>From jkl@ccl.net Wed May 28 00:36 EDT 1997 Received: from krakow.ccl.net for jkl@ccl.net by bedrock.ccl.net (8.8.3/950822.1) id AAA09511; Wed, 28 May 1997 00:36:02 -0400 (EDT) Received: for jkl@ccl.net by krakow.ccl.net (8.8.3/920428.1525) id AAA09273; Wed, 28 May 1997 00:36:02 -0400 (EDT) From: Jan Labanowski Date: Wed, 28 May 1997 00:36:02 -0400 (EDT) Message-Id: <199705280436.AAA09273@krakow.ccl.net> To: jkl@ccl.net Subject: From List Coordinator Cc: jkl@ccl.net Dear CCL Subscribers... First, the bad news... All job announcements which were sent to me between May 7 and May 27 were lost. Sometimes improvements backfire {:-(}, especially at 2am. Please RESEND the job announcements to me again (jkl@ccl.net), if you do not see them in the CCL archives. Some of you noticed that we have a new way of presenting jobs: http://www.ccl.net/cca/jobs/joblist.html and conferences: http://www.ccl.net/cca/info/conferencelist.html Then no news {:-)}... Sorry for being less attentive to the list lately. My student assistants are trying to keep it up as well as they can. We are working on major rehab of the list, on running it from different machines, and we still do not feel that we are ready to switch. Bear with us, please... And the known appeal: Please keep the CCL a valuable resource by asking good questions and giving good answers. And my thanks to all of you who use the list in this spirit. We will have some technical improvements at some point, but they will not change the contents of list exchanges (computers may win a chess game, but still cannot create knowledge...) and therefore, the quality of information which appears on the list will still be produced by humans... Jan Labanowski jkl@ccl.net From ep7@dent.okayama-u.ac.jp Wed May 28 01:45:10 1997 Received: from deews1.dent.okayama-u.ac.jp for ep7@dent.okayama-u.ac.jp by www.ccl.net (8.8.3/950822.1) id BAA15178; Wed, 28 May 1997 01:28:13 -0400 (EDT) From: Received: from [150.46.140.80] (yobou2.dent.okayama-u.ac.jp [150.46.140.80]) by deews1.dent.okayama-u.ac.jp (8.7.5+2.6Wbeta6/3.3W9) with SMTP id PAA29250 for ; Wed, 28 May 1997 15:30:07 +0900 (JST) Message-Id: <199705280630.PAA29250@deews1.dent.okayama-u.ac.jp> Date: Wed, 28 May 1997 14:33:41 +0900 To: CHEMISTRY@www.ccl.net Subject: =?ISO-2022-JP?B?GyRCI1MjQyNSI0YbKEI=?= MIME-Version: 1.0 Content-Type: text/plain; charset=iso-2022-jp X-Mailer: Eudora-J(1.3.8.5-J13) Hello, I would like to ask everybody for the energy of SCRF calculation in Gaussian 94. Energy in summary (final section) in Gaussian 94 is total energy include solvent energy ? Thank you. Masao Masamura Preventive Dentistry Okayama University Dental School Shikata-cho, 2-5-1 Okayama 700 Japan FAX: 81-86-225-3724 e-mail: ep7@dent.okayama-u.ac.jp From ccl@www.ccl.net Tue May 20 15:43:37 1997 Received: from bedrock.ccl.net for ccl@www.ccl.net by www.ccl.net (8.8.3/950822.1) id OAA28431; Tue, 20 May 1997 14:45:48 -0400 (EDT) Received: from pnl.gov for ma_thompson@ccmail.pnl.gov by bedrock.ccl.net (8.8.3/950822.1) id OAA03850; Tue, 20 May 1997 14:45:48 -0400 (EDT) Received: from pnlmse1.pnl.gov by pnl.gov (PMDF V4.3-13 #6012) id <01IJ3AXBMLF48Y5E9F@pnl.gov>; Tue, 20 May 1997 11:45:19 -0700 (PDT) Received: from ccmail.pnl.gov by pnlmse1.pnl.gov with SMTP (Microsoft Exchange Internet Mail Service Version 5.0.1457.7) id LDZKY2HB; Tue, 20 May 1997 11:45:15 -0700 Received: from ccMail by ccmail.pnl.gov (IMA Internet Exchange 2.1 Enterprise) id 0010F4A2; Tue, 20 May 97 11:45:12 -0700 Date: Tue, 20 May 1997 11:29:25 -0700 From: ma_thompson@ccmail.pnl.gov (MARK A THOMPSON) Subject: Argus software To: chemistry@ccl.net Message-id: <0010F4A2.@ccmail.pnl.gov> MIME-version: 1.0 Content-type: text/plain; charset=US-ASCII Content-description: cc:Mail note part Content-transfer-encoding: 7bit Announcement regarding Argus molecular modeling program ******************************************************* I am leaving Pacific National Laboratory. The Argus program will be taken over by the NWChem group at PNNL. The QM/MM capabilities within Argus are being incorporated into the NWChem suite of parallel software. I have given them permission to distribute Argus as part of NWChem in the future. The old version of Argus will continue to be distributed on the internet via anonymous ftp (pnlg.pnl.gov, in the argus directory). Thanks to all present users for your valuable comments and enthusiasm for using my program! It's been very fun. Mark Thompson Pacific Northwest National Laboratory Richland, WA. From cmral@mimose3.urz.uni-halle.de Wed May 21 13:43:48 1997 Received: from mlucom3.urz.uni-halle.de for cmral@mimose3.urz.uni-halle.de by www.ccl.net (8.8.3/950822.1) id MAA06789; Wed, 21 May 1997 12:48:57 -0400 (EDT) Received: from mimose2.urz.uni-halle.de by mlucom3.urz.uni-halle.de with Local SMTP (PP); Wed, 21 May 1997 18:48:01 +0200 Received: from mimose3.projekte.urz by mimose2.urz.uni-halle.de (5.0/SMI-SVR4) id AA04635; Wed, 21 May 1997 18:45:11 --100 Received: by mimose3.projekte.urz (5.0/SMI-SVR4) id AA06375; Wed, 21 May 1997 18:32:53 --100 Date: Wed, 21 May 1997 18:32:53 --100 From: cmral@mimose3.urz.uni-halle.de (Thomas Novak) Message-Id: <9705211632.AA06375@mimose3.projekte.urz> Subject: CCL: Looking for program Content-Type: text Apparently-To: CHEMISTRY@www.ccl.net Dear colleagues, in order to examine the reliability of the DFT-treatment, I've been looking for the most efficient way of performing some calculations on our catalyst models with highly sophisticated single reference post-HF methods, such as CCSD[T], CPF or MCPF. A system under investigation is f.i. cationic NiC9H15, consisting of 86 electrons within 246 basis functions. Which commercial program system should best be suitable of doing this large job regarding efficient consumption of cpu-time and storage space