Wittig reagent / pka bug
I tried to calculate the pKa of the Wittig reagent, but only one form gives me the pKa of the reactive Carbon, the phosphorane form, whereas the ylide form (frequently used by chemists to draw the reaction) does not... and the other pKas change (even if not relevant). Furthermore, the ylide form is the first resonance form the plugin gives me!
I'm surprised at your non-response... Maybe I wasn't clear in my explanations?
No worry though, there is no urgency, I came across this problem but it's not life-threatening ;-)
I'm sorry not inform you about the fixing of this bug.
I'm working on the solution on this problem. The pKa calculation will be availabe for this resonance structure in the next patch release.
Hi, I have some more questions here.
Does I see it right? The "pKa" values above are in reality the pKa of the conjugate acid ?
1) So I tried to calculate the pKa for this conjugate acid, see screenshot. But here is also no value for the alfa atom of the ethyl group. Why?
2) And the values for the three phenyl groups are different, even for the equivalent ortho- and meta-positions.
What are the options for the calculations above? I my case these are: macro / dynamic, min -30 / max 40, 298 K.
Oh great, I'm glad I made a point. Thank you for the answer.
Hans-Ulrich, I think your follow-up question is a corollary...
"... a corollary... "
Does this also concern the second question about the phenylgroup results ?
you're right, not the 2nd...
I tried it with 5.2.0, it still makes the same mistake, and it takes the wrong tautomer: the C- is protonated instead of makeing a double bond between C and P...
|2) And the values for the three phenyl groups are different, even for the equivalent ortho- and meta-positions. |
May be you adjusted the "macro pKa mode", this is why you obtained diffrenet pKa values.
I have adjusted the "micro pKa mode" on the attached figure.
|I tried it with 5.2.0, it still makes the same |
mistake, and it takes the wrong tautomer: the C- is protonated instead
of makeing a double bond between C and P...
These bug fixed modifications were added to the 5.2.1 version that will be released in april.