Acta Crystallographica Section B

Structural Science

Volume 53, Part 1 (February 1997)

research papers

Acta Cryst. (1997). B53, 181-187 [ doi:10.1107/S0108768196011172 ]

Experimental and Theoretical Studies of Charge Density Distribution in E-Tetraethyl-1,4-diammoniumbut-2-ene.2PF₆

K. L. McCormack, P. R. Mallinson, B. C. Webster, D. S. Yufit, L. A. Slater and D. J. Robins

Abstract: The [PF₆]^- salt of E-tetraethyl-l,4-diaminobut-2-ene has been synthesized and the crystal structure determined. The experimental electronic charge distribution has been obtained by fitting a multipole model to low-temperature, high-resolution, single-crystal X-ray diffraction data. A high-level ab initio molecular orbital calculation has also been performed for the cation, which is used as an antifungal agent. Both experimental and theoretical Laplacian distributions display maxima only at the bond critical points. This correlates with a calculated electrostatic potential which is positive at all points.