From chemistry-request _-at-_)server.ccl.net Tue Mar 4 16:15:43 2003 Received: from mail.uvigo.es ([193.146.32.91]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id h24LFhR05727 for ; Tue, 4 Mar 2003 16:15:43 -0500 Received: from mail.uvigo.es (localhost [127.0.0.1]) by mail.uvigo.es (8.12.8/8.12.1) with ESMTP id h24LFhEZ021707 for ; Tue, 4 Mar 2003 22:15:43 +0100 Received: from correo.uvigo.es (correo.uvigo.es [193.146.32.68]) by mail.uvigo.es (8.12.8/8.12.1) with ESMTP id h24LFd7E021702 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NOT) for ; Tue, 4 Mar 2003 22:15:39 +0100 Received: from correo.uvigo.es (localhost [127.0.0.1]) by correo.uvigo.es (8.12.8/8.12.5) with ESMTP id h24LFcn0011109 for ; Tue, 4 Mar 2003 22:15:38 +0100 Received: from correo (correo [193.146.32.68]) by correo.uvigo.es (8.12.8/8.12.5) with ESMTP id h24LFYUf011100 for ; Tue, 4 Mar 2003 22:15:34 +0100 Date: Tue, 4 Mar 2003 22:15:34 +0100 (CET) From: "Silva Lopez; Carlos" X-X-Sender: To: Subject: NBO Analysis Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from QUOTED-PRINTABLE to 8bit by server.ccl.net id h24LFhR05728 Hello CCLers! I have done a NBO analysis of a transition structure were a sigma bond is being broken. The problem arises when check the orbital structure, there is still a pi bond where the sigma bond is already broken. Could it mean there is a certain aromaticity in that TS and pi electrons are still creating a "current" despite of the big bond distances. Is there any other point of view (with chemistry sense, not mathematical formulation of anything non graspable)? Thanks _-_-_-_-_-_-_-_-_-_-_-_- Carlos Silva López Dpto. Química Orgánica Universidade de Vigo Phone num: 0034 986812226 -_-_-_-_-_-_-_-_-_-_-_-_