Archive for the ‘Rankings’ Category

Los Cinco Mejores Químicos Hispanos

Sunday, April 1st, 2012

Aquí está mi lista de los cinco mejores químicos hispanos en la historia:

5. Andrés Manuel del Río – El descubridor del vanadio.

4. Luis Miramontes – Inventor del primer anticonceptivo oral (con Carl Djerassi y George Rosenkranz en Syntex).

3. Mario Molina – Demostró la amenaza de los CFC a la capa de ozono de la Tierra

2. Pedro Cuatrecasas – El padre de la cromatografía de afinidad y un químico médico muy bueno.

1. Severo Ochoa – Descubrió cómo los sistemas biológicos sintetizar ARN

0. Henry Eyring – El padre de la teoría de estados transiciónes nació y se crió en México, pero él era americano.

Power Couples in Chemistry

Wednesday, February 15th, 2012

In honor of Valentine’s Day, I attempted to salvage a post from my (defunct) personal blog in which I had ranked the top 5 “power couples” in chemistry. Unfortunately, the Internet Archive’s spider somehow managed to miss it, and I fear that the thread has been lost forever. All I can remember is that I ranked Jackie Barton & Peter Dervan (Caltech) first, Laura Kiessling & Ron Raines (Wisconsin) second, then somewhere down the line were Mary & David Gin (Illinois). I know that was waaaay back in March 2006, but if you can remember the others, leave a comment.

While controversial rankings have become a staple of ChemBark, I am going to take a pass on updating my list for 2011. It’s just too difficult, though I’d definitely add Christina White & Marty Burke (Illinois) to the mix—I’m a big fan of both.

So, no new rankings, but I do have an interesting story about the old “power couples” post.

As you might imagine, I occasionally receive IRL/human feedback on the blog—both positive and negative. The feedback runs the gamut from dirty looks across hallways to direct, verbal accostings, and it comes from people at all levels of our grand institution (from undergrads to retirees). I am always willing to awkwardly accept praise or criticism, though afterward, I usually end up wishing the discussion had occurred in a comments thread where more people could benefit from it.

So anyway…in March of last year, we had a big party at Caltech to celebrate my current advisor’s 75th birthday. The event was staged on the Saturday before the ACS National Meeting in Anaheim, and many of chemistry’s brightest stars were able to attend. It was a really fun night.

As things were wrapping up, my eyes caught a former grad student from our lab directing a woman through the crowd. I was the obvious target of their advance. The woman’s face was instantly familiar, but it took me a couple of seconds to realize…

Hey, that’s Laura Kiessling!

In the next three seconds, my mind raced through the familiar routine:

Uh, oh…what have I said about Laura Kiessling? Hmmmmm. And this was such a good night. Ugh.

It was great to meet Prof. Kiessling, and as we exchanged hellos, it clicked that I had mentioned her and Ron Raines (who would join the conversation a few moments later) in the “Power Couples” post. Sure enough, that ended up being the first topic of conversation:

LK: We’ve got a bone to pick with you.

PB: Ah, ok.

LK: You had a post on your blog about the top power couples in chemistry, and you only ranked us number #2!

The conversation was all in good fun, and they were both very nice. I conceded that those rankings were many years old and in desperate need of an update.

But, of course, I never delivered that update and I won’t provide it now, either. But if you want to have a go, dear readers of ChemBark, please feel free…

Greatest Chemists of All-Time

Tuesday, January 11th, 2011

Late last week, the editors at Nature Chemistry conducted a Twitter poll to answer the age-old question: “Who is the greatest chemist of all-time?”  Such a conversation falls right in my wheelhouse, and in honour of the lads at NChem, I am going to write this post in English.  (I am qualified to do this, as my mother’s from England.)

The results of the poll are summarized on the NChem blog, Sceptical Chymist.  Of the 86 votes cast, the following chemists received three or more:

Linus Pauling (16)
Dmitri Mendeleev (11)
Antoine Lavoisier (7)
Marie Curie (6)
R.B. Woodward (4)
Michael Faraday (4)
Gilbert Lewis (3)

Perhaps Sir Winston Churchill was right when he said, “the best argument against a democracy is a five-minute conversation with the average voter.”  Incidentally, please follow my Twitter feed (@ChemBark) if you are interested in reading about what I eat for dinner.

With all due respect to my Twitter “tweeps”,  are you daft?  Who picks Marie Curie as the greatest chemist ever?  Yes, she was a fantastic chemist.  She might be most inspirational chemist ever, but the greatest ever?  How could six of you agree on that?

