Posts tagged as:

chemistry

Stronger than carbon nanotubes:
Polyynes and the prospects for carbyne

September 29, 2010

Carbon nanotubes have a reputation for being strongest possible fibers, but polyyne chains are stronger, as measured by the critical strength/density ratio: Polyyne carbon-carbon bonds are stronger than the bonds in graphene and nanotubes, and the bonds are all are aligned with the axis of the fiber, the optimal geometry for carrying tensile stress. A [...]

Read the full article →

Boron is the new carbon…

September 13, 2010

…and I read it in EMBO Reports.
Declaring that “boronate esters are the new [reversible covalent linkers in foldamers and self-assembly]” would be less playful and entertaining, but I say something like that here: “Exploiting strong, covalent bonds for self assembly of robust nanosystems”.

Read the full article →

Forcible, reversible mechanochemistry

September 12, 2010

Chemists at Duke and Stanford have prepared polymers that break and reform C–C bonds when yanked and relaxed (paper here). They engineered these polymers to contain cyclopropane rings in their backbones, using the electron-withdrawing effect of a bridging –CF2– to weaken the critical bond (see figure). Applying intense ultrasound to these polymers in solution [...]

Read the full article →

Chemists deserve more credit (2):
   The 150th anniversary
    of the first international science conference

September 10, 2010

In this week’s Chemical & Engineering News, the American Chemical Society marks the 150th anniversary of the world’s first scientific conference — yes, a chemistry conference — held Sept. 3, 1860, in Karlsruhe, Germany.

August Kekulé Atomic scientist,conference organizer

Friedrich August Kekulé von Stradonitz The guy who gets the credit

August Kekulé suggested idea of holding a conference, [...]

Read the full article →

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.

 

Subscribe

Read the full article →

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:

 

Subscribe

Read the full article →

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

February 17, 2010

Chemists understood the atomic structure of molecules in the 1800s, yet it is often said 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 [...]

Read the full article →

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 [...]

Read the full article →

Self-assembling nanostructures:
Building the building blocks

January 25, 2010

A set of interrelated advances in chemistry holds 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 molecular building blocks, and the more [...]

Read the full article →

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 [...]

Read the full article →

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 [...]

Read the full article →

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 [...]

Read the full article →

← Previous Entries