Category Archives: Nobel Prize

The Nobel Prize in Chemistry 2013


I’m quite late to jump on this wagon but nonetheless I’m thrilled about this year’s Nobel Prize in Chemistry being awarded to three awesome computational chemists: Martin Karplus (Harvard), Michael Levitt (Stanford) and Arieh Warshel (USC) for the development of computational models at the service of chemistry; most prominently, the merging of computations both at the classical . and quantum levels, the former allows for a computationally feasible calculation while the latter provides the needed accuracy for the description of a chemical process.

Nobel Laureates in Chemistry 2013 (source: NBC.com)

Nobel Laureates in Chemistry 2013 (source: NBC.com)

As a computational chemist myself I must say that, at some level, it feels as some sort of vindication of the field, which makes me wonder if it indeed needs it, I don’t think so but maybe some might. Last week, Nobel week, I attended a symposium on the Advances in Quantum Chemical Topology where big names such as Paul Ayers, Paul Popelier and Chérif Matta among many others participated along with my friends and colleagues from CCIQS, Fernando Cortés (whom actually organized the whole thing! Kudos, Fer!) and Vojtech Jancik who contributed to the experimental (X-ray diffraction methods) part of the symposium. Surprisingly nobody at the conferences mentioned the Nobel Prize! Not even during the round table discussion titled “The Future of Quantum Chemical Topology“. At some point during this discussion the issue of usefulness came out. I  pointed out chemists have this inherent need of feeling useful, including computational chemists, as opposed to physicists of any denomination. Computational or theoretical chemists try to be like physicists yet still have chemistry behavior baggage. Even more baffling is the fact that at such an abstract conference usefulness is discussed, yet those theoretical chemists who do not develop new methods, nor dwell into equations or propose new Hamiltonians, but rather make use of well established methodologies for tackling and solving particular problems in chemistry become somewhat ostracized by the theoretical chemistry community*.

Much controversy among the comp.chem. community was aroused by this much deserved award (try reading the comment section on this post by the great Derek Lowe at In The Pipeline). Here in Mexico we have a saying: “Ni son todos los que están ni están todos los que son” which is hard to translate given the two different meanings of the verb To Be, but it can be roughly translated as “Not all the ones who should be are present, nor the ones that are present are all that should be“, or something like that. Of course there are many other computational chemists that are left behind from this prestigious prize, but the contributions of Karplus, Levitt and Warshel to chemistry through the use of computational chemistry can be denied. In fact this does vindicate the field of comp.chem. by acknowledging the importance of modelling in molecular design and reactivity understanding.

Congratulations from a Mexican fan to Professors Karplus, Levitt and Warshel for the most deserved Nobel Prize in Chemistry 2013!

PS a much better post on this topic can be found at the curious wavefunction.

Thanks for reading, liking, rating and commenting

*Of course this is just my opinion and views (which is redundant to state since this is my very own blog!)

It’s that time of the year again… The Nobel Prizes


Around early October the scientific community -or at least part of it- starts getting excited about what could be considered the most prestigious award a scientist could ever achieve: The Nobel Prize.

The three categories that interest me the most are: Chemistry, Physics and Literature. I’m not saying I don’t care for the other three (well, maybe the one in economy is way out of my league to grasp) but these three are the ones that always arouse my curiosity. This year laureates have really had me excited! For starters, in chronological order of announcement, Geim and Novoselov seem to be quite younger than the average recipient (52 and 36 years old, respectively). But so is the field for what they got it since the first paper these two scientists from the University of Manchester published on the topic is only about six years old. Discovery of Graphene and most importantly the characterization and understanding of its properties is one of the most promising areas in materials sciences since graphene exhibits very interesting electronic as well as structural behaviors. Nobel prizes are always controversial, but we have to admit that although graphite has been around us for ages, these two England-based Russian scientist have kicked off a promising area of science that will no doubt contribute to further technological developments we can only begin to imagine.

