1 / 8

Kamil Dziubek & Andrzej Katrusiak

DIFFERENCES IN MOLECULAR ENVIRONMENTS OF POLYMORPHS. Kamil Dziubek & Andrzej Katrusiak. In dealing with a polymorphic s ystem perhaps the fundamental question is how similar or how different are the various crystal structures.(Joel Bernstein 2002).

gefen
Télécharger la présentation

Kamil Dziubek & Andrzej Katrusiak

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. DIFFERENCES IN MOLECULAR ENVIRONMENTS OF POLYMORPHS Kamil Dziubek & Andrzej Katrusiak In dealing with a polymorphic systemperhaps the fundamental question is how similar or how different are the various crystal structures.(Joel Bernstein 2002)

  2. What can be different in crystal structures?How can these differences be measured? Chemical composition Patterns of H-bonding (graph-set analysis) Intermolecular interactions Hirshfeld surfaces Intermolecular distances (distancestruct-1vs. distancestruct-2 plot) Z. Kristallogr. 219 (2004) 1-11

  3. Phase transitions in 1,3-cyclohexanedione Etter et al., J.Am.Chem.Soc.,108 (1986) 5871-5876. Katrusiak, J. Mol. Struct., 269 (1992) 329-354.

  4. Polymorphism of maleic hydrazide Cradwick, Nature, 258 (1975) 774. Katrusiak, Acta Cryst. C49, (1993) 36-39.

  5. Polymorphism of resorcinol Robertson, Proc. Royal Soc. London , 157 (1936) 79-99. Robertson; Ubbelohde, Proc. Royal Soc. London , 167 (1938) 122-135.

  6. ‘Pseudopolymorphs’ ? Acta Cryst B51 (1995) 999-1003

  7. Advantages of the d-d plots • Totally user-immune (independent of the unit-cell or symmetry assignment, or atoms labelling and choise of molecules) • Provides quantitative measures how similar or how diferent structures are, in [Å]’s • Very simple – pen and paper required... or can be facilitated by programs. Disadvantages NONE(?)

  8. Applications of d-d plots • Comparing polymorphs • Analysis of structures with several symmetry-independent molecules • Measuring differences between isostructural crystals • Comparing the same phase at different thermodynamical conditions • Data validation

More Related