Read at your own perylene
April 15th, 2008 by excimer[0] Time for another hard-hitting post that asks the important questions: what’s pretty and has pretty colors?
This is perylene. It’s yet another polycyclic aromatic hydrocarbon (PAH), and probably the one of the largest pure PAH that is soluble in most organic solvents. It’s unbelievably fluorescent. So fluorescent, in fact, that ambient light is enough to see its blue fluorescence in solution. [1]
This is a pretty dilute solution of perylene in acetone under ambient light. The blue twinge is from its fluorescence. Shallow solutions of the stuff appear green as a result, like when I was filtering a solution with some perylene in it. [2]
I just thought this next pic was pretty.
And when you put a blacklight (365 nm) up to a solution of the stuff:
It just GLOWS.
[0] Yeah, you liked that pun. Admit it.
[1] You can derivatize perylenes too- the most popular being the perylene diimides (PDI), which are brilliantly colored and can fluoresce anywhere from the yellow to near-IR region, depending on the substitutents. viz:
[2] That mess in the back of the hood was there when I moved there. I don’t want to know what it is.
Nobody has managed to make an electroluminescent system lase (fast mix streams of PAH radical anions and radical cations or generate both at a striped electrode). Organic chemistry is so much the poorer for not having an easily accessible 100 watt death beam. So close…
MWAHAHAHA! You just gave me a post topic…
I know this is over a year late, but as my name implies I am an aspiring chemist, and would greatly appreciate knowledge on how you synthesised this. I saw this a few days prior and have been thinking about how it could be done. I was thinking of using the Suzuki-Miyaura reaction to couple 1, 8-dichloronapthalene to napthalene using a Grignard reagent. This is pretty complicated and deals with a few nasty chemicals, and seeing as how I am 18, inexperienced, and probably WRONG about the synthesis, I thought I’d give asking you a try. Thanks.
BTW i couldn’t just leave a response, for some reason i had to reply to Uncle Al, although I would be just as thirlled to get an answer from him.
PS- Just found the comment: ‘Perylene is the first condensate of naphthalene, if you do a pyrolysis or condensation by Fiedel-Crafts.’ Will look into it, but would still appreciate a response. Thanks again
I didn’t synthesize it- I found it. These pictures, I believe, are from me recrystallizing some perylene my group had bought some years back. Probably the easiest way to make substituted perylenes from some smaller PAH starting materials would be to use either a suzuki or Kumada coupling with 1-substituted naphthalenes to make the 1,1′- binaphthyl, then Scholl coupling with copper(II) triflate/AlCl3 or FeCl3/CH3NO2 up to the perylene. Klaus Müllen developed this approach, and has published a few papers on it in recent years.
Could you please explain 1,1′- binaphthyl, or send the InChI, for some reason I can’t find it online and my ACD Chemsketch is only producing 1,1′- binaphthalene. Also, would a halide suffice instead of OTf? i r poor and dumb. Thanks, you are awesome. I, too, love kittens and chemistry!
Same as 1,1′-binaphthalene-2,2′-diol? At this point this is purely an excersize, I doubt I’ll try this.
Perylene is one of the simpler PAHs that fluorescence. Being so small, it is easy to make and derivatize. Its higher-wavelength characteristics make it unique among small PAHs in being pretty visible. The others of five or less rings are purple or in the UV, but when you get above six rings, many fluoresce in the green, yellow, orange, red, and near IR.
The crystals undergo room-temperature phosphorescence. So put those under a blacklight and you’ll get even higher wavelength emission. The post on trapping them in a graphene structure is not quite correct, as graphene would not be an inert matrix as far as exchange of energy being a PAH and the graphene layers. A great inert matrix for that behavior is perhydrocoronene (PHC)- the fully hydrogenated, somewhat planar hydrocarbon.
Coronene trapped in PHC has an intense yellow phosphorescence with a halflife of 30 seconds to a minute, so you can have some of it in room light, then turn the lights off, and the phosphorescence slowly fades (in molecular terms this is ages).
