From owner-chemistry@ccl.net Tue Apr 5 09:26:00 2011 From: "Eduardo edulsa- -ufpr.br" To: CCL Subject: CCL:G: About optical rotation calculation Message-Id: <-44292-110405072400-32307-sKFt/Hgs6iQYNm6ZnvScbw,+,server.ccl.net> X-Original-From: Eduardo Content-Type: multipart/alternative; boundary="------------080206040006060909040809" Date: Tue, 05 Apr 2011 08:23:39 -0300 MIME-Version: 1.0 Sent to CCL by: Eduardo [edulsa[A]ufpr.br] This is a multi-part message in MIME format. --------------080206040006060909040809 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Dear CCLers First it all, thanks to Dr. Borsosy and to Richard J. Wood for their replies. Unfortunately, I do not have access to Turbomole suite. In my case, the molecule that I am interested carries 4 optical active centres (2 of them are fixed), so Dr. Borosy confirmed what I suspected: algoritms were implemented aiming simple enantiomeric molecules (only one optical active center). Please, I would like to know if is there some program, free to academics, which should be able to calculate optical rotation for not too small (40 heavy atoms) molecules. Thank you in advance Yours Eduardo 07:00, Andras Borosy andras.borosy_+_givaudan.com wrote: > > Dear Eduardo, > > My experience is that Gaussian is not a very reliable application in > general. I do not know what its OR module is like in particular but I > would try the same computation by using Turbomole. It has a decent OR > calculation algorithm: Chemical Physics Letters 361 (2002) 321–328. > > If the molecule has too many rotatable bonds, these OR calculation > algorithms do not work: Current Organic Chemistry, 2010, 14, 1612-1628. > > Best wishes, > > > Dr. András Péter Borosy > Scientific Modelling Expert > > Fragrance Research > Givaudan Schweiz AG - Ueberlandstrasse 138 - CH-8600 - Dübendorf > - Switzerland > T:+41-44-824 2164 - F:+41-44-8242926 - http://www.givaudan.com > > > > > > *"Eduardo edulsa^_^ufpr.br" * > Sent by: owner-chemistry+andras.borosy==givaudan.com[a]ccl.net > > 28.03.2011 20:18 > Please respond to > "CCL Subscribers" > > > > To > "Borosy, Andras " > cc > > Subject > CCL:G: About optical rotation calculation > > > > > > > > > > > Sent to CCL by: Eduardo [edulsa|a|ufpr.br] > Dear CCLers > > I am performing some calculations (g03) aiming the optical rotation > properties. My first test was a s-valinol molecule (CAS 2026-48-4). > After a geometry optimization step (opt=tight), I got a value for > Alpha-D equals to -158.98 deg. The experimental value is + 16.9 deg. I > am get confuse because, unless I was strongly wrong, they are not the > same despite -160 and +20 be complementary angles. So please, could > anyone help me to explain and understand what is happening? > > My best wishes > > Eduardo > > -- > Eduardo Lemos de Sa > Associated Professor at Chemistry Department > Universidade Federal do Parana > Dep. Quimica, P. Box 19081, 81531-990 Curitiba PR / Brazil > phone: +55(41)33613300 > fax : +55(41)33613186> > > -- Eduardo Lemos de Sa Associated Professor at Chemistry Department Universidade Federal do Parana Dep. Quimica, P. Box 19081, 81531-990 Curitiba PR / Brazil phone: +55(41)33613300 fax : +55(41)33613186 --------------080206040006060909040809 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit Dear CCLers

First it all, thanks to Dr. Borsosy and to Richard J. Wood for their replies.

Unfortunately, I do not have access to Turbomole suite. In my case, the molecule that I am interested carries 4 optical active centres (2 of them are fixed), so Dr. Borosy confirmed what I suspected: algoritms were implemented aiming simple enantiomeric molecules (only one optical active center).

Please, I would like to know if is there some program, free to academics, which should be able to calculate optical rotation for not too small (40 heavy atoms) molecules.

Thank you in advance

Yours

Eduardo

07:00, Andras Borosy andras.borosy_+_givaudan.com wrote:

Dear Eduardo,

My experience is that Gaussian is not a very reliable application in general. I do not know what its OR module is like in particular but I would try the same computation by using Turbomole. It has a decent OR calculation algorithm: Chemical Physics Letters 361 (2002) 321–328.

If the molecule has too many rotatable bonds, these OR calculation algorithms do not work: Current Organic Chemistry, 2010, 14, 1612-1628.

Best wishes,

Dr. András Péter Borosy
Scientific Modelling Expert

Fragrance Research
Givaudan Schweiz AG - Ueberlandstrasse 138 - CH-8600 - Dübendorf - Switzerland
T:+41-44-824 2164 - F:+41-44-8242926 - http://www.givaudan.com

"Eduardo edulsa^_^ufpr.br" <owner-chemistry[a]ccl.net>
Sent by: owner-chemistry+andras.borosy==givaudan.com[a]ccl.net
28.03.2011 20:18

Please respond to
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Subject
CCL:G: About optical rotation calculation

Sent to CCL by: Eduardo [edulsa|a|ufpr.br] Dear CCLers I am performing some calculations (g03) aiming the optical rotation properties. My first test was a s-valinol molecule (CAS 2026-48-4). After a geometry optimization step (opt=tight), I got a value for Alpha-D equals to -158.98 deg. The experimental value is + 16.9 deg. I am get confuse because, unless I was strongly wrong, they are not the same despite -160 and +20 be complementary angles. So please, could anyone help me to explain and understand what is happening? My best wishes Eduardo -- Eduardo Lemos de Sa Associated Professor at Chemistry Department Universidade Federal do Parana Dep. Quimica, P. Box 19081, 81531-990 Curitiba PR / Brazil phone: +55(41)33613300 fax : +55(41)33613186 E-mail to subscribers: CHEMISTRY[a]ccl.net or use: http://www.ccl.net/cgi-bin/ccl/send_ccl_message E-mail to administrators: CHEMISTRY-REQUEST[a]ccl.net or use http://www.ccl.net/cgi-bin/ccl/send_ccl_message http://www.ccl.net/chemistry/sub_unsub.shtml Before posting, check wait time at: http://www.ccl.net Job: http://www.ccl.net/jobs Conferences: http://server.ccl.net/chemistry/announcements/conferences/ Search Messages: http://www.ccl.net/chemistry/searchccl/index.shtml http://www.ccl.net/spammers.txt RTFI: http://www.ccl.net/chemistry/aboutccl/instructions/

-- 
Eduardo Lemos de Sa
Associated Professor at Chemistry Department
Universidade Federal do Parana
Dep. Quimica, P. Box 19081, 81531-990 Curitiba PR / Brazil
phone: +55(41)33613300
fax  : +55(41)33613186

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