Room temp supercon, more

[UncleAl]

Stanford Department of Physics' William A. Little proposed excitonic high temperature superconductors: organic polymers [-C(Ph)=(Ph)C-]n,

 

Phys. Rev. A 134 1416 (1964)

Phys. Rev. B 13 4766 (1976)

 

Little's 1964 PRA paper has been cited 840 times, including 16 times in 2005. There is sustained interest. "Ph" is phenyl, generic arenes and derivatives; chromophores, fluorophores... Physicists and chemists rarely chat.

 

In 1964 Little molecules could not even be modeled. This is 2006.

 

I can see two classes of quick syntheses of a broad variety of Little's fully substituted high polymer polyacetylenes. Modeling gives energies varying from -600 kcal/mole to +1200 kcal/mole for 16-mers (32-carbon polyacetylene backbones).

 

HyperChem mm+ calculates 16-mers to minimized energy in acceptable run times.

 

http://www.hyper.com/products/Lite/lite20.html

 

http://www.mazepath.com/uncleal/benzen1.png

Base model with benzene hanging off

http://www.mazepath.com/uncleal/pyrene1.png

Look at that huge negative enthalpy for pyrene substitution!

 

Pyrene is by far the deepest hole binding energy. That happy lump has pyrenes on both sides. There's nowhere to run. What happens if we strip one side and replace the bulky pyrenes with tiny hydrogens? Now the molecule can writhe any way it likes to get the fat stuff out of its own face.

 

A single rather than double pyrene substitution/mer demonstrates it really, really likes to stack despite steric interactions,

 

http://www.mazepath.com/uncleal/pyrene1a.png

 

They are still strongly overlapped and interacting though packing no longer forces them to do it. Kewl.

 

LET'S MAKE IT,

 

[arene carboxaldehyde --> diaryl benzoin --> diaryl benzil]

benzil + McMurry coupling --> Little

Mechanical stirring or external vortex mixer. Magnetic stir bars might be counterproductive given the Meissner effect.

 

[PhCHO --> PhCH(OH)-(C=O)Ph --> O=C(Ph)-(Ph)C=O]

O=C(Ph)-(Ph)C=O --> [=C(Ph)-(Ph)C=]n

that is Little's [-C(Ph)=(Ph)C-]n with the bracket window shifted by one atom

 

Parent molecule benzil, Ph=phenyl, costs $(US)0.16/gram. Pyrene-1-carboxaldehyde is $4.03/gram.

 

ADMET living polymerization is more elegant and useful.

 

[arene carboxaldehyde --> diarenyl benzoin --> diarenyl benzil]

diarenyl benzil + Tebbe methylenation --> 2,3-diarenylbutadiene

[diarenyl oxamide + Tebbe methylenation --> 2,3-diarenylbutadiene]

2,3-diarenylbutadiene + ADMET (probably Schrock, possibly Grubbs) --> Little + ethylene

 

I've gone through about a dozen faculty at major universities. I expect Gentle Reader will appreciate America in th 21st century:

 

"If it is a good experiment, somebody else would have done it."

 

They won't look because nobody else has looked. That's an airtight excuse , isn't it? It's the Borromean Ring objection - it holds together as long as everybody plays the game.

 

http://www.paradise.caltech.edu/~cook/Workshop/Math/Borromean/borromean.jpg

http://en.wikipedia.org/wiki/Borromean_rings

 

"Oh beautiful for specious skies... "

[TheBigDog]

LET'S MAKE IT

I have always been intruiged by the prospect of room temperature superconduction. But my interest does not translate into expertise. That being said, I am game to try something like this if it is within my limited means to do so.

 

Would this be doable by a hobbiest with minimal budget and maximal enginuity? Or does it require specialized equipment only found in reaserch facilities of modest to sizable budgets?

 

Bill

[Turtle]

"Oh beautiful for specious skies... "

 

Oh say can I see... Al, you are the man! How's the orchids? I responded to a different thread outlineing your computer modeling of this superconductor, then I found this one.

Any bites yet? What are the physical characteristics of your discovery? That is flexibility, color, hardness, etc.?

I am doing my darndest to remain non-illucid:doh: ; thanks for your forbearence.:steering: