Chemical Diversity in Hydrogen-Bond Patterns. Raymond E. Davis, Department of Chemistry and Biochemistry. The University of Texas at Austin, Austin, TX 78712-1167, USA and Joel Bernstein, Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel.

Studies of crystal structure data in the CSD often reveal a wide chemical diversity for a particular hydrogen-bond pattern (HBP). This suggests a hydrogen-bond pattern "functionality" that can cut across the traditional boundaries of chemical functionality, and that this HBP functionality can be a important guide in the design of substances with a desired, predetermined structure.

Our current work on hydrogen-bond patterns is focused in these areas:

Diversity of chemical functionalities. Which chemical functional groups are observed to display a particular hydrogen-bond pattern?

Frequency of occurrence of chemical functionalities. For a given chemical functional group, how common or how unusual is a particular hydrogen-bond pattern? Can structural features be identified -- in terms of chemical groupings, metrical aspects, or accompanying HBPs -- that correlate with the frequency of occurrence of a particular HBP for a given chemical functional group?

Variability of metrical aspects. Over what range of geometric constraints does a particular HBP vary?

Pattern cofunctionality. Do certain patterns often occur together? Could such pairs of patterns be considered to be cofunctional?

This presentation will discuss our recent work in these areas, including an introduction to the graph-set methodology for describing hydrogen-bond patterns.

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Supported in part by the Robert A. Welch Foundation, Grant F-233