If you can get some, violanthrone or its isomer isoviolanthrone are PAH diketones once used as dyestuffs (TCI used to carry them). They are purple in color and their solutions fluoresce intensely in the red. Very cool-looking in vials sitting on a desk or lab bench.
Fetz the chemist
Hi John! I have your analysis of PAH’s greater than 24 carbons book on my desk.
I’ve noticed the solid-state phosphorescence. I can take a picture of that. It’s pretty cool.
I’m not sure what you meant by the graphene trapping post not being correct. I meant that for analysis of 2D networks by STM, HOPG aligns the adsorbates parallel to the surfaces. I didn’t mean to say that HOPG was completely innocent in that regard.
Picture? Please??
It would make your super-sick coblogginator feel better…
I meant that graphene interacts electronically with pi networks it stacks against. Each layer is not in an inert sandwich where its behavior remains similar to it not being trapped. The larger PAHs, as an example, show this by decreasing the excited state lifetimes. Coronene in PHC has a tremendously long halflife for phosphorescence and even for fluorescence (though not as long). Max Zander did some studies of coronene and hexabenzicoronene lifetimes in inert matrices. In crystals of coronene and other PAHs, the lifetimes are very, very short and the quantum efficiency drops – energy is lost through interactions between layers.
You are one of the few who has a copy of the book. It, unfortunately, only sold modestly.
Fetz the chemist
In the book I do mention an interesting perylene fact. If you make the carbocation, it is a very intense blood red. Quite a spectral shift, huh?
Fetz the chemist
So perylene itself is actually soluble? Shocking! The dianhydride is totally brickdust.
Solvation is the old likes attract thing. Perylene is soluble is non-polar solvents like hexane, aromatic ones like toluene, and slightly polar ones like dichloromethane, acetone, and ethyl acetate. I’d guess the polar derivatives go into acetonitrile, methanol, and other polar solvents, maybe even into water.
Fetz the chemist
So, now the real question is: Wat happens when you drink it?
it’s a suspected carcinogen, like many PAHs of its size. So I wouldn’t.
The solvent is 99+ % of your concern. Perylene is one of the PAHs that shows little biological activity. Some old literature shows a weak carcinogenicity, but that was most likely due to impurities in the perylene. PAHs used to be isolated from coal tar, so a lot of old data is the trace impurities (in this case, most likely its isomer benzo[a]pyrene).
Fetz the chemist
i love fluorescence!
siiiigh! So pretty!
One of my labmates used to work on functionalizing PDI’s. EVERYTHING he touched turned red and fluoresced. I made polymers that fluoresced green. Even took a video once. We just needed some one to come up with the blue.
Nichia makes some kickass 365nm LEDs. I’ve been playing with some of their 3 W monsters. Definitely not something you want to stare at. But fun for fluorescence. I built a little box with a piece of polycarbonate to block the UV with a couple of these guys for illumination. The smaller ones are nice to have in the lab, built into a ball-point pen case.
Nichia makes you sign a waiver before they will sell you these…
Intrinsic polycarbonate does NOT block 365 nm. If you have Uvex, etc., have a fiducial sample inside and quarterly check for continued UV blockage. Photo-Fries rearrangement! In a past employ I occasionally snuggled to a KW microwave-pumped 254 nm UV lamp. Turn on the rig, turn off the lights, walk around with sheets of Day-Glo paper. Grab some aluminum foil.
http://www.fresneltech.com/graphs/polycarbonate_graph.html
intrinsic polycarbonate
I used to play with ring lithiation of 1,1′-binaphtyl (just the parent hydrocarbon, you use tBuLi+KOtBu Schlosser superbase) and perylenes were our enemy: You could see yellow+fluorescent on column = bad news. 1,1′-binaphtyl loves to go to perylene, upon mixing with with AlCl3 or with Na / Li metal (the burgundy radical anion of binaphtyl turns into deep green radical anion of perylene)
I have a UV-Vis spectrometer that will hold big samples, so I just tried my piece of polycarbonate. It cuts off at around 400nm. It’s hard to tell exactly where the cutoff is in Al’s graph, but it’s prudent to be certain, since UV exposure of eyeballs can cause all sorts of nastiness. Wikipedia’s article on polycarbonate suggests it cuts off at 400nm, but still, since I was going to be staring at the thing, I tested it first.