and possible restart facilities ? Any suggestions are highly appreciated. -- Thomas From ccl@www.ccl.net Wed May 21 16:57:22 1997 Received: from bedrock.ccl.net for ccl@www.ccl.net by www.ccl.net (8.8.3/950822.1) id QAA07859; Wed, 21 May 1997 16:02:15 -0400 (EDT) Received: from hrz-fserv7.hrz.uni-kassel.de for gdanitz@hrz-serv1.hrz.uni-kassel.de by bedrock.ccl.net (8.8.3/950822.1) id QAA28513; Wed, 21 May 1997 16:02:11 -0400 (EDT) Received: from hrz-serv1.hrz.uni-kassel.de (hrz-serv1.hrz.uni-kassel.de [141.51.192.30]) by hrz-fserv7.hrz.uni-kassel.de (8.8.5/8.8.5) with ESMTP id WAA50108 for ; Wed, 21 May 1997 22:02:10 +0200 Received: (from gdanitz@localhost) by hrz-serv1.hrz.uni-kassel.de (8.8.5/8.8.5) id WAA47919 for chemistry@ccl.net; Wed, 21 May 1997 22:02:10 +0200 From: Robert Gdanitz Message-Id: <199705212002.WAA47919@hrz-serv1.hrz.uni-kassel.de> Subject: Relativistic correction to De of N2. To: chemistry@ccl.net (Computational Chemistry List) Date: Wed, 21 May 1997 22:02:10 +0200 (MES) X-Mailer: ELM [version 2.4 PL24 PGP3 *ALPHA*] MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Dear CCLers! I wonder if anybody who uses a program able to treat relativistic and electron correlation effects simultaneously can compute for me the relativistic correc- tion to the dissociation energy of N2. According to the Cowan-Griffin approxi- mation in 1st order PT it should amount to ~0.1 kcal/mol, however, I have con- siderable difficulties to get consistent results and accurate literature values seem not to be available. The reason for me being interested in that number is that I am presently pre- paring a paper on calculating the spectroscopic constants of N2 with explicitely correlated CI methods and it looks as if I am indeed approaching 0.1 kcal/mol accuracy. Regards, Robert -- +-----+ Robert J. Gdanitz email: gdanitz@hrz.uni-kassel.de | GhK | Gesamthochschule Kassel Tel.: +(49) 561-804-4120 | | Fachbereich 18 (Physik) Fax: +(49) 561-804-4006 +-----+ D-34109 Kassel, Germany From szilagyi@indy.mars.vein.hu Wed May 21 18:03:20 1997 Received: from elod.vein.hu for szilagyi@indy.mars.vein.hu by www.ccl.net (8.8.3/950822.1) id QAA08112; Wed, 21 May 1997 16:48:27 -0400 (EDT) Received: by elod.vein.hu (5.65/DEC-Ultrix/4.3) id AA03699; Wed, 21 May 1997 22:47:42 +0200 Received: from szilagyi.io.vein.hu ([193.6.32.233]) by almos.vein.hu (5.x/SMI-SVR4) id AA05486; Wed, 21 May 1997 22:49:33 +0200 Message-Id: <33835F03.50FF@mm2.vein.hu> Date: Wed, 21 May 1997 22:45:55 +0200 From: "Robert K. Szilagyi" Reply-To: szilagyi@indy.mars.vein.hu Organization: Muller Lab., University of Veszprem, Hungary X-Mailer: Mozilla 3.01Gold (Win95; I) Mime-Version: 1.0 To: Jeffrey.Nauss@UC.Edu Cc: chemistry@www.ccl.net Subject: Re: CCL:Spartan: MM2 parameters problems References: <9705211137.ZM2398@beryllium.crs.uc.edu> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit > SPARTAN MECHANICS (MM2) PROGRAM: SGI/R4K Release 4.1 a2 > (Job run on ucmodl.che.uc.edu) > > test > > Missing angle parameter: 2 19 6 0 (2 1 13) > Dear Jeffrey, the bond angle parameter for an sp2 carbon - sp3 silicon - and an sp3 oxygen is missing. The zero means that this angle is not included in any ring system. You have now two choices. You should check the bibliography, collect the available structural information about the C-Si-O bond angle and then perform a parameter optimisation which normally may take months. The other way is to use the chemical analogy and you can try to guess the missing parameters. (There was a paper published by Dr. Dora Schnurr >from the Monsanto Co. in the J. Comp. Chem. 1992 about the "quasi quantitative" quess of missing parameters, but I think you do not have to use this method due to a lucky situation.) The parameter set of the Spartan can give some further information about the bonding for similar silicon compounds: Atom type Force Strain-free MM2 mnemonic Constant Angle numeric type C sp2 Si sp3 C sp3 0.40 110.2 2 19 1 C sp2 Si sp3 C sp2 0.60 109.5 2 19 2 C sp2 Si sp3 H 0.24 109.5 2 19 5 C sp2 Si sp3 Si sp3 0.40 110.2 2 19 19 Taking into account these figures, the force constant should be between 0.6 and 0.24 and the strain free bond angle should be about the ideal sp3 hybrisisation state. If I were you, I choose the 0.60 and 109.5 deg., since the bonding between an sp3 Si and an sp3 O with lone pairs is might be closest to the C sp2 Si sp3 Csp2 situation. Technically, you should edit the params.MM2 file and insert somewhere after the heading BEND (bond angle bending parameters) the line 2: BEND 2 19 6 0.60 109.50 0.0 0.0 0 1 1 1 0.45 109.47 109.51 109.50 0 ... ENDBEND Now, you can submit the MM2 job again and hopefully there will be no further problem. Good luck and let me know if you need further help! Best wishes, -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Robert K. Szilagyi Mueller Laboratory ph.d. student Dept. Organic Chemistry University of Veszprem szilagyi@mm2.vein.hu Veszprem, H-8201 POB. 158; Egyetem u. 10. Phone: +36 88 422022 extn. 395 HUNGARY Mobile: +36 20 461413 Fax: +36 88 427492 http://mm1.vein.hu/ ====================================================================== ********** All opinions are my own, NOT my employer's ! ********** ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ From toukie@zui.unizh.ch Thu May 22 04:43:57 1997 Received: from zzmkgtw.zzmk.unizh.ch for toukie@zui.unizh.ch by www.ccl.net (8.8.3/950822.1) id EAA10845; Thu, 22 May 1997 04:01:26 -0400 (EDT) Received: by zzmkgtw.zzmk.unizh.ch; (5.65v3.2/1.3/10May95) id AA01421; Thu, 22 May 1997 10:01:24 +0200 Message-Id: <1.5.4.32.19970522080328.006652d0@highdent.zzmk.unizh.ch> X-Sender: toukie@highdent.zzmk.unizh.ch (Unverified) X-Mailer: Windows Eudora Light Version 1.5.4 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Thu, 22 May 