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) 321â328.
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. AndrÃs PÃter Borosy
Scientific Modelling Expert
Fragrance Research
Givaudan Schweiz AG Â- ÂUeberlandstrasse 138 Â- ÂCH-8600
Â- ÂDÃbendorf Â- ÂSwitzerland
T:+41-44-824 2164 Â- ÂF:+41-44-8242926 Â Â- Âhttp://www.givaudan.com
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 Â: +55(41)33613186
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--
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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