Sciencemadness Discussion Board - A ring of Benzene rings?

A ring of Benzene rings?

ssdd - 26-9-2007 at 18:55

So I was pondering and I was wondering...

Is it possible to arrange benzene rings with each other to form a larger complex ring? This seems like it would involve 6 benzene rings attached to one another at minimum to work. But I am unsure If there is a chemistry that forbids this from working.

If this could be done this would be a fascinating compound to work with.... Any ideas as to what this may be called? Hexaphenylwhat?

-ssdd

[Edited on 26-9-2007 by ssdd]

guy - 26-9-2007 at 19:39

Yes it is possible.

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

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

[Edited on 9/26/2007 by guy]

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

[Edited on 9/26/2007 by guy]

sparkgap - 26-9-2007 at 19:50

You have coronene and the [n]-circulenes in the extreme.

Coronene is flat, while the other circulenes are either bowl or saddle shaped.

I think it rather unfortunate that most of these have carcinogenic potential...

sparky (~_~)

maingroupe - 26-9-2007 at 20:34

I just drew this:

woelen - 26-9-2007 at 22:40

In fact, the system can be extended in two dimensions. In the limit, you'll end up with a sheet of graphite. Real graphit in fact is a system of sheets of hexagons of carbon atoms.

chemrox - 26-9-2007 at 23:57

ahh then put it in a press and voila! little shiny shit....

ssdd - 27-9-2007 at 03:41

Thanks for the input, I just wasn't sure how difficult it would be to put that last ring into place and if it would be possible at all.

Would there be any interesting chemistry that would arise from a structure like that of coronene other than it being an interesting compound?

Thanks for the info guys,
-ssdd

JohnWW - 27-9-2007 at 05:09

When I was at Victoria University of Wellington, N.Z., in the late 1960s, the then Professor of Organic Chemistry (W.E. Harvey) and some graduate students there were interested in synthesizing hexahelicene, which is similar to coronene except that there is a break in the ring of 6 fused benzene rings so that the broken-end pairs of C atoms "clash" with each other and be forced out-of-plane; and the homolog with one further benzene ring, heptahelicene, in which geometry would force one of the end benzene rings to be out-of-plane and fully overlap the one at the other end of the broken ring - spiral, if you like. Because, in both compounds, the ends of the broken ring are forced out-of-plane, they (and their substituted derivatives) are chiral, existing in optically active enantiomers, and the solids would be as left-and right-handed crystals.

I found 1,370 results for hexahelicene on Google, including one on measurement of its optical rotatory dispersion; and 458 results for heptahelicene, in similar vein. However, I was unable to definitely find a reference to Prof. Harvey's work on them in the late 1960s or early 1970s.

BTW Coronene, along with pyrene, benzpyrene, phenanthrene, anthracene, tetracene, pentacene, hexacene, etc. , and hydrocarbon-chain substituted derivatives of them, occur in tarry products resulting from the pyrolysis with a shortage or absence of air of carbohydrates, e.g. in tobacco smoke. They are extremely carcinogenic, due to their reaction with and bonding to body tissues.

Blind Angel - 27-9-2007 at 06:33

Somebody once told me that he was at a lecture where the guy was explaining how to make interlaced benzene ring, like a chain if you prefer, with no link between each of them. Anybody has more info on this, he wasn't able to give me much more since he didn't remember much.

chemrox - 27-9-2007 at 07:40

These are among the molecules called "polynuclear aromatic compounds" and would be of a subclass of the PNA's. PNA's are nasty as has been mentioned. Now the chain concept is interesting! It seems as possible as placing a metal ion in the center of cubane which has been done. "Bucky balls" have had ions inserted in them too I believe. When the thread started I thought what was meant was something different-where the rings were oriented such that only a single bond connected the rings at each end. Hexagon-hexagon-hexagon-etc. eventually making a circle with virtually no constriction.

Fleaker - 27-9-2007 at 13:40

They smell as nastily as they are for you, believe me! There is very interesting chemistry with those fused rings. Some of my work deals with vegetable and animal lipid pyrolysis and pyrene, benzpyrene, phenanthrene, anthracene, tetracene, pentacene, hexacene are all components in the tar fraction produced.

I should probably mention that pyrolyzing a vegetable oil is a a fairly useful way to make a lot of benzene. How useful? U2U me and I'll tell you. The yields are better than you would think.

feacetech - 27-9-2007 at 14:00

another interesting aromatic is ferrocene.

