"Routine determination of molecular crystal structures from
powder diffraction data"
William I. F. David, Kenneth Shankland and Norman Shankland
Chemical Communications, 1998, Vol. 8,931-932
This demonstrates the structure solutions of three previously
unknown crystal structures by the application of simulated annealing
using extracted intensities. Of note is
- the size and internal flexibility of the structures (up to 10
internal torsions)
- multiple fragment movement
- the speed with which the solutions were obtained
- the accuracy of the answers, given the limited data range used
The picture of the powder solution of capsaicin versus the single
crystal structure of capsaicin should interest those who feel it
is not possible to refine close to an answer using extracted
intensities. And just in case you're saying "ah, so they knew
the single crystal structure", no we didn't. We just measured
it later to head off the cynics who would not believe that the
powder structure was correct......
Cheers,
Kenneth
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Dr. Kenneth Shankland,ISIS Facility,Rutherford Appleton Laboratory
Chilton,Didcot,Oxon OX11 0QX,United Kingdom
Tel : +44 1235 44 6381
Fax : +44 1235 44 5720
E-Mail: k.shankland@rl.ac.uk
Date: 21-Apr-98
Time: 19:23:40
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-- Dr. Kenneth Shankland,Building R3,ISIS Facility,Rutherford Appleton LaboratoryChilton,Didcot,Oxon OX11 0QX,United KingdomTel : +44 1235 44 6381 Fax : +44 1235 44 5720Email : k.shankland@rl.ac.uk