Dear Kristof,
Apart from things pointed out, a possibility to consider would also be the
presence of two different crystal types--of different compounds--in the same
reaction vessel.
Best regards,
Navdeep
---
On Wed, Aug 13, 2014 at 11:00:18AM +0200, Kristof Van Hecke wrote:
Dear,
I’m
Dear,
I’m struggling with the following (small molecule) problem:
We are trying to solve the structure of a metal-organic framework containing a
chiral compound.
The space group is most probably Pc, but when refining, SHELX gives the error
“Possible racemic twin or wrong absolute structure -
Hi, Pc may not be the space group for your crystal, if the molecule is
chiral. Seems like the data were forced to be reduced to a mirror_related
SG. Lijun
On Aug 13, 2014 2:00 AM, Kristof Van Hecke kristofrg.vanhe...@gmail.com
wrote:
Dear,
I’m struggling with the following (small molecule)
Twin laws are possible if there are 2 ways to index your cell, and
non-merefedral twinning is possible in any system depending on the cell.
I am not sure of the small molecule tools to check twinning though.
Eleanor Dodson
On 13 August 2014 05:58, Lijun Liu lijunli...@gmail.com wrote:
Hi, Pc
Hi folks
Pc *must* have both enantiomers, since it's got a glide plane ( =
mirror + translation parallel to mirror).
So the sample *cannot* be enantiopure if the space group is Pc (or P2/
c)...
BTW, Pc isn't a centrosymmetric space group.
Unless I'm wrong...
On 13 Aug 2014, at Wed13 Aug
Betreff: Re: [ccp4bb] Twinning in space group Pc
Hi, Pc may not be the space group for your crystal, if the molecule is chiral.
Seems like the data were forced to be reduced to a mirror_related SG. Lijun
On Aug 13, 2014 2:00 AM, Kristof Van Hecke
kristofrg.vanhe
Betreff: Re: [ccp4bb] Twinning in space group Pc
Hi, Pc may not be the space group for your crystal, if the molecule is
chiral. Seems like the data were forced to be reduced to a mirror_related
SG. Lijun
On Aug 13, 2014 2:00 AM, Kristof Van Hecke kristofrg.vanhe...@gmail.com
wrote
how many (quasi) equivalent positions do you think the chiral compound can
adopt in the organo-metal framework?
Or the organo-metal framework in the crystal?
If it's two, you can probably do alternate conformations - if there are more,
it could become impossible, even in P1.
Mark J van Raaij
Dear Kristof,
Have you tried to solve it with the new SHELXT? You can force it to
consider only chiral (Sohnke) space groups by putting -c on the command
line.
Best wishes, George
On 13.08.2014 11:00, Kristof Van Hecke wrote:
Dear,
I’m struggling with the following (small molecule)