Tech data from the supplier can tell, too, if you don’t have a UV Vis. Rodeca, for instance, co-extrudes a UV protectant layer that cuts off all UV below 380nm.
As far as UV exposure and UV cutoff, you have to remember that UV exposure is based on transmittance, not absorbance. UV cutoff is arbitrarily set as the wavelength where 1.0000 absorbance units occurs. This is still a huge amount of transmitted light to be exposed to.
I have not looked at medical studies on UV exposure for eye damage, but even 10 % transmittance would seem to be pretty bad.
Fetz the chemist
I think I’m not impressed anymore.
there are prettier molecules out there, but none as simple as this one. (what on earth is that stuff in your last post?)
Yeah, I don’t blame you…you win.
For now, at least. We’ll one-up you later.
I propose a science rave. The biophysicists/geneticists can provide the glowing kittens, bacteria, and plants. (Fluorescent proteins are up to about 15 different colors now, plus firefly luciferase). The chemists can bring all of their prettiest compounds…
I obtained perylene occasionally and did not know what is that in the beginning. Fluorescence was, as written in this article, huge and visible with usual lamps! So I run to mass spec people to check what is that. Next day I found beatiful picture in wikipedia with exactly the same fluorescence
. Just that the method which yeilded me perylene is possibly most complicated of all known ones and only insane chemist will ever try it again… at least for perylene 
I managed to obtain a wild mixture of PAH’s but it look like only perylene was soluble in ethanol and I got it in almost pure form. What is the rest of mixture is still a piece of mystery…
Perylene is the first condensate of naphthalene, if you do a pyrolysis or condensation by Fiedel-Crafts. Other isomers, two benzofluoranthene isomers, also are made, but fluoresce at much lower wavelengths. If this is what you did, then the know trimer is “terrylene (tribenzo’de,kl,rst]pentaphene), a red PAH with green fluorescence that should extract with dichloromethane. Xylene or chlorobenzene extraction ought to give you some of the fourth-mer, quatterylene, a green PAH of eleven rings, plus other isomers.
No it was different method. I started from fullerenes
Interesting in that A group at Leeds in the 90s pyrolized naphthalene and ended up wit C60 through condensation.
Almost any organic material after rapid pyrolisis gives little of fullerenes. Now insane chemists like me go back: we cracked fullerenes on large pieces under hydrogen pressure but mixtures are very complex: we know that large fragments preserved (MS) but so far have not separated mixtures on individual materials. I have several samples which are waiting for right hands to do this job…
Reaction of Hydrogen Gas with C60 at Elevated Pressure and Temperature: Hydrogenation and Cage Fragmentation
Talyzin, A. V.; Tsybin, Y. O.; Purcell, J. M.; Schaub, T. M.; Shulga, Y. M.; Noreus, D.; Sato, T.; Dzwilewski, A.; Sundqvist, B.; Marshall, A. G.
J. Phys. Chem. A.; (Article); 2006; 110(27); 8528-8534
See figure 9 there for MS with fullerene fragments.
C60 does not seem to behave like an aromatic molecule in hydrogenation. The pi bonds react more like a series of conjugated alkene bonds. I’d be interested in seeing if the hydrogenation and cracking of C60 looks like that, more of an unzipping of the seems into constituent bits. Larry Scott, Roger Taylor, and others have done a lot of syntheses of these semi-fullerene type PAHs.
The analysis ought to be relatively easy. If I had an HPLC to do it on, I would, but I can tell you how to. I even know of someone to approach for a collaboration who has a HPLC-UV-MS system and does large PAHs.
Hi, could anyone tell me how perylene reacts in electrophilic substitutions, does the electron density move into the central ring, or is it more like two seperate naphthalene units, could you show me the canonical forms. and why does perylene react predominantly at the 3 position? thanks lou
we’re not here to do your homework for you.