of light and, you know, despite their conjugated structure, it's really only once one gets past about 20 carbons or a decaion that they actually start absorbing in the visible region. So, the shorter derivatives are usually colorless or slightly yellow.

Even so, though, they have very distinctive UV-Vis absorption spectra, so you see a very distinctive pattern of what would almost look like fingers of the vibrational structure. So, it's quite easy to identify them in solution by this basic framework that's

actually one of the methods that chemists have used to identify polyines as natural products in many different sources, both plants and marine organisms, is this distinctive UV-Vis absorption. As one goes outside of this shorter range, they do become colored in many cases because

they have huge molar absorptivity, so the epsilon values are almost a million, and so for a small molecule, such a huge molar absorptivity in itself is quite interesting. So, as you go beyond, say, 12 acetylenes to 14 acetylenes, you start to take on a yellow

to a yellow-orange color, and then there's a rather beautiful progression from yellow to orange to almost red as you get to the longer derivatives. This is actually quite in contrast to many other conjugated oligomers and polymers and even, you know, for example, graphene or the fullerenes, where you have a beautiful purple color because you have a low-energy absorption at 600 or 650 nanometers, and the

polyines, even in carbine, the expected absorbance is about 480 nanometers, and so you're just barely into the visible region, so it's the polymer, the infinite polymer is probably only going to be a red material rather than a beautiful purple or

blue that one would come to expect with a very conjugated oligomeric system. So, I guess the big question is always why make carbine or what might it be useful for, and that's a pretty difficult question to answer at this point because the challenge

really was the synthesis, and we now only have the ability to start thinking about what we might do with it, but there are several obvious things that we look at right now, and the first thing that comes to mind is if you look at this, you see a molecular wire.

You see a very conjugated molecule that should very easily be able to conduct electricity from one end to another, and so one of the goals that we have working with the physics groups at the University of Erlangen is could we make a device that's made up of carbon allotropes, and so if you imagine taking a segment of graphene, cutting a hole

in graphene or a ridge in graphene which would basically form two electrodes out of graphene, what we're trying to do is to take our polyines, put a fullerene on each end of the polyine which would act as our alligator clip or a way to connect

to the electrodes, and then set this molecular wire down onto a gap of graphene. As a molecular wire, it's really the perfect molecular wire because no matter how you rotate around any of these bonds, you maintain conjugation, you maintain a linear structure, you maintain orientation, I mean it's not flopping around, it can't bend very well,

and so it really has a huge potential as single molecular species as wires. Another thing that is quite an interesting aspect for using these is to use them as precursors

to other carbon allotropes, and so the current hypothesis or one of the current hypotheses for the formation of fullerenes and into nanotubes is that in the gas phase, small segments of carbon come together to form polyines in the gas phase. These polyines grow until they reach approximately the length of 20 carbons,

and then they cyclize, and then you get polyine rings. Three times 20 then gives you C60, and there's a mechanism that you can show how a ring of 60 carbon atoms in an acetylene can coalesce into a C60 molecule. The groups that we use right now on the end, these supertriddle groups,

the triddle group is a well-known leaving group in organic chemistry. It leaves either as a radical or as a carbocation, and the supertriddle groups that we have on should still function as a leaving group. And so what we're working toward right now is to put these down on a surface, and then through some kind of external stimulation that could be heat,

it could be an ionized gas, it could be light, can we knock these triddle groups off of the polyine segment on the surface and generate 20 carbons, 40 carbons, 60 carbons on the surface? The molecule is now on the surface with a lot of energy associated with it.

Will it actually form C60 on the surface of HOPG, and can we watch this mechanism in real time by scanning it with STM? Can we form hybrid systems? Can we use polyines that are aligned on a surface, and through using most likely an ionized gas, can we cross-link them and have them build up segments of nanotubes on a surface as well?

So there's a wide range of surface chemistry that we think we can do using these as precursors or as pure carbon segments where one doesn't have to remove protons to ultimately get to new carbon allotropes.