Friday Fun - Superlative Publishers

Who's got the highest total # of published papers among living synthetic chemists?

Criteria: The person runs a group that makes things - sorry, no theorists this round - and works principally in some sub-field of synthetic chemistry (organic, organometallic, inorganic, photochem, med-chem, polymers, etc). 

I opened the discussion up on Twitter this morning, and used SciFinder, backed up with [cough] group websites that often need updating [cough]. 

Here's the list, as of 10:00 CST...

(All counts rounded to nearest 100 for convenience. SciFinder is an imperfect metric, since it includes abstracts and some duplicate entries. Please refer to caveats, below, for more detail.)

Alan Katritzky: 2,200 website; 2600 SciFinder

Source: exchangewire.com

Robert S. Langer: 2000 SciFinder

George Whitesides: 1,200 website; 1900 SciFinder

Leo Paquette: 1500 SciFinder

*E. J. Corey: 1,000 website; 1500 SciFinder

J. Fraser Stoddart: 1,000 website; 1400 SciFinder
Tobin J. Marks: 1,000 website, 1600 SciFinder
Paul v. Rague Schleyer: 1,300 website; 1600 SciFinder
Jean Frechet: 800 website; 1300 SciFinder
Irina Beletskaya: 1300 SciFinder

Barry Trost: 900 website; 1200 SciFinder

K.C. Nicolaou: 700 website; 1200 SciFinder

D. Reinhoudt: 1200 SciFinder

J. S. Yadav: 1,000 website; 1200 SciFinder

Ben Feringa: 1100 SciFinder
J-M. Lehn: 1100 SciFinder

E.W. "Bert" Meijer: 1000 SciFinder

Robert "Bob" Grubbs: 1000 SciFinder
Virgil Percec: 1000 SciFinder

Samuel "Sam" Danishefsky: 700 website; 1000 SciFinder

Ryoji Noyori: 800 SciFinder

Steven Ley: 900 SciFinder
Amos B. Smith: 900 SciFinder
James Tour: 500 website; 900 SciFinder
Stuart Scheiber: 500 website; 800 SciFinder
Karen Wooley: 700 SciFinder

Peter Langer: 700 SciFinder
Carolyn Bertozzi: 700 SciFinder
Jean'ne M. Shreeve: 500 website; 700 SciFinder
JoAnn Stubbe: 600 SciFinder

John Hartwig: 300 website; 600 SciFinder

K. Barry Sharpless: 600 SciFinder
Jacqueline Barton: 300 website; 600 SciFinder
Gautam Desiraju: 500 SciFinder
J.K.M. Sanders: 500 SciFinder

Ted Taylor: 500 SciFinder
Laura Kiessling: 400 SciFinder
M. Joullie: 400 SciFinder
Cynthia Burrows: 300 SciFinder
Melanie Sanford: 200 SciFinder

(Update: 1PM - Added Tobin Marks, Virgil Percec. 6PM - Added top-author women chemists. 7PM - Added Frechet, Desiraju, Sanders. 12AM 6/1 - Added Shreeve, Beletskaya)

Some caveats: I know it's folly to attempt correlating total publication count : scientific 'genius.'

If you only publish one paper, but you cure a major disease or invent a top-selling polymer additive, you're doing just fine! 

Also, I note that not everyone agrees that folks on this list belong in the "synthetic chemist" bucket - see ScienceGeist's (noted) exceptions here. (Update: P-O. Norrby noted another exception...)

Importantly, graduate students shouldn't feel down and out about this list. You can have a perfectly fine career with just a handful of papers; these superstars are the exception rather than the rule.

Curious thought: Publications in large synthetic groups certainly seem to follow a power law** - it takes ~15 years to get those first 100 papers, then about 8 for 100 more, and then the pace picks up dramatically. Presumably, this represents added hands and minds, along with building respect and excitement for one's work. I don't know how many other factors (prizes, location, grants, "buzz") are involved, but they probably belong to another post.

Readers, what say you? Have another person I've missed on the list?

*Who knew E.J. pwned ejcorey.com? (show of hands?) I think I smell a fantastic cyber-squatting campaign ...danishefsky.com, anyone?

**An example we discussed on Twitter: Phil Baran. It took him 15 yrs (1997-2011) to get 100 pubs. Next 25 or so have only taken 2 yrs. If power law holds, he'll have >400 pubs by age 50.

