Posts tagged as:

chemistry

About releasing building blocks…

August 19, 2010

A reader asks a general question about mechanosynthesis — How could a device release a reactive molecule once it’s bound to a product? — and I’d like to outline why there are many answers.

 

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The molecular approach
to atomically precise fabrication

March 12, 2010

A few days ago, I wrote a brief sketch of the status and paths forward in the molecular approach to atomically precise fabrication. It offers a sampling, not a full picture:

 

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Chemists deserve more credit:
Atoms, Einstein, and the Matthew Effect

February 17, 2010

Chemists understood the atomic structure of molecules in the 1800s, yet many say that Einstein established the existence of atoms in a paper on Brownian motion, “Die von der Molekularkinetischen Theorie der Wärme Gefordete Bewegung von in ruhenden Flüssigkeiten Suspendierten Teilchen”, published in 1905.
This is perverse, and has seemed strange to me ever since [...]

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Exploiting strong, covalent bonds
for self assembly of robust nanosystems

February 6, 2010

Atomically precise self-assembly of complex structures can be engineered by providing for multiple binding interactions that

Cooperate to stabilize the correct configuration, in a thermodynamic sense, and

Do not stabilize any other configuration, in a kinetic sense

Roughly speaking, in the correct configuration, the parts fit together to allow all the binding interactions to operate simultaneously, and the [...]

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Self-assembling nanostructures:
Building the building blocks

January 25, 2010

This post is prompted by a set of interrelated advances in chemistry that hold great promise for advancing the art of atomically precise fabrication. In this post, I’ll describe an emerging class of modular synthesis methods for making a diverse set of small, complex molecular building blocks.
The road to complex self-assembled nanosystems starts with stable [...]

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Mechanochemistry, Mechanosynthesis,
and Molecular Machinery

April 14, 2009

Volume 1, Number 1 of Nature Chemistry is now out, and the next issue will include an article titled “Activating catalysts with mechanical force”. This article reports a nice experimental result and helps to illustrate the broad range of physical processes included under the umbrella terms of “mechanochemistry” and “mechanosynthesis”.
The authors demonstrate two examples of [...]

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Polyoxometalate Nanostructures

March 29, 2009

My technical talks often include a slide that shows several kinds of atomically precise components that may prove useful in composite nanosystems. One image is labeled “polyoxometalates”, a name that isn’t widely known. I think it should be.
Polyoxometalates (POMs) are molecular structures that are, in effect, atomically precise bits of metal oxide that contain [...]

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Effective Concentration in Self Assembly,
Catalysis, and Mechanosynthesis (2)

March 27, 2009

In my post on effective concentration, I noted that the concentration of water in water (about as high as a real concentration can be) is 55 M, while observed effective concentrations are often >55,000 M. This is puzzling until you realize that, for a molecular collision to result in a reaction, it must typically hit a target [...]

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Effective Concentration in Self Assembly,
Catalysis, and Mechanosynthesis (1)

March 22, 2009

I find that the concept of “effective concentration” helps to clarify my thinking about molecular processes that include catalysis, self assembly, and mechanosynthesis. The concept applies most directly to reaction rates, and it uses ordinary, solution-phase processes as a reference point.
Reactant concentration and reaction rate
In a relevant and typical case, molecules of type A react [...]

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