From owner-chemistry@ccl.net Sun Sep 23 10:18:00 2012 From: "Alexandre Borrel alexandre.borrel*_*univ-paris-diderot.fr" To: CCL Subject: CCL: Statistical study of weak bonds in chemical compounds Message-Id: <-47651-120922051515-17633-oRX/Z90C31m27zPSkQ0Tgw _ server.ccl.net> X-Original-From: "Alexandre Borrel" Date: Sat, 22 Sep 2012 05:15:14 -0400 Sent to CCL by: "Alexandre Borrel" [alexandre.borrel _ univ-paris-diderot.fr] Dear Members, We would like to do a statistical study of weak bonds in chemical compounds. We are looking for data lengths and angles of hydrogen bonds X-H...N in first, secondary and tertiary amines. 1. Can you suggest references of publications mentioning that ? 2. Have you an idea of queries to retrieve in the Cambridge CSD bank the compounds with such bonding and locating the corresponding X,H,N atoms in the connection tables ? Thank you very much. Best regards, Alexandre Borrel. ----------------------------------------------- BORREL Alexandre PhD student University of Paris Diderot From owner-chemistry@ccl.net Sun Sep 23 13:23:01 2012 From: "Steve Williams willsd]![appstate.edu" To: CCL Subject: CCL: Statistical study of weak bonds in chemical compounds Message-Id: <-47652-120923130539-10100-i+vdKBcXXsk6baMBtw2oSg_-_server.ccl.net> X-Original-From: Steve Williams Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=us-ascii Date: Sun, 23 Sep 2012 13:03:17 -0400 Mime-Version: 1.0 (1.0) Sent to CCL by: Steve Williams [willsd%%appstate.edu] CSD query may not give useful results even if it is well formulated. Nearly all of the structures in the CSD are X-ray diffraction structures. Since X-ray scattering power increases with electron density, and since the electron density of H atoms must be very low, X-ray methods are rather poor at locating H atom nuclear positions. There MAY be a few neutron diffraction structures in the CSD that will have the x-h-n motif that you seek, but if so there may not be very many of these. Steve Williams Sent from my iPad On Sep 22, 2012, at 5:15 AM, "Alexandre Borrel alexandre.borrel*_*univ-paris-diderot.fr" wrote: > > Sent to CCL by: "Alexandre Borrel" [alexandre.borrel _ univ-paris-diderot.fr] > Dear Members, > > We would like to do a statistical study of weak bonds in chemical compounds. > We are looking for data lengths and angles of hydrogen bonds X-H...N in first, secondary and tertiary amines. > 1. Can you suggest references of publications mentioning that ? > 2. Have you an idea of queries to retrieve in the Cambridge CSD bank the compounds with such bonding and locating the corresponding X,H,N atoms in the connection tables ? > > Thank you very much. > > Best regards, > > Alexandre Borrel. > > ----------------------------------------------- > BORREL Alexandre > PhD student University of Paris Diderot> >