Redox Champ: NHC Ipso, Facto

Bond density difference between electron-rich and -poor NHCs
Source: Cavallo, JACS  ASAP

On the surface, N-heterocyclic carbenes (NHCs) seem like dream ligands. They have strong, neutral dative electron pairs, steric bulk, and enough variants now exist that chemists can "dial in" chirality, control R-group rotation, or add them as salts.
Could we possibly improve them any further?

A new JACS ASAP answers: of course! Professor Luigi Cavallo, and KAUST / U. de Salerno coworkers, like to examine NHC ligands computationally. Using Gaussian '09 molecular modeling software, the authors toss in a variety of electron-donating (ex: NMe2, Me) or withdrawing (ex: Br, NO2) substituents on the aryl rings of mock NHC ligands. They then virtually "staple" them onto Grubbs, Grela, and Ir-COD catalysts, and calculate the redox potentials of the Ru and Ir metal centers.

These data trend like you might expect: electron-withdrawing groups on the NHC increase the redox potential, while donating groups reduce it. Well, what's driving these effects? The authors initially suspect σ/π donicity (that's a $5.00 word, right there), the ability of the NHC-M bond to directly influence metal properties. However, they note something odd: there's precious little change in the bond lengths between complexes, only 0.005-0.05Å; by contrast, in carbon-carbon bonding, moving from alkane to alkene shaves off 0.2Å! Thus, they suspect that the NHCs' influence isn't coming through their main bond.

Well, if it's not electronics, then what's changing these redox properties? Enter the 'ipso effect,' a long-observed, yet little-invoked, mechanism for ligand-to-metal charge transfer. The arene carbon directly connected to the heteroatom rubs up against the metal d orbitals, and charge can move through space. Perhaps the best known non-NHC systems to exhibit this effect are the highly-active Buchwald biaryl phosphines, which show ipso interactions with palladium and gold, among other metals. Cavallo and coworkers compare electron density maps (the trippy blue-and-red models, above R) between cationic and neutral metal states, and note a huge red splotch of π-to-d donation (see d) from the NHC orbitals to the metal.

NHC electronics lower intermediate energies
Source: Cavallo, JACS ASAP

But wait, there's more! The authors apply this model to previous observations in Ru metathesis chemistry, then extend the metaphor and tackle Pd biaryl coupling. As shown in the graphic (left), they calculate a ~3 kcal / mol difference for the first catalytic intermediate, depending on the electronic environment of the NHC used. For a throwaway closing line, they let us in on a final trade secret: this effect could be used to stabilize lots of high-valent metal species...do I hear any calls for nickel (IV) chemistry???

Same (Space) Science, Different (Dino) Day

"Five Acids" -  Duplicated in five papers
(PNAS, OLEB, IJC,  TL, JACS)

For those new to the Breslow #spacedino saga, Paul's collection of links back at ChemBark might be the best place to start. Long story short: a tongue-in-cheek press release proclaiming "Dinosaurs from Space!" drew much (unwanted) attention to a prebiotic homochirality review by Columbia University chemistry professor Ronald Breslow. Astute readers and blog commenters noted that the review text strikingly resembled that of earlier papers by the same author.

Well, just how similar were they? Not to incite a flame-war over "least publishable units" (LPUs), but, inspired by ChemBark's commentary on the matter, I've dug through the last six years of Breslow origin-of-life (OOL) publications, and summed up my findings below (Thanks to Paul, Stu, Chemjobber, Ash, Mark, Unity, Martyn, 'Anon,' and everyone else who provided source material for this post!)

"Transamination" - Duplicated in five papers
(TL, OL, OLEB,  IJC, JACS)

Over the last 6 years, I count nine papers that involve, in some fashion, the following topics: homochirality, prebiotic chemistry, enantiomeric amplification, meteorites, or OOL. Here's a list, with full titles, journals, and authorship:

