From chemistry-request@ccl.net Wed Nov 19 14:18:41 2003 Received: from Lilly.com (inet.d48.lilly.com [40.33.1.1]) by server.ccl.net (8.12.8/8.12.8) with ESMTP id hAJJI8RW009582; Wed, 19 Nov 2003 14:18:08 -0500 Received: from LILLY.COM ([40.25.2.46]) by INET.D48.LILLY.COM (PMDF V6.1-1 #30673) with ESMTP id <01L37W3OXC5200POUE!at!INET.D48.LILLY.COM>; Wed, 19 Nov 2003 14:18:07 -0500 (EST) Received: from mc1usmail8.am.lilly.com (mc1usmail8.AM.LILLY.COM [40.1.137.40]) by CLAVIN.D51.LILLY.COM (PMDF V6.1-1 #30673) with ESMTP id <01L37W3OG1G200HXWO!at!CLAVIN.D51.LILLY.COM>; Wed, 19 Nov 2003 14:18:06 -0500 (EST) Content-return: prohibited Date: Wed, 19 Nov 2003 14:17:33 -0500 From: ERICKSON_JON_A!at!Lilly.com Subject: Re: CCL:imaginary frequencies in cycloaddition's TS To: Alessandro Contini Cc: chemistry!at!ccl.net, Computational Chemistry List Message-id: MIME-version: 1.0 X-Mailer: Lotus Notes Release 5.0.4a July 24, 2000 Content-type: multipart/alternative; boundary="=_alternative 006A017805256DE3_=" X-MIMETrack: Serialize by Router on USMAIL8/AM/LLY(Release 6.0.2CF2|July 23, 2003) at 11/19/2003 02:17:36 PM, Serialize complete at 11/19/2003 02:17:36 PM X-Spam-Status: No, hits=4.5 required=7.0 tests=FROM_NO_LOWER,HTML_10_20,HTML_MESSAGE,NO_REAL_NAME version=2.55 X-Spam-Level: **** X-Spam-Checker-Version: SpamAssassin 2.55 (1.174.2.19-2003-05-19-exp) This is a multipart message in MIME format. --=_alternative 006A017805256DE3_= Content-Type: text/plain; charset="us-ascii" Allessandro, We tried to address the degree of 'synchronicity' (I was a Sting/Police fan at the time :-) of some proton-transfer reactions ~10 years ago by comparing the degree of bond-lengthening of the TS vs. the reactants. See: Erickson and Kahn, JACS, 1994, 116, 6271. Cheers, Jon ----------------------------------------------------------------------------------- Jon Erickson, PhD.; Computational Sciences, DCR&T Lilly Research Laboratories, Indianapolis, IN 46285 (317)433-2323, (317)276-6545 (FAX), jae!at!lilly.com ----------------------------------------------------------------------------------- Alessandro Contini Sent by: Computational Chemistry List 11/17/2003 04:35 AM To: chemistry!at!ccl.net cc: Subject: CCL:imaginary frequencies in cycloaddition's TS Hi, This could be a naive question, but I'd like to ask if is it possible to state if a cycloaddition reaction proceeds by a syncronous or asyncronous mechanism by visual inspection of the TS' imaginary frequency. Any suggestion or litt. ref. will be appreciated. Thanks a lot Alessandro Alessandro Contini, Ph.D. Istituto di Chimica Organica "Alessandro Marchesini" Universit` degli Studi di Milano, Facolt` di Farmacia Via Venezian, 21 20133 Milano Tel. +390250314480 Fax. +390250314476 e-mail alessandro.contini!at!unimi.it -= This is automatically added to each message by the mailing script =- To send e-mail to subscribers of CCL put the string CCL: on your Subject: line and send your message to: CHEMISTRY!at!ccl.net Send your subscription/unsubscription requests to: CHEMISTRY-REQUEST!at!ccl.net HOME Page: http://www.ccl.net | Jobs Page: http://www.ccl.net/jobs If your mail is bouncing from CCL.NET domain send it to the maintainer: Jan Labanowski, jkl!at!ccl.net (read about it on CCL Home Page) -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ --=_alternative 006A017805256DE3_= Content-Type: text/html; charset="us-ascii"
Allessandro,

We tried to address the degree of 'synchronicity' (I was a Sting/Police fan at the time :-) of some proton-transfer reactions ~10 years ago by comparing the degree of bond-lengthening of the TS vs. the reactants.  See: Erickson and Kahn, JACS, 1994, 116, 6271.

Cheers,
Jon
 -----------------------------------------------------------------------------------
Jon Erickson, PhD.; Computational Sciences, DCR&T
Lilly Research Laboratories, Indianapolis, IN 46285
(317)433-2323, (317)276-6545 (FAX), jae!at!lilly.com
-----------------------------------------------------------------------------------



Alessandro Contini <alessandro.contini!at!unimi.it>
Sent by: Computational Chemistry List <chemistry-request!at!ccl.net>

11/17/2003 04:35 AM

       
        To:        chemistry!at!ccl.net
        cc:        
        Subject:        CCL:imaginary frequencies in cycloaddition's TS



Hi,
This could be a naive question, but I'd like to ask if is it possible to
state if a cycloaddition reaction proceeds by a syncronous or asyncronous
mechanism by visual inspection of the TS' imaginary frequency.
Any suggestion or litt. ref. will be appreciated.

Thanks a lot

Alessandro

Alessandro Contini, Ph.D.
Istituto di Chimica Organica "Alessandro Marchesini"
Universit` degli Studi di Milano, Facolt` di Farmacia
Via Venezian, 21 20133 Milano
Tel. +390250314480 Fax. +390250314476
e-mail alessandro.contini!at!unimi.it




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