From owner-chemistry@ccl.net Tue Sep 1 08:04:01 2009 From: "Peter Bladon p.bladon**strath.ac.uk" To: CCL Subject: CCL: Generating enantiomers Message-Id: <-40141-090901072044-20676-ov8zyDGw+p7SJkV9dgawtA^_^server.ccl.net> X-Original-From: Peter Bladon Content-Language: en-US Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="us-ascii" Date: Tue, 1 Sep 2009 11:38:41 +0100 MIME-Version: 1.0 Sent to CCL by: Peter Bladon [p.bladon_._strath.ac.uk] Dear Thomas, Any good modelling package will have a tool for converting a structure into= its enantiomer. But in the absence a of such a tool you can use an editor to change the sig= ns of all of the (say) x coordinates. This operation will cause the structure to be reflecte= d in the YZ plane Similarly changing the signs of the y coordinates will cause reflection in = the XZ plane, and changing the signs of all the z coordinates will cause reflection in the XY= plane. If you change the signs of ALL the coordinates, this gives you inversion of= the structure about the origin. All this is easy. If what what you want is the generation of diastereoisom= ers, that is another matter. I do not know of a general method for doing this. I can think of s= ituations, where if you were to invert one chiral centre in a structure with two (or more) chir= al centres, you could end up with a sterically crowded structure. In these circumstances you woul= d need to follow the inversion with some form of energy minimization process. One way of app= roaching this problem, is to cut the structure into separate parts, each with one chiral = center, work on the parts to effect inversion as needed, and then to join them up again. The program INTERCHEM (http://www.interprobe.co.uk) has all the simple inve= rsion methods built in, as well as a lot of other useful tools for investigating stereoch= emistry. Hope this helps Cheers Peter Bladon ________________________________________ > From: owner-chemistry+cbas25=3D=3Dstrath.ac.uk- -ccl.net [owner-chemistry+cba= s25=3D=3Dstrath.ac.uk- -ccl.net] On Behalf Of Dipl.-Ing. Thomas Mitterfellner= thomas.mitterfellner^^^tugraz.at [owner-chemistry- -ccl.net] Sent: Monday, August 31, 2009 4:32 PM To: Bladon, Peter Subject: CCL: Generating enantiomers Sent to CCL by: "Dipl.-Ing. Thomas Mitterfellner" [thomas.mitterfellner]*[t= ugraz.at] Hello! Does anyone know of a program/tool for generating an enantiomer of a given structure (xyz, mol2, etc.)? Thank you, Thomas -=3D This is automatically added to each message by the mailing script =3D-http://www.ccl.net/cgi-bin/ccl/send_ccl_messagehttp://www.ccl.net/chemistry/sub_unsub.shtmlhttp://www.ccl.net/spammers.txt