White Phosphorus Tamed by Encapsulation

admin — Tue, 14 Jul 2009 21:26:54 +0000

Phosphorus was known since heroic alchemistry times for its propensity to emit light and spontaneously self-ignite when exposed to air. These rather unusual properties make this compound dangerous to handle and transport. The most reactive allotrope of phosphorus is the so-called white phosphorus (also named yellow phosphorus, never mind), which in more modern times became (in)famous for its uses as military weapon and incendiary agent. A quick search on youtube provides several illustrations on the properties and uses (usually controversial) of this chemical.

www.youtube.com/watch?v=Oke8GinWDG8

Now researchers from University of Cambridge in UK and from University of Jyväskylä in Finland report in Science a tetrahedral cage-like molecule which can encapsulate tetrahedral molecules of white phosphorus. In addition of being ‘inactivated’, phosphorus was also rendered water soluble by encapsulation, and both forms, either solid or dissolved in water, were found to be literally indefinitely stable. Interestingly, the release of phosphorus from the cage can be controlled by addition of a competing guest (benzene) which expels phosphorus. Dr. Jonathan Nitschke, who led the research, underlines the potential applications of such container molecules (source: sciencedaily.com): “It is foreseeable that our technique might be used to clean up a white phosphorous spill, either as part of an industrial accident or in a war zone. In addition to its ability to inflict grievous harm while burning, white phosphorous is very toxic and poses a major environmental hazard.” In the future, this method can probably be adapted to target other harmful molecules.

For more information:
P. Mal, B. Breiner, K. Rissanen, J. R. Nitschke, Science 2009, 324, 1697. DOI: 10.1126/science.1175313

ScienceDaily, retrieved July 14, 2009.

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White Phosphorus Tamed by Encapsulation