1997 10:03:28 +0200 To: chemistry@www.ccl.net From: "Hr. Dr. S. Shapiro" Subject: 2 unrelated questions Dear Colleagues; I have two quite unrelated questions for which perhaps some CCLers might be able to provide useful replies: Question 1: In order to obtain Mulliken partial atomic charges for some work in which we are engaged, I prepared a Z-matrix for the molecule p-tolylacetylene ("tolac.mop"), as follows: am1 nointer p-tolylacetylene C 0.000000 0 0.000000 0 0.000000 0 0 0 0 C 1.401729 0 0.000000 0 0.000000 0 1 0 0 C 1.399999 0 120.081459 0 0.000000 0 2 1 0 C 1.399809 0 120.056900 0 0.000000 0 3 2 1 C 1.399806 0 119.942001 0 0.000000 0 4 3 2 C 1.400006 0 120.056679 0 0.000000 0 5 4 3 C 1.312333 0 120.109207 0 180.000000 0 1 2 3 C 1.200200 0 179.891647 0 180.000000 0 7 1 2 H 1.103619 0 119.699532 0 180.000000 0 2 3 1 H 1.103127 0 119.972672 0 180.000000 0 3 2 1 H 1.103111 0 120.028992 0 180.000000 0 4 3 2 H 1.103127 0 119.970596 0 180.000000 0 5 4 3 H 1.103619 0 119.699341 0 180.000000 0 6 5 4 H 1.059943 0 180.000000 0 180.000000 0 8 7 1 When I tried running it in MOPAC 6.0, I got the following output: CALCULATION ABANDONED AT THIS POINT THREE ATOMS BEING USED TO DEFINE THE COORDINATES OF A FOURTH ATOM, WHOSE BOND-ANGLE IS NOT ZERO OR 180 DEGREEES, ARE IN AN ALMOST STRAIGHT LINE. THERE IS A HIGH PROBABILITY THAT THE COORDINATES OF THE ATOM WILL BE INCORRECT. THE FAULTY ATOM IS ATOM NUMBER 14 : : [some stuff omitted] : : CARTESIAN COORDINATES UP TO FAULTY ATOM I X Y Z 1 .00000 .00000 .00000 2 1.40173 .00000 .00000 3 2.10345 1.21144 .00000 4 1.40648 2.42540 .00000 5 .00667 2.42736 .00000 6 -.69623 1.21660 .00000 7 -.65833 -1.13526 .00000 8 -1.26237 -2.17238 .00000 9 1.95719 -.95365 .00000 10 3.20658 1.20934 .00000 11 1.95985 3.37966 .00000 12 -.54306 3.38375 .00000 13 -1.79982 1.22503 .00000 14 .00000 .00000 .00000 ATOMS 8, 7, AND 1 ARE WITHIN .0025 ANGSTROMS OF A STRAIGHT LINE Adding the keyword "geo-ok" didn't help. Does anyone know of a workaround to this so that I can obtain Mulliken partial atomic charges for the atoms of p-tolylacetylee using MOPAC? Question 2: I would like to know if there is some established quantitative measure of the "degree" of chirality. For example, consider the chiral molecules CR1R2R3R4, where in one case R1 = H, R2 = D, R3 = T, and R4 = F, whereas in another case R1 = H, R2 = naphthyl, R3 = n-octyl, and R4 = NO2. Whilst both molecules are chiral, it is clear that the structural variation when R1 = H, R2 = naphthyl, R3 = n-octyl, and R4 = NO2 makes this a "more" chiral molecule than when R1 = H, R2 = D, R3 = T, and R4 = F. But how to express in a quantitative fashion that the second chiral molecule is "more" chiral than the first? I thought that perhaps the RMS deviation between the two enantiomorphs of each of these chiral molecules might provide quantification of chirality. Does anyone have any further, possibly better, suggestions? Thanks in advance to all responders. Sincerely, S. Shapiro toukie@zui.unizh.ch From gadre@chem.unipune.ernet.in Thu May 22 07:07:12 1997 Received: from naveen.ncst.ernet.in for gadre@chem.unipune.ernet.in by www.ccl.net (8.8.3/950822.1) id FAA11219; Thu, 22 May 1997 05:52:09 -0400 (EDT) Received: from unipune.ernet.in (unipune.ernet.in [196.1.114.1]) by naveen.ncst.ernet.in (8.6.12/8.6.6) with ESMTP id PAA11780 for ; Thu, 22 May 1997 15:05:05 +0530 Received: from chem.unipune.ernet.in by unipune.ernet.in (8.8.5/UNIPUNE-MAILHUB(02.04.97)) id OAA04893; Thu, 22 May 1997 14:56:29 -0500 (GMT) Received: by chem.unipune.ernet.in (8.7.5/SMI-SVR4) id PAA03809; Thu, 22 May 1997 15:07:57 -0500 Date: Thu, 22 May 1997 15:07:57 -0500 From: gadre@chem.unipune.ernet.in (Prof. Shridhar R. Gadre) Message-Id: <199705222007.PAA03809@chem.unipune.ernet.in> To: CHEMISTRY@www.ccl.net Subject: ICCCRE second announcement XII International Conference on Computers in Chemical Research and Education (XII ICCCRE) SECOND ANNOUNCEMENT It is our pleasure to invite you to the XII International Conference on Computers in Chemical Research and Education (ICCCRE) which is being organised at University of Pune, India from January 5 to 9, 1998. We are happy to inform you that we have received excellent response from all over the world and many eminent scientists have agreed to participate in the conference. Some of the invited speakers who have already accepted our invitation are : Professor/Drs. A. L. Parrill-Baker, S.P. Bhattacharyya, C.J. Cramer, E.R. Davidson, M.J. Field, S.R. Gadre, F.A. Gianturco, K. Hirao, S. Iwata, R.S. Lamba, H.P. Luthi, P. Lykos, A.R. Moll, M. Marsili, C. Middlecamp, K. Raghavachari, M. Rami Reddy, A.P. Rendell, S. Ramasesha, H.F. Schaefer III, N. Sathyamurthy, J.J.P. Stewart, W. Torop, I.K. Ugi, R. Viswanathan, N. Yathindra, S.E. Yoo, M.C. Zerner et al. The list is still expanding ! The tentative program of the conference is given below. Date 9.00-12.00 13.00-15.00 15.30-18.00 Invited + Contributed Poster Session Invited + Contributed Lectures Lectures Jan 5 T1 P1 T2 Jan 6 T2 P2 T3 Jan 7 T3 P3 Excursion Jan 8 T4 P4 T5 Jan 9 T4 P5 T6 The topics listed above are as follows. T1 : Semi-Empirical, Ab initio and Density Functional Methods T2 : Electronic journals, Publishing, Conferencing and Networks T3 : Molecular modeling, Quantitative structure-Activity Relationship T4 : Computers in Chemical Education T5 : Artificial intelligence, Chemometrics, Neutral networks and their chemical applications T6 : New Algorithms and Techniques in computational chemistry and parallel computing P1 : Topics covered under T1. P2 : Topics under T3. P3 : Topics discussed in T2 and T5. P4 : Topics under T6. P5 : Topics covered in T4. On three days, there may be evening lectures from 19:30 to 20:30. *********************************************************************** Award Announcement : *********************************************************************** To commemorate the Golden Jubilee of India's Independence we are pleased to announce TWO prizes, one each in the category of contributed lectures and posters for the best presentation. ************************************************************************ Information on Abstracts : Abstracts for invited talks/contributory presentations/posters should be submitted not later than July 31, 1997 to Dr. Shridhar R. Gadre Department of Chemistry University of Pune Pune-411 007. (INDIA) fax : 0091-212-351728 e-mail : gadre@unipune.ernet.in The printed area must be contained within a rectangle of size 234 x 156 mm (9.2" x 6.1"). Top 50 mm should be used only for title and Authors' name/s and address/es. For title, a font size of 14 in bold face is recommended. The name and address may be done in font size 12. Abstract should be preferably written in MS WORD or Mac WORD software (1.5 line spacing) using Times font with a font size of 10. In case of unavailability of WORD the abstract may be written using any software. The abstract should fit in one A4 size page. References denoted by superscript numbers in the text and should be listed at the end of the text using standard Chemical Abstracts Source Service Index (CASSI) terminology, followed by YEAR, VOLUME AND PAGE. Please note that abstracts will be reproduced directly from the authors' originals and hence 2 copies should be mailed without folding the paper. A book of abstracts of all oral and poster contributions will be distributed at the meeting. The registration fees for the participants from abroad are : US$ 300 for non-students and US$ 150 for students. The registration fees should be paid before July 31, 1997. The late registration fees are US$ 400 (non students) and US$ 200 (students) only upto September 30, 1997. Equivalent amount in British pounds, Deutsche marks or Japanese yens or of course, Indian Rupees is also acceptable. The fees are non-refundable. The registration fees should be paid by demand-draft /banker's draft in the name of "The Registrar, University of Pune" payable at the State Bank of India, Pune. Payment is also acceptable by visa and master card. Please contact us for fuller details before effecting the payment. The current exchange rate is approximately Rs.36 per US$. Travel : The participants are requested to book their flight arriving at Mumbai (Bombay) International airport. There are some domestic connecting flights from Mumbai to Pune. You should try to get such connecting flight (if available) to reach Pune. Upon your arrival at Pune (domestic) airport, arrangements will be made to carry you upto your Hotel/conference site. For the participants who do not have connecting flights from Mumbai to Pune, special arrangements may be made to provide ground transportation upto Pune. Our volunteers will be available on the airport to receive you if you send us your arrival schedule in advance (at least 30 days before the conference). For further information on Pune University and Pune city, you may visit the web site http://www.unipune.ernet.in http://www.unc.edu/~pune For travel information around Pune you may visit http://iucaa.iucaa.ernet.in/~snk/place1.html http://iucaa.iucaa.ernet.in/~snk/place2.html For travel with in Maharashtra State visit web sites http://spiderman.bu.edu/misc/india/places/indiastates/maharashtra.html http://www.clemson:edu/~nsankar/india/states/maharashtra.html http://wwwvms.utexas.edu/~savkar/rashtra.html Weather in Pune The maximum and minimum temperatures in Pune in January are around 27 and 7 degrees Celsius respectively. Normally there are no rains around this time and relative humidity is normally less than 40%. Hotels : The accommodation is arranged in various hotels in Pune. Your room may be booked in any of the following hotels. Please tell us your two preferences and we shall be happy to do the room booking for you. All hotels accept credit cards( at least VISA and MASTER CARD ). 1. Hotel Span Executive ; Revenue Colony, Shivaji Nagar, Pune-411005, India. (Facilities : Luxury rooms, hot and cold water with showers, channel music, television, round the clock service, pure vegetarian breakfast) Rates : about Rs.400/- or US$12 per person per day(with double occupancy) 2. Hotel Pride Executive ; 5, University Road, Shivajinagar, Pune-411005, India. (Facilities : Excellent quality luxury rooms, hot and cold water with showers, channel music, television, round the clock service, breakfast fruit basket, swimming pool) Rates : about Rs.2000/- or US$60 per person per day (with double occupancy). 3. Hotel Sahara ; Senapati Bapat Road, Pune-411 007, India. (Facilities : Luxury rooms, hot and cold water with showers, free shoe polishing, laundry service, channel music, television, round the clock service, pure vegetarian breakfast). Rates : about Rs.350/- or US$11 per person per day (on double occupancy basis). 