Sent to CCL by: "N. Sukumar"
[nagams_-_rpi.edu]
By adding 2pi (360deg) to it (as Hugo has already
explained).
N. Sukumar
Professor of Chemistry
Shiv Nadar
University,
India
----------------------------
"Pursue something so important that
even if you fail, the world is better
off with you having tried." -- Tim
O'Reilly
http://as.wiley.com/WileyCDA/WileyTitle/productCd-0470769009.html==============Original
message text===============
On Sun, 10 Nov 2013 5:08:07 EST "Hamid Shojaei
shojaei81^gmail.com" wrote:
Sent to CCL by: "Hamid Shojaei"
[shojaei81**gmail.com]
Dear Dr. Hugo Alejandro Jimnez
Vzquez,
Thank you very much for your comment on my question in CCL.
in
some of torsional angles we have differences in a negative sign. How
can I
ignore this sign.
Regards,
shojaei
> "Hugo
Alejandro Jimenez Vazquez hjimenez[*]woodward.encb.ipn.mx" wrote:
>
> Sent to CCL by: Hugo Alejandro Jimenez
Vazquez
[hjimenez^_^woodward.encb.ipn.mx]
> This message is in
MIME format. The first part should be readable text,
> while
the remaining parts are likely unreadable without MIME-aware tools.
>
> ---862666845-1686960974-1384055120=:5311
> Content-Type:
TEXT/PLAIN; CHARSET=ISO-8859-1; format=flowed
> Content-Transfer-Encoding:
QUOTED-PRINTABLE
> Content-ID:
<Pine.LNX.4.64.1311092147191.5385(a)woodward.encb.ipn.mx>
>
>
> To be sincere, I do not see those "big differences" you mention. If
you=20
> take into account that the negative angles can be converted to
positive by=
> =20
> adding 360, what you have is:
>
> 175.1 vs. 184.0
> 178.9 vs. 183.0
>
177.0 vs. 179.8
> 178.7 vs. 182.2
> 174.2 vs.
169.7
> 91.0 vs. 138.2
>
> At least for me, only
the
values for the last angle differ by a more than=
> =20
> reasonable
amount; out of all the others, the first one differs the most,=
>
=20
> by less than 10=B0.
>
> I have no idea about what your
molecule looks like. In addition, you do=20
> not mention how you got the
experimental values, but I would assume they=20
> came from an X-ray
diffraction structure. You should be aware that the=20
> gas phase
structure (from the calculations) does not necessarily have to=20
> be
exactly the same as the structure in the crystal. In the solid phase=20
>
the geometry is influenced by nonbonded interactions with all the=20
>
neighbouring molecues which might lead to a slight or severe changes
with=
> =20
> respect to the gas phase structure, particularly in
floppy molecules.
>
> The gas phase geometry obtained through
calculation also depends on the=20
> level of
theory employed, something that you do not mention either.
>
>
Regards,
>
> ---
> Hugo A. Jimenez Vazquez
>
hjimenez(a)woodward.encb.ipn.mx
> Departamento de Quimica Organica
>
ENCB-IPN
> Mexico
>
>
> On Sat, 9 Nov 2013, Hamid
Shojaei Shojaei81..gmail.com wrote:
>
> >
> > Sent to
CCL by: "Hamid Shojaei" [Shojaei81-#-gmail.com]
> > Dear
All,
> >
> > I do some structural calculations but I see big
differences between theor=
> etical
> > and experimental torsion
angles.
> >
> > Torsion angle=09
Experimental=09Theoretical
> > N(2)C(2)C(3)C(8)=09 175.1=09
-175.965
> > O(1)C(2)C(3)C(4)=09 178.94=09
-177.005
> > C(8)C(3)C(4)N(3)=09177.0
179.837
> >
C(2)C(3)C(4)C(5)=09 178.73=09 -177.808
> >
C(31)N(3)C(4)C(3)=09 174.2=09 169.686
> >
C(4)N(3)C(31)C(32)=09 91.0=09 138.193
>
>
> >
> > Any idea explaining such a differences is highly
appreciated.
> >
> >
> >
>
---862666845-1686960974-1384055120=:5311--
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