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Offline Shadow

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Synthesize this!
« on: December 10, 2014, 11:42:49 AM »
I thought about synthesizing some weird molecules. I want to start with the attached fenestrane. Do you have any suggestions about synthesizing it? I thought about some photochemical reactions,but what should be the starting molecule?

Offline OrgXemProf

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Re: Synthesize this!
« Reply #1 on: December 10, 2014, 12:46:16 PM »
So, you would like to synthesize tetracyclo[3.3.1.03,9.0.07,9]nonane, i. e., [4.4.4.4]fenstrane?

You may be the first person today to express this desire, but surely you are aware that others have devoted considerable thought to this exercise in the past.

For example, see: "A Brief Discussion on Fenestranes", which can be found in J. A. Woolford, "The Double [3 + 2] Cycloaddition reaction", Springer-Verlag:Berlin, Chapter 3, pp 41-47.

Some questions/thoughts:

1. What is the likely hybridization of the central carbon atom in [4.4.4.4]fenestrane?

2. Can you cite any other examples of a known compound with a carbon atom that possesses similar hybridization and/or geometry?

3. You might have a look at "Structure and Energetics of [4.4.4.4]fenestrane": Shulman, J. M., et al., J. Am. Chem. Soc., 1983, 105, 743–744.

4. Rest secure in the knowledge that success in your proposed venture will lead to fame and fortune.

5. I would suggest that it may be too soon for you to purchase your new Maserati with the proceeds.


Offline Shadow

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Re: Synthesize this!
« Reply #2 on: December 10, 2014, 12:56:58 PM »
Ok, I will leave this for now, and search for an easier to synthesyze but equally weird molecule.

Offline OrgXemProf

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Re: Synthesize this!
« Reply #3 on: December 10, 2014, 01:01:06 PM »
Discretion: The better part of valor.

Offline OrgXemProf

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Re: Synthesize this!
« Reply #4 on: December 10, 2014, 01:11:07 PM »
Back in the 1990s Randy Thummel (Univ. of Houston) edited a monograph series entitled "Advances in Theoretically Interesting Molecules", published by JAI Press: Greenwich, CT. I'm aware of the existence of at least four volumes in this series.

You may be able to find this publication in a university chemistry (or science) library. Perhaps a glance at some of the individual chapters will lead to some fresh ideas on potential new target molecules for "weird synthesis".


Offline curiouscat

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Re: Synthesize this!
« Reply #5 on: December 10, 2014, 01:15:32 PM »
In the case of "weird" molecules like this one is it possible to say whether it'd be a stable molecule even if one were to synthesize it?

Or are our theoretical methods not good enough yet & the only way to tell is to make one & see?

Offline Shadow

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Re: Synthesize this!
« Reply #6 on: December 11, 2014, 10:37:32 AM »
I don't expect the fenestrane to be flat, rather puckered.

Offline discodermolide

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Re: Synthesize this!
« Reply #7 on: December 11, 2014, 12:11:04 PM »
In the case of "weird" molecules like this one is it possible to say whether it'd be a stable molecule even if one were to synthesize it?

Or are our theoretical methods not good enough yet & the only way to tell is to make one & see?


I think the theoretical methods are reasonably robust and some of these weird molecules were actually predicted to exist before they were actually synthesised. I may have a few examples, if I can find them.
Our colleague Enthalpy would know.
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Offline clarkstill

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Re: Synthesize this!
« Reply #8 on: December 11, 2014, 12:47:54 PM »
These chaps use electrocyclic ring closure to generate a related molecule:

http://pubs.acs.org/doi/abs/10.1021/ja903914r

Offline Shadow

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Re: Synthesize this!
« Reply #9 on: December 11, 2014, 02:26:51 PM »
Extraordinary!

Offline Shadow

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Re: Synthesize this!
« Reply #10 on: December 12, 2014, 11:59:17 AM »
Was ever a square pyramid-like alkane synthesyzed?

Offline Enthalpy

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Re: Synthesize this!
« Reply #11 on: December 14, 2014, 06:32:26 PM »
I'm more interested in compounds in 1t to 200t amounts costing <<1M$ (for rockets), and then mass-production of already made compounds would be an innovation.

For instance diasterane and triasterane look interesting but haven't been mass-produced up to now. Stellane may be nice. Is spiropentane, or better its dimer, available in railcar amounts?

Bicyclo[1.1.1]pentane, or better its (preferably unsymmetric) dimer or trimer (and their mixes), is definitely interesting. The precursor [1.1.1]propellane is obtained by photochemical methods, so the oligomer might just be a matter of mixing the propellane with the proper amount of illuminated iodine or bromine, then replacing the halocarbon with hydrogen.

By the way, last time I evaluated the lamp and electricity cost, photochemical synthesis was affordable even for rocket fuels. Since the better (exciplex) UV lamps are rather new, this field can only increase.

For rocket fuels, tertiary amines are better than hydrocarbons and usually easier to synthesize.

Of course, I want aza and diaza-cubane, methylated to be liquid. Obviously.

O yes: a fuel that ignites very quickly in liquid oxygen (trimethylgallium and -aluminium do that) but doesn't catch fire in air (these are pyrophoric). If any possible... Possibly easier, an oxidizer that lights "kerosene" (RP-1) by quickly contact but is harmless.

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Polymers of bicyclo[1.1.1]pentane and bicyclo[2.2.2]octane? The completely straight chains might be stiff and strong, possibly better than polyethylene, today's hi-tech fibre.

Dumb-looking alkanes like CCC(C)CCCC(C)CCCC(C)CCCC(C)CC could make a nice fluid for aeroplane hydraulics and lubricants, electronics coolant, transformer oil, vacuum grease, and so on, if produced in quantity.

Offline OrgXemProf

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Re: Synthesize this!
« Reply #12 on: December 14, 2014, 09:01:04 PM »
Enthalpy: There is a pesky thing called "specific impulse" (Isp) that plagues potential purveyors of novel energetic materials.

In order to maximize density and Isp one must look to compounds that possess highly compact structures and contain considerable strain energy (think: Eaton & Cole's "cubane").

For many years the US Office of Naval Research funded an extensive program in chemical propulsion. An edited treatise has appeared that summarized progress that accrued in this program up to ca. year 2000 (vide infra).

Although now somewhat dated, individual articles presented the following publication nevertheless afford insight into what it takes to make a noteworthy rocket (or airbreathing missile) fuel:

Roy, G. D., Editor, "Advances in Chemical Propulsion", CRC Press:Boca Raton, FL, 2001. This publication is available online and can be downloaded as a pdf file c/o

http://cnqzu.com/library/Anarchy%20Folder/Rocketry/Propellants%20and%20Fuels/Advances%20in%20Chemical%20Propulsion.pdf

Offline Shadow

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Re: Synthesize this!
« Reply #13 on: December 15, 2014, 02:13:37 PM »
How does stellane look like?

Offline OrgXemProf

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Re: Synthesize this!
« Reply #14 on: December 15, 2014, 10:28:58 PM »
I've been thinking about a suitable synthetic target for Shadow to pursue. Perhaps he might consider the conversion shown in the attachment.

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