4. Hotel Ranjit, 870/7 Bhandarkar Institute Road, Deccan Gymkhana, Pune-411 004. (Facilities : Round the clock service, laundry service, cold and hot water, doctor on call, breakfast, car rental, two-channel music) Rates : Rs.400/- or US$12 per person per day (with double occupancy). Sponsors for the Conference : University of Pune Council of Scientific & Industrial Research (CSIR), New Delhi Co-sponsors : National Chemical Laboratory (NCL), Pune Centre for Development of Advanced Computing(C-DAC), Pune HOPE TO SEE YOU IN PUNE IN JANUARY 1998 ! ... From mbigi@dial-up.unipi.it Thu May 22 09:55:28 1997 Received: from mixer.unipi.it for mbigi@dial-up.unipi.it by www.ccl.net (8.8.3/950822.1) id JAA12376; Thu, 22 May 1997 09:02:44 -0400 (EDT) Organization: Centro SERRA University of Pisa - Italy Received: from petra.farm.unipi.it (slip08.unipi.it [131.114.21.29]) by mixer.unipi.it (8.8.5/8.8.5) with SMTP id PAA18919 for ; Thu, 22 May 1997 15:03:50 -0100 (GMT) Resent-Message-Id: <199705221603.PAA18919@mixer.unipi.it> Comments: Authenticated sender is Resent-from: "Michele Bigi" Resent-to: chemistry@www.ccl.net Resent-date: Thu, 22 May 1997 14:42:57 +0000 Received: from petra.farm.unipi.it (slip02.unipi.it [131.114.21.23]) by mixer.unipi.it (8.8.5/8.8.5) with SMTP id PAA19074; Thu, 8 May 1997 15:05:19 -0100 (GMT) Message-Id: <199705081605.PAA19074@mixer.unipi.it> Comments: Authenticated sender is From: "Michele Bigi" To: Redime HADJI Date: Thu, 8 May 1997 13:56:00 +0000 MIME-Version: 1.0 Content-transfer-encoding: 7BIT Subject: chemistry@www.ccl.net Reply-to: mbigi@farm.unipi.it CC: mbigi@farm.unipi.it X-Confirm-Reading-To: mbigi@farm.unipi.it X-pmrqc: 1 Return-receipt-to: mbigi@farm.unipi.it Priority: normal X-mailer: Pegasus Mail for Win32 (v2.42a) Content-Type: text/plain; charset=US-ASCII On Tue, 6 May 1997, Redime HADJI wrote: > > > Hi, > > I am looking for any information (references, reviews, methodology, > etc.) about molecular dynamics simulations of MICELLE(S), > conformational behaviour of peptides in micelles (in paticular in > SDS micelles). > > Any hints would be grately appreciated. I will summarize your > answers. > > Thank you very much in advance. > > Redime HADJI-PFEFFER A search oc Chemical Abstract (1996 and 1997 years) gave those results 124:212676 Molecular Dynamics Simulations of a Calcium Carbonate/Calcium Sulfonate Reverse Micelle. Tobias, Douglas J.; Klein, Michael L. J .Phys. Chem., 100(16), 6637-48 1996 125:124424 Molecular Dynamics Simulation of a Micellar System: 2,3,6,7,10,11-Hexakis(1,4,7-trioxaoctyl)triphenylene in Water. Bast, Tim; Hentschke, Reinhard Phys. Chem., 100(30),12162-12171 1996. 125:197082 Aggregation processes in self-associating polymer systems. Computer simulation study of micelles in the superstrong segregation regime. Khalatur, Pavel G.; Khokhlov, Alexei R.; Nyrkova, Irina A.; Semenov, Alexander N. Macromol. Theory Simul., 5(4), 713-747 1996. 124:235566 Wormlike micelles under shear flow: a microscopic model studied by nonequilibrium-molecular-dynamics computer simulations. Kroeger, M.; Makhloufi, R. Phys. Rev. E: Stat. Phys., Plasmas, Fluids, Relat. Interdiscip. Top., 53(3), 2531-6 1996. 125:152029 Investigation of molecular dynamics in water-surfactant-solid sorbent systems by low energy neutron scattering. Karmazina, T. V.; Slisenko, V. I.; Mironyuk, A. G. Fiz.-Khim. Metody Issled. Strukt. Din. Mol. Sist., Mater. Vseross. Soveshch., Volume 3, 128-131. Edited by: Gordeev, M. E. Mariiskii Politekhnicheskii Institut im. A. M. Gor'kogo: Ioshkar-Ola, Russia. (Russian) 1994. 125:188794 Dynamics of spin-labeled a-chymotrypsin in reverse micelles of differently charged surfactants. Caldarau, Horia; Timmins, Graham S.; Davies, Michael J.; Gilbert, Bruce C. J. Chem. Soc., Faraday Trans., 92(17), 3151-3155 1996. 124:169103 Reorientational properties of fluorescent analogs of the protein kinase C cofactors diacylglycerol and phorbol ester. Pap, Eward H. W.; Ketelaars, Martijn; Borst, Jan Willem; van Hoek, Arie; Visser, Antonie J. W. G. Biophys. Chem., 58(3), 255-66 1996. 125:186047 An NMR, CD, molecular dynamics and fluorometric study of the conformation of bradykinin antagonists B 9340, B 9430, B 9436 and B 9452 in water and in aqueous micellar solutions. Sejbal, Jan; Cann, John R.; Stewart, John M.; Gera, Lajos; Kotovych, George Immunopharmacology, 33, 198-200 1996. 125:248951 Some ESR spin probe and spin label studies of polymer systems. Wasserman, A. M.; Khazanovich, T. N.; Kasaikin, V. A. Appl. Magn. Reson., 10(1-3), 413-429 1996. 125:97105 Dynamical and structural properties of water/alcohol mixtures. Onori, G.; Santucci, A. Mol. Liq., 69, 161-181 1996. 124:261680 An NMR, CD, Molecular Dynamics, and Fluorometric Study of the Conformation of the Bradykinin Antagonist B-9340 in Water and in Aqueous Micellar Solutions. Sejbal, Jan; Cann, John R.; Stewart, John M.; Gera, Lajos; Kotovych, George Med. Chem., 39(6), 1281-92 1996. 124:196780 Lipid Chain Dynamics and Molecular Location of Diacylglycerol in Hydrated Binary Mixtures with Phosphatidylcholine: Spin Label ESR Studies. Schorn, Karl; Marsh, Derek Biochemistry, 35(12), 3831-6 1996. 124:168759 Taming the Ewald sum in molecular dynamics simulations of solvated proteins via a multiple time step algorithm. Procacci, Piero; Marchi, Massimo J. Chem. Phys., 104(8), 3003-12 1996. 124:80348 Restrained molecular dynamic study of the interaction between bovine k-casein peptide 98-111 and bovine chymosin and porcine pepsin. Plowman, Jeffrey E.; Creamer, Lawrence K. J. Dairy Res., 62(3), 451-67 1995. I hope that it will help, Thanks Michele U. Bigi Michele U. Bigi E-Mail: mbigi@farm.unipi.it From stephen_andruski@fmc.com Wed May 28 11:45:24 1997 Received: from igw.fmc.com for stephen_andruski@fmc.com by www.ccl.net (8.8.3/950822.1) id KAA19468; Wed, 28 May 1997 10:57:09 -0400 (EDT) Received: by igw.fmc.com id AA12737 (InterLock SMTP Gateway 3.0 for chemistry@www.ccl.net); Wed, 28 May 1997 09:56:26 -0500 Message-Id: <199705281456.AA12737@igw.fmc.com> Received: by igw.fmc.com (Internal Mail Agent-1); Wed, 28 May 1997 09:56:26 -0500 Mime-Version: 1.0 Date: Wed, 28 May 1997 10:42:10 -0500 From: stephen_andruski@fmc.com (STEPHEN ANDRUSKI) Subject: Re:Unrelated Questions To: toukie@zui.unizh.ch, chemistry@www.ccl.net Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part >>Question 1: In order to obtain Mulliken partial atomic charges for >>some work in which we are engaged, I prepared a Z-matrix for the >>molecule p-tolylacetylene ("tolac.mop"), as follows: >>am1 nointer >>p-tolylacetylene The problem is with the specific way the atoms are defined in the Z-matrix. This