2006 - Tet. Lett. - "Partial transfer of enantioselective chiralities from alpha-methylated amino acids, known to be of meteoric origin, into normal amino acids." Breslow, Levine
2006 - PNAS - "Amplification of enantiomeric concentrations under credible prebiotic conditions." Breslow, Levine
2008 - Org. Lett. - "Enantioselective Synthesis and Enantiomeric Amplification of Amino Acids under Prebiotic Conditions." Breslow, Levine
2009 - PNAS - "On the origin of terrestrial homochirality for nucleosides and amino acids." Breslow, Cheng
2010 - Org. Life Evol. Biosph. - "Imitating Prebiotic Homochirality on Earth." Breslow, Levine, Cheng
2010 - PNAS - "L-amino acids catalyze the formation of an excess of D-glyceraldehyde, and thus of other D sugars, under credible prebiotic conditions." Breslow, Cheng
2011 - Isr. J. Chem. - "Formation of L Amino Acids and D Sugars, and Amplification of their Enantioexcesses in Aqueous Solutions, under Simulated Prebiotic Conditions." Breslow
2011 - Tet. Lett. - "The origin of homochirality in amino acids and sugars on prebiotic earth." Breslow
2012 - JACS - "Evidence for the Likely Origin of Homochirality in Amino Acids, Sugars, and Nucleosides on Prebiotic Earth." Breslow

"Formose" - Duplicated in four papers
(OLEB, IJC, TL, JACS)

*So, for those keeping count at home, that's "Prebiotic" = 7, "Amino Acids" = 7, "Origin" = 4, "Chirality" = 4, "Sugars" = 4...and we're not yet past the titles!

(Throughout the post, I've also compared similar Figures, a task Paul and other bloggers had started tackling. I've examined each one in the context of the other eight.)

Poring over the text, many of the papers fall into similar thematic traps. First, Breslow poses a "big question" or concept (OOL, homochirality, etc.), then discusses the Murchison "carbonaceous chondritic meteorite." Breslow references the work of Cronin and Pizzarello, and discusses circularly polarized light, white dwarf stars, and synchrotron radiation. The Breslow "formose reaction" paper (Tet. Lett., 1959, 22-26) sets the stage for the D sugars, and the group's transamination / amplification work for the L-AA papers.

"Nucleosides" - Duplicated in five papers
(TL, OLEB, IJC, PNAS, JACS)

Dead-center in the most recent four papers (OLEB, TL, IJC, JACS), one finds the Morowitz equation, which explains enantiomeric amplification from tiny initial excesses of single enantiomers. Unfortunately, one also finds the most glaring piece of self-plagiarism: the kinetics paragraph. As noted by Stuart Cantrill and several others, full pages are duped among the separate articles - TL p. 4229 is identical to JACS p. 5-6, IJC from 992-993, and (almost) OELB from 20-21.

Even the dinosaur joke, that witty aside that brought all the attention to the paper in the first place, was repeated three times! (IJC, TL, JACS). This inclusion almost begs the question . . .did Breslow wish to be caught?

Obligatory dinosaur image
Source: stegosaurus.com

Nonetheless, the offending paper has been removed from the JACS website, and further editorial action likely awaits him. I remain puzzled, however. How could an academic legend, a chemical pioneer, a man whose research has launched quite a few stelllar professorships (Gellman, Schepartz, Groves, Grubbs, among others), simply reissue the same science, over and over again, in different journals? Breslow continually mentions "credible" conditions; was this because the papers were less so? There's also the puzzling publication order, from 'worst to first.' Breslow re-publishes tenuous material from TL (Impact Factor = 2.6) in JACS (I.F. = 9.0), where visibility no doubt increases? Generally, high-impact research starts out in high-impact journals, and later trickles down.

Time will tell what will happen to the #spacedino paper. My final hope would be that aspiring academics and graduate students watch the situation unfold, and take care against any similar publishing behavior.

ESPN Anchormen - Secret Chemists?

Just in time for Super Bowl 46 (XLVI, for those playing in ancient Rome), The New York Times recently published a humorous collage of ESPN sportscasters' cliches over the past six months of NFL coverage. One tract specifically caught my eye:

"Ray Rice, dynamite running back — he's literally the catalyst for this Ravens offense."

Ray Rice: The Grubbs II of the Ravens' offense

Wow, two chemical terms in the same sentence! I understand, then, that Ray Rice, in addition to being a nitroglycerin-soaked fiber cylinder with a blasting cap, can also reduce kinetic barriers (tackles?) to fundamental reaction steps (gaining touchdowns, no doubt). 

I can see the similarity, if I look hard enough. After all, both football and chemistry research share collisions, (grid)iron, receivers, and a love of all things statistic. 

Just don't compare high "turnover numbers" (TON)...the NFL doesn't look as kindly on those as scientists do!

Enjoy the big game, everyone. Go Pats!