Here’s how I see it using football as an analogy: if Pauling is Manchester United, Curie is Everton; she’s right up there in the top flight, but she’s not qualifying for the Champions League.

There were some other head-scratchers in the also-rans:  Moseley? Noyori? Walden? Cannizzaro?  Don’t get me wrong, they are all great chemists too, but number one?  And let’s go back to Mendeleev.  Yes, the concept of the periodic table is fantastic—and Mendeleev was robbed of a Nobel Prize for it—but I don’t think that this contribution alone is enough to justify a number-one vote.  Others chemists made similar observations as Mendeleev, and even then the work was incomplete.  The work in quantum mechanics that explains why the Periodic Table appears as it does is a greater contribution than the table itself.

Coming up with a rank-ordered list of the greatest chemists is a tough task, but I took a stab at it in the NChem comments thread.  (Since then, I’ve decided to swap my #3 and #4.)

Top 5 Chemists…EVER

5.  R. B. Woodward

He is the supreme deity of organic chemistry, and I’m still not sure he belongs in the top 5.  Nevertheless, the magnitude of his accomplishments in a career that spanned the heyday of the field is humbling.  He won the Nobel Prize in ’65 for his work in organic synthesis, and could have shared in two others: the ’73 prize for organometallics and the ’81 prize for orbital symmetry (the Woodward-Hoffmann rules).

4.  Antoine Lavoisier

A rigorous experimentalist with major contributions to the understanding of gases, nomenclature, chemical education, and analytical chemistry.

3. Willard Gibbs

Laid out the foundation of chemical thermodynamics.  Kind of important.

2.  G.N. Lewis

Discovered the covalent bond and made major contributions to chemical thermodynamics, photochemistry, and acid-base theory.  He probably should have won a share of the ’34 Nobel Prize for the discovery of deuterium.

1.  Linus Pauling

Number one despite his rampant medical quackery.  Applied quantum mechanics to understanding the nature of the chemical bond—a concept that lies at the very heart of chemistry.  Also made major contributions to structural biology, particularly the structure of proteins.  He might have won the race to the structure of DNA had he been privy to the same data as Watson and Crick.

My confidence in these assignments is low; I could easily have overlooked something.  Feel free to ridicule me in the comments.  And just for fun, here’s a blast from the past: my 2006 list of greatest organic chemists.

Top 10: Greatest Organic Chemists of All-Time

Thursday, February 15th, 2007

As part of the ChemBark 2.0 Initiative (set to launch in mid-2018), I want to transfer most of the chemistry-related posts from the old blog on to this one.  Since A Synthetic Environment has been firing off a bunch of top 5 lists, this seems like a good time for a blast from the past: my list of the top 10 organic chemists ever…

Here’s my list of the top 10 organic chemists of all-time, without regard to nationality or sub-specialty. I’m sure that the list is biased towards academic chemists, because their triumphs tend to be more heralded, but I’m sure most of them took plenty of money from industry, too.

10. George Olah

Olah was a giant in the field of physical-organic chemistry and the study of reactive intermediates. With his development of superacids, he was able to study carbocations and essentially end the debate about the existence of nonclassical ions. He has also been celebrated for his work in organofluorine chemistry and organic synthesis.

9. Carl Djerassi

The “Father of the Pill,” Djerassi’s synthesis of the progestagen norethindrone had huge medical and societal consequences–people of the ’60s and ’70s should thank him for all of the uninhibited sex they enjoyed. He is also one of the poster boys (along with Marker and Julian) for using plants as sources of steroidal starting materials needed for industrial syntheses.  Because Djerassi’s pill work can be viewed as a nice, tight package with a profound practical application, I think he’s still got a good shot at picking up a Nobel Prize someday.

8. Paul D. Bartlett

The Bartlett Lab was a physical organic powerhouse, and Frank Westheimer said Bartlett “dominated that field for perhaps four decades.” Bartlett hammered home the concept of using kinetic and stereochemical studies to determine mechanisms, and he elucidated the two-step mechanism of electrophilic additions to olefins and the free radical mechanism of certain polymerizations. He also made important contributions to the study of carbocation stabilization (he synthesized 1-bromonorbornane), hydride transfer, and kinetic vs. thermodynamic control of reactions. Perhaps most importantly, Bartlett is credited with changing the way organic chemistry is taught by introducing the mechanistic perspective that we use today.

