pKa of perylene derivatives

Is there anyway I can estimate pKa without doing titration? My compounds will aggregate when they are close to their pKa values. I have attached file of my compound with this message. But if you cannot see it, they are perylene derivatives with the sidechains. I may just want to know the pKa of the side chains. I wonder about the pKa of the tris side chain and the piperidine side chain. Does anyone know the Pka of N-alkyl piperidine?





Wirote

Hi Wirote,





I have calculated the pKa of the side chains.








P-GLU : pKa of carboxyl groups : 3.24, 3.70, 4.10, 4.50;








P-HIS: pKa of carboxyl groups : 3.40, 4.0;


pKa of pyrrolydine nitrogens: 6.83 (base) 6.23 (base),


12.64(acid) , 13.24 (acid);








PIPER : pKa of tert. amines: 8.1, 8.70;





P-TRIS: pKa of amines: 3.67, 4.27, 9.17, 9.59, 9.95, 10.37





You can try pKa calculator at this site:


http://www.chemaxon.com/demosite/marvin/index.html








Best wishes


Jozsi

Dear Jozsi,





Thank you for your help. When I got the message the other day, I tried to find a reply botton and I could not. I wonder whether because I was a guest then. I have just signed up for academics package. Anyway, the other day I posted a wrong structure of P-HIS. I have tried to go to the site you suggested but I just don't know how to begin. Do I have to download software from somewhere? I have attach the right structure this time, I will be really grateful if you may calculate it for me.





By the way, I am writing a research article right now. I'll actually use the calculation from you to interpret my data. What is the appropriate way to quote your software?





Sincerely,


Wirote Tuntiwechapikul, Ph.D.

Quote:

I have tried to go to the site you suggested but I just don't know how to begin. Do I have to download software from somewhere?

If you don't want to waste your time with downloading and installing Marvin, you can use the Marvin applets on the ChemAxon site.


Try these examples:


http://www.chemaxon.com/marvin/doc/dev/index.html#examples


Java is required for running Marvin. If Java has not installed yet to your machine, Marvin applets can not start. Internet Explorer and other browsers under Windows can download and install Java automatically, if they detect that there is no Java on the machine. Otherwise you have to download and install Java, manually:


http://java.sun.com/j2se/1.5.0/download.jsp





MarvinSketch and MarvinView can run also as desktop applications. You can install Marvin applications by a platform specific installer. You can download the installers from here.


http://www.chemaxon.com/marvin/do-download.html#beans

If you choose to install Marvin Beans, I suggest to select the installer that includes Java: http://www.chemaxon.com/marvin/do-download.html#enduser

We would like for your to cite our software in your article, like this:

Product, version #.#, ChemAxon, Budapest, Hungary. www.chemaxon.com/products.html