On the other hand, the Nobel Prize in Chemistry was awarded to Heck, Negishi and Suzuki for their work on Pd (palladium) catalyzed coupling reactions. What I liked the most about this prize is that a few years ago I published alongside Dr. David Morales-Morales from the National Autonomous University of Mexico, a paper in J. Molecular Cat. A., in which we performed  a systematic study of a phosphane-free Heck reaction for a series of Pd catalysts with the general formula [ArFNH]PdCl2 (ArFNH = Fluorinated or polyfluorinated aniline). In this paper theoretical calculations were used to assess the relationship between the substitution pattern in fluorinated anilines upon the catalyst’s eficiency, a sort of small quantum-QSAR. Another thing that got me (and a bunch of other chemists) excited was the fact that this year the Nobel Prize in Chemistry went to people working in old fashioned synthetic chemistry, so to speak. Recently a long list of researchers working on the field of BIO-chemistry were awarded the prestigious prize, which comes to no surprise since the development of the Human Genome Project has, and will continue to have, a huge impact in biotechnology. Be that as it may, good for Heck, Suzuki and Negishi and the Pd-catalyzed-carbon-carbon-bond-forming-reactions!

About my initial remark: For reasons I don’t know (I wont subscribe to any of the existing urban-legend-level hypothesis) there is no Nobel Prize in Mathematics, although a lot of mathematicians have been awarded the Nobel Prize in Economical Sciences. For mathematicians the Fields Medal would be the equivalent of a Nobel Prize. However, the Fields Medal is only awarded every four years. Four years ago, this captivating character named Grigori “Grisha” Perelman was awarded the Fields Medal for solving what the Clay Institute in Massachusetts deemed one of the problems of the millennium: The Poincare Conjecture. What is so noteworthy is that Grisha (diminutive for Grigori in Russian) rejected the medal as well as the million dollars awarded by the Clay Institute for solving it. He also rejected a position at Princeton University. His lack of faith in any institution was also reflected in his work, since he did not publish his solution to Poincare’s conjecture in any peer reviewed journal but instead uploaded it on-line and alerted some notorious mathematicians he had worked with in the past about it. Secluded in his St. Petersburg apartment, this remarkable fourty year old, Rasputin-looking-genius, mathematician keeps rejecting not only all fame, money and glory but human contact altogether. It is said that at some point Sir Isaac Newton did the same thing. I guess great minds do think alike.

Pauling hybridization model


Is the C atom in methane sp3 hybridized because it’s tetrahedral or is it tetrahedral because it’s sp3 hybridized? It’s funny how many students think to this date that the correct answer is the latter; specially those working in inorganic chemistry. I ignore the reason for such trend. What is true is that most chemistry teachers seem to have lost links to certain historical facts that have shaped our scientific discipline; most of those lay in the realm of physics, maybe that’s why.

What Linus Pauling, in a very clever way, stated was that once you have a set of eigenvectors (orbitals) of the atomic Hamiltonian any combination of them will also be an eigenvector (which is normal since one of the properties of Hermitian operators is that they are linear); so why not making a symmetry adapted one? Let’s take the valence hydrogenoid orbitals (hydrogenoid being the keyword here) and construct a linear combination of them, in such a way that the new set transforms under the irreducible representations of a given point group.  In the case of methane, the 2s and 2p orbitals comprise the valence set and their symmetry-adapted-linear-combination under the Td point group constitutes a set of new orbitals which now point into the vertexes of a tetrahedron. Funny things arise when we move to the next period of the table; it has been a controversy for a number of years the involvement of empty d orbitals in pentacoordinated P(V) compounds. Some claim that they lay too high in energy to be used in bond formation; while others claim that their involvement depends on the nature (electronegativity mainly) of the surrounding substituents.

In many peer reviewed papers authors are still making the mistake of actually assigning a type of hybridization to set of valence orbitals of an atom based on the bond angles around it. Furthermore, it is not uncommon to find claims of intermediate hybridizations when such angles have values in between those corresponding to the ideal polyhedron. Symmetry is real, orbitals are not; they are just a mathematical representation of the electron density distribution which allows us to construct mind images of a molecule.

Linus Pauling is one of my favourite scientific historical figures. Not only did he build a much needed at the time bridge between physics and chemistry but he also ventured into biochemistry (his model of an alpha-helix for the alanine olygopeptide became the foundation to Watson & Cricks later double  helix DNA model), X-ray diffractometry, and humanities (his efforts in reducing/banning the proliferation of nuclear weapons got him the Nobel Peace Prize long after he had already received the Nobel Price in Chemistry). He was a strong believer of ortho-molecular nutrition, suggesting that most illnesses can be related to some sort of malnutrition. Linus Pauling and his book On the Chemical Bond will remain a beacon in our profession for the generations to come.

 

Disclaimer: The question above, with which I opened this post, was taken from an old lecture by Dr. Raymundo Cea-Olivares at UNAM back in the days when I was an undergraduate student.

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