7. Sir Robert Robinson

The man made the field of natural product synthesis popular. While he might be condemned for this today, for the latter half of the 20th century, the field drove the discovery and development of new reactions in organic chemistry. His one-step synthesis of tropinone is legendary, and he made fundamental contributions to the structural elucidation and synthesis of steroids, alkaloids, and dyes. He is also credited with inventing the arrow formalism (electron pushing) approach to drawing reaction mechanisms.

6. Jack Roberts

Roberts made numberous contributions to the field of physical-organic chemistry, including his studies of cyclopropylcarbinyl systems and molecular rearrangements. Roberts played a major role in popularizing the use of MO theory among organic chemists and he coined the terms “nonclassical carbocation” and “benzyne.” More importantly, the man essentially brought NMR to organic chemistry. In addition to showing chemists how to use the method to elucidate structure, he pioneered the use of isotopic labels to monitor reaction mechanisms. Despite the fact that NMR is still the single most useful method for the characterization of organic compounds, he hasn’t yet been rewarded with a Nobel Prize. I ask you, where is the justice?

5. H.C. Brown

Sure he won the Nobel Prize for his work with hydroborations, but his contributions to physical-organic chemistry were just as important as those to synthesis. His epic battles with Saul Winstein over the nature of carbocations (classical vs. nonclassical) forced chemists at the time to think critically about how to disprove a mechanism and the existence of a particular reactive intermediate. Of course, Brown’s position on nonclassical ions proved to be wrong, but he made the field better nevertheless.

4. Adolf Johann Friedrich Wilhelm Ritter von Baeyer

Trained by Bunsen and Kekule, Baeyer would go on to win the Nobel Prize in 1905 for his work on aromatic compounds and dyes, which were important at the time for the chemical industry. He is especially famous for his work with indigo. He also synthesized phenolphthalein, fluorescein, and barbituric acid. He studied lactams, terpenes, purines, and polyacetylenes, and conducted seminal work on ring (Baeyer) strain. He also introduced the concept of tautomerization. Baeyer did it all, including training three future Nobel laureates (Fischer, Buchner, and Willstatter) and numerous other famous chemists.

3. Emil Fischer

The German chemist is responsible for developing a number of fundamental synthetic methods, including the Fischer indole synthesis, the Fischer oxazole synthesis, and Fischer esterification. Fischer laid the basis for the entire field of carbohydrate chemistry. His proof of the structure of glucose was a tour de force and don’t forget about his Fischer projections (and his lucky guess). He essentially gave his life to chemistry, as the compounds he worked with literally drove him insane.

2. E.J. Corey

The man is a machine, churning out countless total syntheses, new reaction methods, and well-trained chemists with frightening efficiency. In 2002, he was dubbed “the most cited author in chemistry” by the ACS. His progeny populate both the upper levels of academia and the pharmaceutical industry, and at 77, he’s still going strong.

1. R. B. Woodward

The man is a legend–he revolutionized the fields of structural determination, organic synthesis, and physical-organic chemistry. The Nobel Committee essentially bestowed a lifetime achievement award on him with the ‘65 Prize for “outstanding achievements in the art of organic synthesis,” and he would have won a second in ‘81 for orbital symmetry had he not died in 1979. Some, including Woodward himself, thought that he deserved to share in the ‘73 Prize for the “chemistry of organometallic compounds.” On top of all this, he could drink any other chemist under the table. Salud.

Others meriting consideration (in no particular order): Gilbert Stork, Sir Christopher Ingold, George Hammond, Linus Pauling, Donald Cram, Jean-Marie Lehn, Justus von Liebig, Sir Derek Barton, William von Eggers (the “Bull”) Doering, August Wilhelm von Hofmann

Commenter suggestions: Percy Julian, Grignard, Pasteur, Winstein, Sharpless, Dervan

(more…)

The Top 10 Organic Chemists of All-Time

Sunday, April 16th, 2006

This post originally appeared on www.paulbracher.com

Here’s my list of the top 10 organic chemists of all-time, without regard to nationality or sub-specialty. I’m sure that the list is biased towards academic chemists, because their triumphs tend to be more heralded, but I’m sure most of them took plenty of money from industry, too.

10. George Olah

Olah was a giant in the field of physical-organic chemistry and the study of reactive intermediates. With his development of superacids, he was able to study carbocations and essentially end the debate about the existence of nonclassical ions. He has also been celebrated for his work in organofluorine chemistry and organic synthesis.

9. Carl Djerassi

The “Father of the Pill,” Djerassi’s synthesis of the progestagen norethindrone had huge medical and societal consequences–people of the ’60s and ’70s should thank him for all of the uninhibited sex they enjoyed. Because Djerassi’s pill work can be viewed as a nice, tight package with a profound practical application, I think he’s still got a good shot at picking up a Nobel Prize someday.