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

When I was still at school it was beining investigated for a possiable molecular computer chip.
The eclipsed and stagered states were very similar in energy (0,1).

ssdd - 27-9-2007 at 14:13

So with the hexahelicene, could this be expanded to make a larger spiral? Or is it simply limited to the six phenyls? Because if you could expand this to be much larger it could have some interesting polymer possibilities or am I a bit off track (as is always possible

Quote:

It seems as possible as placing a metal ion in the center of cubane which has been done. "Bucky balls" have had ions inserted in them too I believe.

^^ How on earth would one go about inserting ions into these structures without damaging them?

-ssdd

The_Davster - 27-9-2007 at 14:14

Quote:

Originally posted by Blind Angel
Somebody once told me that he was at a lecture where the guy was explaining how to make interlaced benzene ring, like a chain if you prefer, with no link between each of them. Anybody has more info on this, he wasn't able to give me much more since he didn't remember much.

I remeber a thread on them from several years ago, or at least on a chain of cyclic molecules, perhaps not benzene. I was looking for that thread a while ago as well but could not find it.

sparkgap - 27-9-2007 at 17:38

"When the thread started I thought what was meant was something different-where the rings were oriented such that only a single bond connected the rings at each end. Hexagon-hexagon-hexagon-etc. eventually making a circle with virtually no constriction."

- that would correspond to the cyclophanes, CRX.

Another interesting possibility off the top of my head is to fuse benzene rings in a manner that they look like a barrel hoop; not sure if this has been done, though. Somewhat similar to the peculiar substance cucurbituril, I would think.

"I should probably mention that pyrolyzing a vegetable oil is a a fairly useful way to make a lot of benzene. ...The yields are better than you would think. "

- quite the surprise for me...

Controlled pyrolysis, I hazard?

"So with the hexahelicene, could this be expanded to make a larger spiral? Or is it simply limited to the six phenyls?"

- last time I checked the records, [12]-helicene was the largest homolog that has been made; it may or may not be possible that someone has already picked up from where the original investigators left off...

sparky (~_~)

ssdd - 27-9-2007 at 18:45

I have been doing some searching hoping to find some information regarding polymer like formations that could be formed from helicene and I found this link: http://nuckolls.chem.columbia.edu/pdf/4.pdf

It gives some interesting data about helicene fibers and how they are arranged.

Would anyone have any ideas on the synthesis of helicene by any chance? If anyone is interested in working on this please post it here or U2U me, I'd also be interested in methods of attaching individual helicene molecules together.

-ssdd

** In 1975 [14]Helicene was prepared, a little bit longer...

[Edited on 27-9-2007 by ssdd]

Antwain - 27-9-2007 at 19:32

@ssdd - We have an interesting hard copy article at my uni about this, from New scientist '02 I think. Anyhow, how to "cram xenon into a buckyball"

http://www.chemistry.org/portal/a/c/s/1/feature_pro.html?id=...

I personally would not be inspired by 0.3% yields especially after using 3000atm pressure.

Also had to include this, because I personally find it funny. The product is 129Xe@C60.... and no, I am not replying to C60

[Edited on 28-9-2007 by Antwain]

chemrox - 27-9-2007 at 20:49

I have no idea how they insert ions into cubane or buck balls.. was told about it by a chem prof when I was in school and never looked it up or thought about much until the thread started.

"Somewhat similar to the peculiar substance cucurbituril, I would think." Sounds like interesting material. Is it from the cucumber family? curcurbitaceae? too cool ... does it help in the structure of the vines? a lot of questions come up on that one .. thanks!

Antwain - 27-9-2007 at 21:04

Ummm, also, about inserting ions, rather than inert gasses.... I dont think you can. What you do is you make a rod of C + some metal and you evaporate it in an arc. If the mess that forms, you get some C60, and even less C60 with stuff inside it. Probably you can change the charge later. This week we covered research that was done at my uni some time ago concerning adding electrons to buckyballs, so I have little doubt you can do electrochemistry on stuff inside buckyballs too.

ssdd - 28-9-2007 at 04:28

So actually getting the metal into the buckyball is not hard, but how do you separate the buckyballs with metal and the ones without? I assume some kind of GC would work for this but likely damage the product along the way... Some other form of chromatography perhaps?

-ssdd