From owner-chemistry@ccl.net Sun Mar 24 13:18:26 1996 Received: from bedrock.ccl.net for owner-chemistry@ccl.net by www.ccl.net (8.7.1/950822.1) id NAA18646; Sun, 24 Mar 1996 13:12:27 -0500 (EST) Received: from uucp.intac.com for benisch@turnaround.com by bedrock.ccl.net (8.7.1/950822.1) id NAA21167; Sun, 24 Mar 1996 13:12:26 -0500 (EST) Received: from turnaround.com (magestic@localhost) by uucp.intac.com (8.7.1/8.6.5) with UUCP id MAA16127 for CHEMISTRY@ccl.net; Sun, 24 Mar 1996 12:57:23 -0500 (EST) X-Authentication-Warning: uucp.intac.com: magestic set sender to turnaround.com!benisch using -f From: benisch@turnaround.com (Jean Benisch) Reply-To: benisch@turnaround.com To: CHEMISTRY@ccl.net Subject: Source for chemicals & manufacturers Date: 24 Mar 1996 12:43:58 GMT Message-Id: <1422651358.13718452@turnaround.com> Organization: The Turnaround Team, Inc. Free new chemical resource has been posted on the World Wide Web called ChemExpo at http://www.chemexpo.com. ChemExpo is the chemical industry's source for over 20,000 chemicals; the latest news, chemical profiles, and business briefs; chemical products and services classifieds, forums, a calendar of events; a business card exchange and a column on people and jobs. ChemExpo's Show Floor searches over 2,000 company sources for specialty and fine chemicals, intermediates, petro and rubber chemicals, plastics, coatings, gases, synthetics, solvents, fertilizers, inorganics, plant equipment, custom processing and contract manufacturing. -- ================================================================= Jean Benisch | jb@turnaround.com | Vice President, |-------------------------------------| New Marketing Research | | The Turnaround Team, Inc. | 908.654.7117 (voice) | 123 South Avenue East | 908.654.5318 (Fax) | Westfield, NJ 07090-1454 | http://www.turnaround.com/ | ================================================================= From elewars@alchemy.chem.utoronto.ca Sun Mar 24 16:18:29 1996 Received: from alchemy.chem.utoronto.ca for elewars@alchemy.chem.utoronto.ca by www.ccl.net (8.7.1/950822.1) id PAA19509; Sun, 24 Mar 1996 15:34:23 -0500 (EST) Received: (from elewars@localhost) by alchemy.chem.utoronto.ca (8.7.4/8.7.3) id PAA12137 for chemistry@www.ccl.net; Sun, 24 Mar 1996 15:34:24 -0500 (EST) Date: Sun, 24 Mar 1996 15:34:24 -0500 (EST) From: "E. Lewars" Message-Id: <199603242034.PAA12137@alchemy.chem.utoronto.ca> To: chemistry@www.ccl.net Subject: REFS TO KINETICS/STRUCTURE 1996 March24 Hello, Here are two refs relevant to the relationship of structure to kinetics, a recent question on the Net. The matter is connected to the Hammond postulate and the Bell-Evans_Polanyi principle: General review: W. P. Jencks, Chem Rev, _85_, 511-527 (1985). Beta cleavage of radicals and structure: M-S Lee, D. A. Hrovat, W. T. Borden, J Am Chem Soc, _117_, 10353-10357 (1995). ============ E. Lewars ===== From elewars@alchemy.chem.utoronto.ca Sun Mar 24 17:18:29 1996 Received: from alchemy.chem.utoronto.ca for elewars@alchemy.chem.utoronto.ca by www.ccl.net (8.7.1/950822.1) id PAA19499; Sun, 24 Mar 1996 15:33:32 -0500 (EST) Received: (from elewars@localhost) by alchemy.chem.utoronto.ca (8.7.4/8.7.3) id PAA12119 for chemistry@www.ccl.net; Sun, 24 Mar 1996 15:33:19 -0500 (EST) Date: Sun, 24 Mar 1996 15:33:19 -0500 (EST) From: "E. Lewars" Message-Id: <199603242033.PAA12119@alchemy.chem.utoronto.ca> To: chemistry@www.ccl.net Subject: SINGLET DIRADICAL CALCULATINS__QUESTION 1996 March 24 Hello, I have a question about calc's involving SINGLET diradicals. Consider for example the ring-opening of tetrahedrane, Td (CH)4: H H H H | H / | \ / C \ / C C C/. / \ C . / / | \ | / . \ ---> | / . = H--C | C--H C ------- C C-----C \ | / / \ / \ C H H H H | 1 2 H singlet diradical: each of the two tricoordinate C's has one unpaired electron and the diradical has a multiplicity of 1, not 3, i.e the unpaired electrons have opposite spins Suppose one wants to find the activation energy and the reaction energy (i.e E_transition state - E_1, and E_2 - E_1). Then (1) What is the lowest-level calc that will give meaningful (not necessarily quantitatively good) results? (2) What level of calc is needed to get quantitatively reliable results? In particular, how can one calculate the geometry and energy of a singlet diradical like 2 (I presume the transition state between 1 and 2 can be handled by the same technique one applies to 2, provided of course one can find the TS, and that 1, 2 and the TS must all be treated by the same method if the relative energies are to be calc)? References would be very much appreciated. E. Lewars From owner-chemistry@ccl.net Sun Mar 24 22:18:31 1996 Received: from bedrock.ccl.net for owner-chemistry@ccl.net by www.ccl.net (8.7.1/950822.1) id WAA20961; Sun, 24 Mar 1996 22:02:10 -0500 (EST) Received: from gate.sinica.edu.tw for ccchuang@gate.sinica.edu.tw by bedrock.ccl.net (8.7.1/950822.1) id WAA25387; Sun, 24 Mar 1996 22:02:04 -0500 (EST) Received: by gate.sinica.edu.tw (5.x/SMI-SVR4) id AA19674; Mon, 25 Mar 1996 11:02:24 +0800 Date: Mon, 25 Mar 1996 11:02:22 +0800 (CST) From: Chyh-chong Chuang To: chemistry@ccl.net Cc: str-nmr@net.bio.net Subject: quantize the purity of a N-15 labeled amino acid Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Dear Netters: We had a N-15 labeled amino acid, and we wish to know to purity of the N-15 labeled amino acid (relative to N-14 a.a.). We plan to use nmr and mass to do so. The problems are: 1. when use nmr, like we can use in 1H-nmr, there must be a internal standard N-15 peak for correlation. What kinds of the standard could be used? 2. If use mass, which kind of mass could be used to quantize a peak? Or any other alternate could do so? Any comment will be great appreciated. ccchuang ============================================ Chyh-Chong Chuang Institude of Biological Chemistry, Academia Sinica,Taipei, Taiwan -------------------------------------------- Phone: 886-2-7858981 ext 7091 Fax: 886-2-7883473 E-Mail: ccchuang@gate.sinica.edu.tw ============================================