8. Paul D. Bartlett

The Bartlett Lab was a physical organic powerhouse, and Frank Westheimer said Bartlett “dominated that field for perhaps four decades.” Bartlett hammered home the concept of using kinetic and stereochemical studies to determine mechanisms, and he elucidated the two-step mechanism of electrophilic additions to olefins and the free radical mechanism of certain polymerizations. He also made important contributions to the study of carbocation stabilization (he synthesized 1-bromonorbornane), hydride transfer, and kinetic vs. thermodynamic control of reactions. Perhaps most importantly, Bartlett is credited with changing the way organic chemistry is taught by introducing the mechanistic perspective that we use today.

7. Sir Robert Robinson

The man made the field of natural product synthesis popular. While he might be condemned for this today, for the latter half of the 20th century, the field drove the discovery and development of new reactions in organic chemistry. His one-step synthesis of tropinone is legendary, and he made fundamental contributions to the structural elucidation and synthesis of steroids, alkaloids, and dyes. He is also credited with inventing the arrow formalism (electron pushing) approach to drawing reaction mechanisms.

6. Jack Roberts

Roberts made numberous contributions to the field of physical-organic chemistry, including his studies of cyclopropylcarbinyl systems and molecular rearrangements. Roberts played a major role in popularizing the use of MO theory among organic chemists and he coined the terms “nonclassical carbocation” and “benzyne.” More importantly, the man essentially brought NMR to organic chemistry. In addition to showing chemists how to use the method to elucidate structure, he pioneered the use of isotopic labels to monitor reaction mechanisms. Despite the fact that NMR is still the single most useful method for the characterization of organic compounds, he hasn’t yet been rewarded with a Nobel Prize. I ask you, where is the justice?

5. H.C. Brown

Sure he won the Nobel Prize for his work with hydroborations, but his contributions to physical-organic chemistry were just as important as those to synthesis. His epic battles with Saul Winstein over the nature of carbocations (classical vs. nonclassical) forced chemists at the time to think critically about how to disprove a mechanism and the existence of a particular reactive intermediate. Of course, Brown’s position on nonclassical ions proved to be wrong, but he made the field better nevertheless.

4. Adolf Johann Friedrich Wilhelm Ritter von Baeyer

Trained by Bunsen and Kekule, Baeyer would go on to win the Nobel Prize in 1905 for his work on aromatic compounds and dyes, which were important at the time for the chemical industry. He is especially famous for his work with indigo. He also synthesized phenolphthalein, fluorescein, and barbituric acid. He studied lactams, terpenes, purines, and polyacetylenes, and conducted seminal work on ring (Baeyer) strain. He also introduced the concept of tautomerization. Baeyer did it all, including training three future Nobel laureates (Fischer, Buchner, and Willstatter) and numerous other famous chemists.

3. Emil Fischer

The German chemist is responsible for developing a number of fundamental synthetic methods, including the Fischer indole synthesis, the Fischer oxazole synthesis, and Fischer esterification. Fischer laid the basis for the entire field of carbohydrate chemistry. His proof of the structure of glucose was a tour de force and don’t forget about his Fischer projections (and his lucky guess). He essentially gave his life to chemistry, as the compounds he worked with literally drove him insane.

2. E.J. Corey

The man is a machine, churning out countless total syntheses, new reaction methods, and well-trained chemists with frightening efficiency. In 2002, he was dubbed “the most cited author in chemistry” by the ACS. His progeny populate both the upper levels of academia and the pharmaceutical industry, and at 77, he’s still going strong.

1. R. B. Woodward

The man is a legend–he revolutionized the fields of structural determination, organic synthesis, and physical-organic chemistry. The Nobel Committee essentially bestowed a lifetime achievement award on him with the ‘65 Prize for “outstanding achievements in the art of organic synthesis,” and he would have won a second in ‘81 for orbital symmetry had he not died in 1979. Some, including Woodward himself, thought that he deserved to share in the ‘73 Prize for the “chemistry of organometallic compounds.” On top of all this, he could drink any other chemist under the table. Salud.

Others meriting consideration (in no particular order): Gilbert Stork, Sir Christopher Ingold, George Hammond, Linus Pauling, Donald Cram, Jean-Marie Lehn, Justus von Liebig, Sir Derek Barton, William von Eggers (the “Bull”) Doering, August Wilhelm von Hofmann

(more…)