Which functional groups would form hydrogen bonds with neighbouring molecules?

1 Answer
Truong-Son N.
Sep 16, 2015

Any functional group that has these can hydrogen-bond with neighboring molecules:

  • "C"="O" (hydrogen-bond acceptor)
  • "C"-"O"-"C" (hydrogen-bond acceptor) [some]
  • "C"-"NR"" (hydrogen-bond acceptor)
  • "C"="NR" (hydrogen-bond acceptor)
  • "C"-"OH" (hydrogen-bond donor AND acceptor)
  • "C"-"NH" (hydrogen-bond donor AND acceptor)
  • "C"="NH" (hydrogen-bond acceptor AND donor)
  • "C"-="N" (hydrogen-bond acceptor)

Any lone electron pairs present on the oxygen or nitrogen in the carbonyl, ether, the hydroxyl, the amino, the imino, and the nitrile groups above are hydrogen-bond accepting, while the hydrogens on the hydroxyl, amino, and imino groups are hydrogen-bond donating.

That means these parts of these functional groups count:

  • ketone ("C"="O")
  • aldehyde ("C"="O")
  • alcohol ("C"-"OH")
  • carboxylic acid ("C"="O", "C"-"OH")
  • ester ("C"="O", "C"-"O"-"C")
  • amine (-"N"-"H", -"N"-"R")
  • imine (="N"-"H", ="N"-"R")
  • amide ("C"="O", -"N"-"H", -"N"-"R")
  • imide ("C"="O", ="N"-"H", ="N"-"R")
  • nitrile ("C"-="N")
  • amino acid (amine + carboxylic acid)

And any other functional groups that contain those.

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