THE CHARGE DENSITY OF 9-ETHYLADENINE-5,5-DI- ETHYLBARBITURIC ACID. M. Niederhut and B.M. Craven. Department of Crystallography, University of Pittsburgh, Pittsburgh, PA 15260

Barbital is a molecule that binds with many biological compounds. In binding with adenine, as shown by Voet, (1972, JACS, 94:23, 8213-8222.), it forms layers of hydrogen bonds of both Watson-Crick and Hoogsteen types.

New low temperature data of the adenine-barbital complex, space group P1, were collected using MoK[[alpha]] radiation ([[lambda]]=0.7093Å). Multipole refinements and charge density plots will be presented and discussed.

This work is supported by a grant, GM-39513 from NIH.