German team finds a way to link boron atoms with a triple bond

Jun 15, 2012 by Bob Yirka report

(Phys.org) -- In the chemical world, there are few instances where atoms form triple bonds (where three electrons from an atom are bonded with the electrons from another atom). In fact other than triple bonds between carbon and nitrogen few examples exist at all. One instance that theory had predicted should work was with boron, mainly because of where it sits on the Periodic Table of Elements, but also of course because in its stable state it has just three electrons. Because of this, various chemists over the years have tried to figure out a way to form a compound made of triple bonded boron atoms. Now, it appears a team in Germany at the University of Würzberg, has succeeded. They have published a paper describing their results in the journal Science.

Two get two to triple bond with one another, you can’t just shove them together and hope they will stick because they are too stable in their current state. In other words, they’ll just ignore one another. To get them to bond some external force must be introduced. Prior researchers had tried using a laser as a force, but only succeeded in creating a triple bound that could exist at eight degrees above absolute zero. At room temperature it vaporized.

The German team took another approach, instead of trying to push the atoms into bonding, they coaxed them together by slowly filling the places that the three can exist around the nucleus with something else, essentially leaving them no choice but to bond with the electrons from another boron atom. To do that, they introduced a molecule that contained carbon and atoms, called a N-heterocyclic carbine (NHC) in a sterile vacuum chamber. The idea is that because main-group elements such as boron are most stable when surrounded by eight electrons, creating an environment where the boron could share two electrons from the NHC would leave three openings for electrons from one boron atom to be shared with those of another. Thus, the three electrons from each would form bonds with each other naturally to create the full complement of eight electrons. To make it happen they induced a boron-boron double bond as a first step, and then a triple bond in the second.

The result is a green crystal that will exist at room temperature indefinitely in the absence of air or water. Because the discovered process and resultant material is still so new, scientists don’t really know if it might be useful for anything, but the fact that the team has finally solved the riddle of how to get boron to triple bound, will assure them a place in the history books.

Explore further: Repeated self-healing now possible in composite materials

More information: Ambient-Temperature Isolation of a Compound with a Boron-Boron Triple Bond, Science, 15 June 2012: Vol. 336 no. 6087 pp. 1420-1422. DOI: 10.1126/science.1221138

ABSTRACT
Homoatomic triple bonds between main-group elements have been restricted to alkynes, dinitrogen, and a handful of reactive compounds featuring trans-bent heavier elements of groups 13 and 14. Previous attempts to prepare a compound with a boron-boron triple bond that is stable at ambient temperature have been unsuccessful, despite numerous computational studies predicting their viability. We found that reduction of a bis(N-heterocyclic carbene)-stabilized tetrabromodiborane with either two or four equivalents of sodium naphthalenide, a one-electron reducing agent, yields isolable diborene and diboryne compounds. Crystallographic and spectroscopic characterization confirm that the latter is a halide-free linear system containing a boron-boron triple bond.

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El_Nose
not rated yet Jun 15, 2012
here's to hoping its superconductive and more amazing than graphene -- :)
antialias_physorg
4.6 / 5 (9) Jun 15, 2012
Others would say "this has no immediate technical applications", so no money should have been wasted on this.

But you really never know what will come of research. It's just different from "development" or "engineering" where you already know which way to go.

Boron sheets and Boron nanotubes already show amazing properties (some even exceeding those of graphene). So seeing what triple -bonded Boron can do should be interesting.
Scottingham
5 / 5 (5) Jun 15, 2012
Plus 10 to antialias. We need way more basic research!
chardo137
not rated yet Jun 15, 2012
"One instance that theory had predicted should work was with boron, mainly because of where it sits on the Periodic Table of Elements, but also of course because in its stable state it has just three electrons."
Boron has 5 electrons, it has 3 valence electrons.
Shabs42
5 / 5 (2) Jun 16, 2012
Others would say "this has no immediate technical applications", so no money should have been wasted on this.

But you really never know what will come of research. It's just different from "development" or "engineering" where you already know which way to go.


I agree completely, I actually thought this was an awesome line:

. Because the discovered process and resultant material is still so new, scientists dont really know if it might be useful for anything
Mike_Massen
2.3 / 5 (3) Jun 16, 2012
This reminds me of the history of the laser, a laboratory curiousity looking for an application, it took a while, decade or two but, now we are so dependent upon it in many disciplines...

I'm pretty sure that with all various analytical tools and advanced instruments at our collective disposal that opportunities for at least one practical and useful application will come *far* sooner, I'll be back to check on this in a week or less ;-)

With all the amazing stuff even just with graphene, pyrolytic carbon and magnetics etc, Eg
http://www.youtub...tIsnG71U

The potential for the world to change significantly is approaching the asymptote of certainty and more so with compounding !

The Permutations and Combinatorial Complexity is making my finite hairs stand on end longer and longer, I'm starting to look crazy to other crazy people as well :P
goldflinger
not rated yet Jun 16, 2012
kryptonite :)

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