is a common problem with linear molecules in MOPAC. You can try defining the Z-matrix in a different way and this sometimes solves this kind of problem, but in this case that may not be possible. Using the keyword "nointer" only keeps the internal coordinates form printing. Using the keyword "xyz" will run the calculation in cartesian coordinates and should allow it to run properly. >>Question 2: I would like to know if there is some established >>quantitative measure of the "degree" of chirality. While a measure of the similarity between two enantiomers might have some utility (though I'm not sure what), the idea that one compound is "more chiral" than another one makes no sense to me. If anything, the number of chiral centers would make more sense as a measure of the amount of chirality, but even then I still don't see the utility of the concept. Perhaps you could elaborate on how this concept would be used. Dr. Stephen W. Andruski FMC Corporation stephen_andruski@fmc.com From berriz@chasma.harvard.edu Wed May 28 12:45:23 1997 Received: from chasma.harvard.edu for berriz@chasma.harvard.edu by www.ccl.net (8.8.3/950822.1) id MAA20129; Wed, 28 May 1997 12:18:00 -0400 (EDT) Received: by chasma.harvard.edu (AIX 3.2/UCB 5.64/4.03) id AA18554; Wed, 28 May 1997 12:14:22 -0400 Date: Wed, 28 May 1997 12:14:22 -0400 From: berriz@chasma.harvard.edu (Gabriel Berriz) Message-Id: <9705281614.AA18554@chasma.harvard.edu> To: chemistry@www.ccl.net Subject: MD: "gorques" ?? Hi. In a paper I'm reading on computational dynamics of anisotropic particles, the authors refer to "gorques", in the sentence: "...it is usual to avoid the evaluation of the torques ... and work instead with the so-called gorques...". The authors, it appears, assume familiari- ty with these "gorques", so they define them only implicitly, and don't bother to derive the equations in which they appear. Can someone recommend a reference that discusses these "gorques" more extensively? Thank you, Gabriel Berriz berriz@chasma.harvard.edu From elewars@alchemy.chem.utoronto.ca Wed May 28 13:45:17 1997 Received: from alchemy.chem.utoronto.ca for elewars@alchemy.chem.utoronto.ca by www.ccl.net (8.8.3/950822.1) id NAA20556; Wed, 28 May 1997 13:30:39 -0400 (EDT) Received: (from elewars@localhost) by alchemy.chem.utoronto.ca (8.7.4/8.7.3) id NAA01109 for chemistry@www.ccl.net; Wed, 28 May 1997 13:30:39 -0400 (EDT) Date: Wed, 28 May 1997 13:30:39 -0400 (EDT) From: "E. Lewars" Message-Id: <199705281730.NAA01109@alchemy.chem.utoronto.ca> To: chemistry@www.ccl.net Subject: DEGREE OF CHIRALITY Hello, This is in reply to a recent question s to whether one can speak of "degree of chirality", or whether it is an all-or-nothing property. There is a review paper in Angewandte Chemie, roughly 2 years ago, on chirality. Specifically addressed is this matter. Mislow has shown that you _can_ speak meaningfullly of degree of chirality (Kurt Mislow). Intuitively, CHDTF is less chiral than CIBrClF. So it's not like being alive or dead; indeed, with advances in medicine, death is becoming a matter of degree. E. Lewars ===== From citra@syrres.com Wed May 28 13:48:29 1997 Received: from syrres.syrres.com for citra@syrres.com by www.ccl.net (8.8.3/950822.1) id NAA20420; Wed, 28 May 1997 13:08:04 -0400 (EDT) Date: Wed, 28 May 97 11:47 EST Message-ID: <9705281147.AA08524@syrres.syrres.com> Received: from syrres.com by syrres.syrres.com; Wed, 28 May 97 11:47 EST X-Sender: citra@srcinet.syrres.com X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: chemistry@www.ccl.net From: Mario Citra Subject: chirality S. Shapiro wrote: "Question 2: I would like to know if there is some established quantitative measure of the "degree" of chirality." One way to quantify this is with rotational strength and dichroism. Chiral molecules exhibit dichroism (circular), and this is quantified by the rotational strength which is a quantum mechanical property. The rotational strength is the imaginary part of the dot product of electric dipole transition moment and magnetic dipole transition moment. Regards, Mario J. Citra Syracuse Research Corporation Merrill Lane Syracuse, New York 13210-4080 phone 315-426-3462 fax 315-426-3429 email citra@syrres.com Regards, Mario J. Citra PhD Syracuse Research Corporation Merrill Lane Syracuse, New York 13210-4080 phone 315-426-3462 fax 315-426-3429 email citra@syrres.com From RHERRMAN@nucleus.org.chemie.tu-muenchen.de Wed May 28 15:45:19 1997 Received: from sunsrv5.lrz-muenchen.de for RHERRMAN@nucleus.org.chemie.tu-muenchen.de by www.ccl.net (8.8.3/950822.1) id PAA21461; Wed, 28 May 1997 15:24:46 -0400 (EDT) Received: from nucleus.org.chemie.tu-muenchen.de by sunsrv5.lrz-muenchen.de; Wed, 28 May 97 21:24:45 +0200 Received: from NUCLEUS/TEMPQ by nucleus.org.chemie.tu-muenchen.de (Mercury 1.1); Wed, 28 May 97 21:24:43 GMT From: "Dr. Rudolf Herrmann" To: "Hr. Dr. S. Shapiro" Date: Wed, 28 May 1997 21:24:13 GMT Subject: Re: CCL: Chirality CC: CHEMISTRY@www.ccl.net Return-receipt-to: "Dr. Rudolf Herrmann" Priority: normal X-mailer: Pegasus Mail v3.40 Message-Id: <338c867d31cc002@sunsrv5.lrz-muenchen.de> On 22 May 97 at 10:03, Hr. Dr. S. Shapiro wrote: > > Question 2: I would like to know if there is some established quantitative > measure of the "degree" of chirality. For example, consider the chiral > molecules CR1R2R3R4, where in one case R1 = H, R2 = D, R3 = T, and R4 = F, > whereas in another case R1 = H, R2 = naphthyl, R3 = n-octyl, and R4 = NO2. > Whilst both molecules are chiral, it is clear that the structural variation > when R1 = H, R2 = naphthyl, R3 = n-octyl, and R4 = NO2 makes this a "more" > chiral molecule than when R1 = H, R2 = D, R3 = T, and R4 = F. But how to > express in a quantitative fashion that the second chiral molecule is "more" > chiral than the first? I thought that perhaps the RMS deviation between the > two enantiomorphs of each of these chiral molecules might provide > quantification of chirality. Does anyone have any further, possibly better, > suggestions? > Dear Dr. Shapiro, there has already a lot of work been done on the problem of how to quantify chirality. Most approaches have some merits, but none is completely satisfying. I will just quote a few references and leave the judgement to you: Very good review article on the problem "what is the most chiral tetrahedron"; see also the literature quoted therein: A.B.Buda, T.Auf der Heyde, K.Mislow, Angew.Chem 104 (1992) 1012. Chirality functions: E.Ruch, I.Ugi, Top.Stereochem. 