I was of course quite tickled when my own field won the prize last year so I think it's safe to discount a theoretical or computational chemistry prize from being given out this year (I am thinking of you, David Baker; you'll just have to wait). Contrary to there being absolutely no evidence to support this, I continue to believe that the prize committee does try to preserve a modicum of diversity, so that they don't end up recognizing similar areas every year.
This year I will keep my list short. The past ten years have recognized theoretical/computational chemistry (1 out of 10), biochemistry/bioorganic chemistry (5 out of 10!), organic synthesis (2 out of 10), surface chemistry (1 out of 10) and quasicrystals (1 out of 10) so I am going to be partial to other fields this time.
Top of my list is John Goodenough for being a co-developer of the lithium-ion battery. I have thought for a while now that this is a prize that has probably been neglected because it's too obvious (remember the prize for IVF?). But that's precisely what makes it so important; lithium-ion batteries are everywhere. Giving a prize for batteries will also be a recognition of the growing importance of energy, and especially non-fossil fuel based energy. Another way to recognize the importance of energy would be to award a prize to Michael Grätzel for the dye-sensitized solar cell.
Speaking of electrochemistry, other often cited names are those of Allen Bard and Harry Gray who have devoted their careers to studying electron transfer, albeit in different kinds of systems (Gray mainly in proteins). The last electron transfer prize was given out to Rudolf Marcus in 1992 so its time may be due. Personally I think that the work that Bard and Gray have done is undoubtedly fascinating and important, but I am a little skeptical about whether its broadly applicable enough to get top billing from the Nobel committee.
Another favorite of mine for this year is Ching Tang of the University of Rochester who made key contributions to the organic light-emitting diode (LED). Like the lithium-ion battery the organic LED is also a mainstay of modern life so saluting its utility would be no surprise. There is also a chance that this contribution could be poached by the physicists. Thomson Reuters also has Tang on their list and he has received the 2011 Wolf Prize, which is almost as good as getting a Nobel.
Turning to what I think are less probable but still attractive choices, I think dendrimers (Frechet) and click chemistry (Sharpless) might stand a chance; the former more than the latter in terms of its longer life and more extensive validation in chemistry. Metal-organic frameworks (Yaghi and others) are also probably validated and used enough to be recognized. I don't really see a straight prize for organic synthesis or methodology, partly because two methodology prizes (palladium-catalyzed reactions and metathesis) have been awarded in the last decade. I would love to see a chemistry/medicine prize awarded to Carl Djerassi for his invention of the pill, but I increasingly get the feeling that that ship has sailed for good.
So that's my personal list for this year's chemistry prize - energy as a field is at the top, and LEDs, batteries and electron transfer are my favorite contenders.
Occasionally the prizes for chemistry and medicine overlap so it's worth speculating a bit on the medicine prize. In the "obvious" category are people like Alec Jeffreys (DNA fingerprinting), Leroy Hood and Craig Venter (the nuts and bolts of gene sequencing), Robert Langer (drug delivery) and a longstanding favorite of many people - nuclear receptors (Chambon and Evans; Elwood Jensen sadly passed away in 2012). Thomson Reuters is proposing David Julius who did important work on figuring out the receptors responsible for pain, and that seems like a good choice to me. More speculatively, I feel convinced that there are prizes for CLARITY and CRISPR sometime in the future, but not yet.
Although I can't predict who will win, one thing that I think we can all bet on is that someone will be woken up at the crack of dawn by a phone call, someone will inevitably be left out, and someone's ardent belief in the possibility that his or her favorite scientist was somehow hijacked by a rival field will be shored up by another data point.