Chemists Forge Custom Molecules Upon 'Diamond Anvils'

(Credit: Wendy Mao/SLAC National Accelerator Laboratory) Chemistry, Walter White once said, is the study of change. Apply the right combination of materials and heat, electricity, or light — some kind of energy — and the results can literally be explosive. In their quest to manipulate matter, scientists have explored different ways of poking molecules to see how they react. According to a paper that appeared in the journal Nature this week, they’ve found a new one, and possibly the most cartoonish one yet: using tiny anvils to literally bend atoms into shape.ACME-style Research Scientists had studied pulling molecules apart before, but this is the first time “mechanochemistry” has used a mechanical force to squeeze molecules in order to alter their chemical bonds. To generate that force, they used two kinds of anvils: tiny diamond anvils, applying force to the molecule as a whole, and tinier molecular anvils, “harder” bits of the molecules to transfer that force to specific atoms. The diamond anvils are standard science equipment in the SLAC National Accelerator Laboratory where the work took place. A contraption roughly the size of a Solo cup puts two small diamonds (just about a quarter of a carat each) in close proximity, and tightening screws brings them closer together. Anything caught in between can face some extremely strong pressures — like 10,000 times surface atmospheric pressure strong. The tool is useful for seeing how specific materials behave in environments with extreme pressures, like planetary cores. Usually when scientists do that, the material in question deforms “isotropically” — roughly equally throughout. But what if you took a material with some hard and soft bits (“compressible mechanophores” and “incompressible ligands,” in the paper’s language). Would the soft bits give way, but not the hard bits? The Soft Bits Gave Way The team successfully changed the sample’s atomic structure, bending and breaking chemical bonds and even re-distributing electrons. X-rays and computations showed it truly was the work of diamond anvils pushing molecular anvils pushing the softer bits around. The team even refined their approach and embedded “diamondoids” — the smallest diamonds possible, just billionths of billionths of a carat — to better control exactly how a material bends and breaks. It’s cool enough to think we’ve gotten to the point where we can literally shove around the pieces of a molecule. But beyond that, the work gives scientists one more tool in their arsenal for understanding and working with matter, possibly leading to unexpected breakthroughs and cool new materials. Plus, unlike work with heat or caustic solvents or electricity, pushing around molecules is more environmentally friendly, and more energy efficient. This may just be the start of a whole new field of research — to say nothing of the contribution to cool band names. Rock on, molecular anvils!