4 (1969) 99; Angew.Chem. 89 (1977) 67. Chiral genus: J.Dugundji, R.Kopp, D.Marquarding, I.Ugi, Top.Curr.Chem. 75 (1976) 165. On the problem how to reconcile theory (or should I say philosophy) with experiment: K.Mislow, P.Bickart, Isr.J.Chem. 15 (1976/77) 1. You may also have a look to quantum-chemical treatment of chirality: M.Quack, Angew.Chem. 101 (1989) 588. Hope this will help you. Yours sincerely, R.Herrmann. Dr. Rudolf Herrmann Institut fuer Organische Chemie und Biochemie der Technischen Universitaet Muenchen Lichtenbergstr. 4 D-85747 Garching Tel. + 49 - 89 - 28913325 Fax + 49 - 89 - 28912727 From klangevin@ibcusa.com Wed May 28 16:45:19 1997 Received: from elektra.ultra.net for klangevin@ibcusa.com by www.ccl.net (8.8.3/950822.1) id PAA21618; Wed, 28 May 1997 15:59:57 -0400 (EDT) Received: from cleopatra.ultra.net (cleopatra.ultra.net [199.232.56.35]) by elektra.ultra.net (8.8.5/ult1.06) with ESMTP id PAA27399 for ; Wed, 28 May 1997 15:59:46 -0400 (EDT) Received: from ultra-gw.ibcusa.com (ultra-gw.ibcusa.com [204.249.176.245]) by cleopatra.ultra.net (8.8.5/ult1.05) with SMTP id PAA19702 for ; Wed, 28 May 1997 15:59:31 -0400 (EDT) Received: from ccMail by ultra-gw.ibcusa.com (SMTPLINK V2.11 PreRelease 4) id AA864860230; Wed, 28 May 97 15:57:11 EST Date: Wed, 28 May 97 15:57:11 EST From: "Kristen Langevin" Message-Id: <9704288648.AA864860230@ultra-gw.ibcusa.com> To: chemistry@www.ccl.net Subject: Data Management Hello, I wanted to inform you of a symposium IBC USA Conferences is sponsoring entitled, "Data Management for Drug Discovery and Design", June 23-24, 1997 in San Francisco, CA. You may view our brochure and register on-line at: http://www.ibcusa.com/conf/datamanagement. If you'd prefer, you may request additional information by contacting me at klangevin@ibcusa.com. Sincerely, Kristen P. Langevin Marketing Manager From jesus@canarylab.chem.nyu.edu Wed May 28 16:47:39 1997 Received: from canarylab.chem.nyu.edu for jesus@canarylab.chem.nyu.edu by www.ccl.net (8.8.3/950822.1) id QAA21704; Wed, 28 May 1997 16:22:10 -0400 (EDT) Received: by canarylab.chem.nyu.edu (940406.SGI/931108.SGI.AUTO.ANONFTP) for CHEMISTRY@www.ccl.net id AA04155; Wed, 28 May 97 16:36:26 -0400 From: jesus@canarylab.chem.nyu.edu (Jesus M. Castagnetto M.) Message-Id: <9705282036.AA04155@canarylab.chem.nyu.edu> Subject: Re: CCL:DEGREE OF CHIRALITY To: CHEMISTRY@www.ccl.net Date: Wed, 28 May 1997 16:36:17 -0500 (EDT) Organization: New York University, Department of Chemistry X-Mailer: ELM [version 2.4 PL21] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit With respect to Mislow papers, there are two references: Angew. Chem., Int. Ed. Engl. 1992, 31(4), 989-1007 J. Math. Chem. 1995, 17(1), 35-53 Also with respect to the rotational strenght (R), a better quantification takes into accoun the ansitropic and the isotropic contributions, and this can be done by using Kuhn's g-number (Kuhn, W. Trans. Faraday Soc. 1930, 26, 293) which is relates to R and D, so direct comparison of dissimilar chromophores is possible. Good discussions on this last topic are in the book "Stereochemistry of Organic Compounds" by E. L. Eliel et. al. Hope this helps. ----- Jesus M. Castagnetto M. | "Organic Chemistry: The practice Dep.of Chemistry - New York University | of transmuting vile substances 4 Washington Pl, Room 514. NY 10003 | into publications" (The Last Word- jesus@canarylab.chem.nyu.edu | The Ultimate Scientific Dictionary) * URL: http://pages.nyu.edu/~jqc6280/ * LAB: http://pages.nyu.edu/~canary/ From mac@elara.tripos.com Wed May 28 16:49:23 1997 Received: from gatekeeper.tripos.com for mac@elara.tripos.com by www.ccl.net (8.8.3/950822.1) id QAA21731; Wed, 28 May 1997 16:27:20 -0400 (EDT) From: Received: (from news@localhost) by gatekeeper.tripos.com (8.6.12/8.6.12) id PAA00425 for <@gatekeeper.tripos.com:CHEMISTRY@www.ccl.net>; Wed, 28 May 1997 15:29:58 -0500 Received: from elara.tripos.com(192.160.145.60) by gatekeeper.tripos.com via smap (V1.3) id sma000423; Wed May 28 15:29:46 1997 Received: from callisto by elara via ESMTP (951211.SGI.8.6.12.PATCH1042/951211.SGI.AUTO) for id PAA10813; Wed, 28 May 1997 15:29:43 -0500 Received: by callisto (950413.SGI.8.6.12) id PAA16632; Wed, 28 May 1997 15:29:39 -0500 Date: Wed, 28 May 1997 15:29:39 -0500 Message-Id: <199705282029.PAA16632@callisto> To: CHEMISTRY@www.ccl.net Subject: reminder, World Tour on Web Technologies Reminder: Tripos, Inc. and Silicon Graphics, Inc. are hosting a worldwide series of seminars in June. 