Wednesday, April 5, 2017

Identification of the Formal +2 Oxidation State of Plutonium #chempaperaday 282

Here is another plutonium paper this month. Looks like March is (was) the plutonium month. I will copy and paste from the abstract so that I don't say anything wrong about the impact of the paper:

"the first structural characterization of a Pu–C bond. Absorption spectroscopy and DFT calculations indicate that the Pu2+ ion has predominantly a 5f6 electron configuration with some 6d mixing."
I really appreciate the team's effort to try to fully characterize the compounds here. Think about it, there is some real radioactivity concern first of all. Secondly, since the plutonium is weapons-grade, I am pretty sure there is a lot of concern about material being lost/wasted etc. Nevertheless, they managed to collect the characterization data that is necessary. In addition to the data, they also provided some photos of the compounds and the crystals which I think are really cool. You don't see plutonium compounds often. What I really liked though is the explanation (which I totally agree) they provided for the solvent impurities in the NMR samples. From the SI:

"Solvent  impurities  in  the  deuterated  solvents  in  this  spectrum  and others  are  difficult  to  eliminate  because a negative pressure glovebox , operated for safe containment of transuranic  α - particle emitting radioisotopes , cannot have the  atmosphere purged for safety reasons (pressure  inside  the  box  must  remain  negative  relative  to  the  laboratory  atmosphere at  all  times ). Once  discovered  by  NMR , it  would  take several weeks  of  work to  repeat  the plutonium experiments  and attempt to remove all traces of solvent  impurities (which may not be successful) . Since these  impurities  do  not  change  the  results  or  conclusions ,  the  aesthetic  improvement  that  might  be  gained from the extensive work required was not pursued."

Overall, great work I think!

Abstract Image

http://pubs.acs.org/doi/pdf/10.1021/jacs.7b00706

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