colorless gas that ignites spontaneously in air.

Tetramethyldiborane chemical compound

Dimethylborane, (CH3)2BH is the simplest dialkylborane, consisting of a methyl group substituted for a hydrogen in borane. As for other boranes it normally exists in the form of a dimer called tetramethyldiborane or TMDB (CH3)2BH)2. Other combinations of methylation occur on diborane, including monomethyldiborane, trimethyldiborane, 1,2-dimethylborane, 1,1-dimethylborane and trimethylborane. At room temperature the substance is at equilibrium between these forms. The methylboranes were first prepared by H. I. Schlesinger and A. O. Walker in the 1930s.

Trimethyldiborane chemical compound

Trimethyldiborane, (CH3)3B2H3 is a molecule containing boron carbon and hydrogen. It is an alkylborane, consisting of three methyl group substituted for a hydrogen in diborane. It can be considered a mixed dimer: (CH3)2BH2BH(CH3) or dimethylborane and methylborane. called 1,2-dimethyldiborane. Other combinations of methylation occur on diborane, including monomethyldiborane, 1,2-dimethyldiborane, tetramethyldiborane, 1,1-dimethylborane and trimethylborane. At room temperature the substance is at equilibrium between these forms, so it is difficult to keep it pure. The methylboranes were first prepared by H. I. Schlesinger and A. O. Walker in the 1930s.

Methyldiborane chemical compound

Methyldiborane, CH3B2H5, or monomethyldiborane is the simplest alkyldiborane, consisting of a methyl group substituted for a hydrogen in diborane. As with other boranes it exists in the form of a dimer with a twin hydrogen bridge that uses three-center two-electron bonding between the two boron atoms, and can be imagined as methyl borane (CH3BH2) bound to borane (BH3). Other combinations of methylation occur on diborane, including 1,1-dimethylborane, 1,2-dimethyldiborane, trimethyldiborane, tetramethyldiborane, and trimethylborane (which is not a dimer). At room temperature the substance is at equilibrium between these molecules.

1,1-Dimethyldiborane chemical compound

1,1-Dimethyldiborane is the organoboron compound with the formula (CH3)2B(μ-H)2BH2. A pair of related 1,2-dimethyldiboranes are also known. It is a colorless gas that ignites in air.

References

  1. "SCI Perkin Medal". Science History Institute . 2016-05-31. Archived from the original on 2 February 2018. Retrieved 24 March 2018.
  2. Laylin, James K. (30 October 1993). Nobel Laureates in Chemistry, 1901-1992. Chemical Heritage Foundation. ISBN   9780841226906 via Google Books.
  3. 1 2 3 4 Wilhelm Odelberg (1979). "Herbert C. Brown: The Nobel Prize in Chemistry 1979". Les Prix Nobel. Nobel Foundation. Archived from the original on 2007-08-19. Retrieved 2007-08-27.
  4. 1 2 Negishi, Ei-Ichi (2008). "Herbert Charles Brown" (PDF). National Academy of Sciences. Archived (PDF) from the original on 2015-09-10.
  5. "Herbert C. Brown". Notable Names Database. Soylent Communications. Archived from the original on 2007-09-30. Retrieved 2007-08-27.
  6. "Biography of Herbert C. Brown". Purdue University. 2001. Archived from the original on 2008-03-26. Retrieved 2007-08-27.
  7. "Alpha Chi Sigma Hall of Fame". Alpha Chi Sigma Fraternity. Retrieved 2008-01-07.
  8. "The President's National Medal of Science: Recipient Details - NSF - National Science Foundation". www.nsf.gov. Archived from the original on 2012-10-15.
  9. "Alpha Chi Sigma Fraternity". alphachisigma.org. Archived from the original on 2017-12-07.
  10. 1 2 3 4 5 6 "Archived copy" (PDF). Archived from the original (PDF) on 2014-08-09. Retrieved 2014-05-14.CS1 maint: Archived copy as title (link)
  11. "Illustrated Glossary of Organic Chemistry - Hydroboration-oxidation reaction". www.chem.ucla.edu. Archived from the original on 2014-05-15.