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From victor@ignet.odessa.ua Wed May 28 17:45:21 1997 Received: from ignet.ignet.odessa.ua for victor@ignet.odessa.ua by www.ccl.net (8.8.3/950822.1) id RAA22155; Wed, 28 May 1997 17:44:28 -0400 (EDT) Received: from 194.44.73.91.ignet.odessa.ua (L135.ignet.odessa.ua [195.138.67.135]) by ignet.ignet.odessa.ua (8.7.3/8.6.9) with SMTP id AAA08972; Thu, 29 May 1997 00:41:27 +0300 Message-ID: <338CA77B.4EDC@ignet.odessa.ua> Date: Thu, 29 May 1997 00:45:31 +0300 From: Victor Kuzmin Reply-To: victor@ignet.odessa.ua Organization: Home Office X-Mailer: Mozilla 3.0Gold (Win95; I) MIME-Version: 1.0 To: "Hr. Dr. S. Shapiro" CC: chemistry@www.ccl.net Subject: Re: CCL:Chirality References: <1.5.4.32.19970522080328.006652d0@highdent.zzmk.unizh.ch> Content-Type: text/plain; charset=koi8-r Content-Transfer-Encoding: 8bit Hr. Dr. S. Shapiro wrote: > > Dear Colleagues; > > I have two quite unrelated questions for which perhaps some CCLers > might be able to provide useful replies: > > > Question 2: I would like to know if there is some established quantitative > measure of the "degree" of chirality. For example, consider the chiral > molecules CR1R2R3R4, where in one case R1 = H, R2 = D, R3 = T, and R4 = F, > whereas in another case R1 = H, R2 = naphthyl, R3 = n-octyl, and R4 = NO2. > Whilst both molecules are chiral, it is clear that the structural variation > when R1 = H, R2 = naphthyl, R3 = n-octyl, and R4 = NO2 makes this a "more" > chiral molecule than when R1 = H, R2 = D, R3 = T, and R4 = F. But how to > express in a quantitative fashion that the second chiral molecule is "more" > chiral than the first? I thought that perhaps the RMS deviation between the > two enantiomorphs of each of these chiral molecules might provide > quantification of chirality. Does anyone have any further, possibly better, > suggestions? > > Thanks in advance to all responders. > > Sincerely, > > S. Shapiro > toukie@zui.unizh.ch Dear colleagues! More than ten years we research quantitative aspects of chirality. We elaborate the dissymmetry functions method , with which help it was possible to solve a number of applied tasks. Look for example: Kuz’min V.E. et al. J. Phys.Org.Chem., 1992, v.5, ¹ 6, p.295-298, 299-307, 308-316. We shall be glad to assist. Send coordinates interesting for you of structures, and we shall estimate a level chirality of them. Sincerely, Victor E. Kuz’min Head of Laboratory on Theoretical Chemistry A.V. Bogatsky Physico-Chemical Institute of NAN of Ukraine Lustdorfskaja doroga 86, Odessa 270080, Ukraine e-mail: victor@ignet.odessa.ua From ascanio@salve5.salve.edu Wed May 28 22:45:22 1997 Received: from salve5.salve.edu for ascanio@salve5.salve.edu by www.ccl.net (8.8.3/950822.1) id WAA23144; Wed, 28 May 1997 22:31:24 -0400 (EDT) Received: by salve5.salve.edu (AIX 3.2/UCB 5.64/4.03) id AA41194; Wed, 28 May 1997 22:28:01 -0400 Date: Wed, 28 May 1997 22:28:01 -0400 (EDT) From: Ascanio DiPippo To: CHEMISTRY@www.ccl.net Subject: "Degree of Chirality" Message-Id: Mime-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="-969821433-1027100827-864872881=:43844" This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. Send mail to mime@docserver.cac.washington.edu for more info. ---969821433-1027100827-864872881=:43844 Content-Type: TEXT/PLAIN; charset=US-ASCII Colleagues, Could someone, please, define, precisely, "degree of chirality" ? Thank you. Ascanio ---969821433-1027100827-864872881=:43844 Content-Type: TEXT/PLAIN; charset=US-ASCII; name=sumus Content-Transfer-Encoding: BASE64 Content-ID: Content-Description: U3VtdXMgdW5pdmVyc2l0YXMuICBTdW11cyB1bml2ZXJzaXRhcyA/ICBTdW11 cyB1bml2ZXJzaXRhcyAhGg== ---969821433-1027100827-864872881=:43844-- From jorge@cosm.sc.edu Wed May 28 23:45:24 1997 Received: from cosmos.psc.sc.edu for jorge@cosm.sc.edu by www.ccl.net (8.8.3/950822.1) id XAA23320; Wed, 28 May 1997 23:16:45 -0400 (EDT) Received: (from jorge@localhost) by cosmos.psc.sc.edu (8.6.12/8.6.12) id DAA12324; Thu, 29 May 1997 03:16:47 GMT Date: Thu, 29 May 1997 03:16:47 GMT From: Jorge Seminario Message-Id: <199705290316.DAA12324@cosmos.psc.sc.edu> To: CHEMISTRY@www.ccl.net Subject: rotational barrier: experiment and theory Cc: jorge@cosmos.psc.sc.edu Hello dear members: I wonder if you could help me to clear up some problems to interpret my colleagues' experiment by using our computational tools. The molecule consists in two benzene rings connected by two carbon atoms. The experiment on Ph-C-C-Ph (where the central C-C bond is triple and the adjacents are single) indicates that a sudden rotation of one of the benzene rings with respect to the other is initiated when the temperature reaches 30 K. The calculations yield a barrier of about 0.5 kcal/mol for the rotation of the benzene rings. The argument against this theoretical barrier is that at 30K, the kT (or RT) available for this mode is only 0.06 kcal/mol and therefore, the rotation of the phenyl groups is not possible because the barrier is almost ten times bigger than the available energy. So, the calculation might be wrong. Well, we repeated the calculation with several other methods and the results are practically the same. However, a gross estimate, indicates that the total thermal energy in this molecule at 30K is about .5 kcal/mol, this mean, counting all the other vibrational modes and other contributions to the thermal energy. Now, the main question to all of you is if this total thermal energy can be available for the rotation? if not, why this rotation could happen? On this lines, [Morrison and Boyd 5thEd. page80] indicates a "lack of understanding" for the rotational barrier of ethane, which is 3 kcal/mol (this would correspond to a T=1500) however at 300 K ethane seems to have practically free rotation. I am tempted to infer that whatever explains ethane to over-pass the barrier of 3 kcal/mol at 300K, will also explain the experiment above. Interestingly, the total thermal energy of ethane at 300 K is about 3kcal/mol. Sorry if this is too trivial for the net. Your comments, suggestions and ideas of any kind are highly appreciated. Cordially Jorge Seminario -------------------------------------------- Jorge M. Seminario Department of Chemistry and Biochemistry University of South Carolina Columbia, South Carolina 29208 Tel: 803-777-9567 Fax: 803-777-9521 email: jorge@cosm.sc.edu --------------------------------------------