Dear Ed and All, Happy new Year!!
According to Desiraju and Steiner in their book "The Weak Hydrogen Bond" O/N-H...Cl-C bonds occur rarely in the crystal structure (probably they are referring to small molecule structures). But they site several examples where such interaction is intramolecular, typically formed because the donor cannot find a stronger acceptor. In your case, if the Histine N-H does not have a suitable acceptor, it may settle down with chlorine. With best wishes Anthony On Tue, 30 Dec 2008 13:05:55 -0500, Edward A. Berry wrote > Dear all, > Is it possible for a Cl atom attached to an aromatic ring to > accept an H-bond from His NE2? > I'm modeling a low-resolution ligand structure and my favorite fit > shows such a bond, but it is possible the ring is flipped and > an OH or -C=O on the other side of the ring actually make the H-bond. > > Thanks, > Ed ------------------------------------------------- Anthony Addlagatta, Ph.D. Ramanujan Fellow and Senior Scientist Center for Chemical Biology Indian Institute of Chemical Technology [IICT] Tarnaka, Hyderabad- 500007, INDIA Tel:+91-40-27191583 Url: http://www.iictindia.org/zacb/Dr.%20Anthony.aspx
