Hydrogen bond donor count for primary amides?

User a11e9761d6

06-09-2013 21:24:39

Hi ChemAxon,

The donorCount chemical terms function returns 1 for a primary amide, while other calculators return two. It seems that both hydrogens on the nitrogen could participate in H-bonds.



User a11e9761d6

06-09-2013 21:55:04

Ah, I see: you are counting the heavy atoms that act as donors, not the number of H-bonds that can be formed.


User 851ac690a0

10-09-2013 23:49:31



Yes. The  distribution diagram of  an acetamide molecule  calculated with Marvin given below.  

The average donor hydrogen atom count "Don" and the average acceptor  lone pair count "Acc" plotted as function of the pH on the attached figure. The number of the donor site count is  2  "H" atoms. And there are 2  acceptors lone pair electron on the keto group.