Acta Crystallographica Section B

Structural Science

Volume 55, Part 1 (February 1999)

Acta Cryst. (1999). B55, 78-84 [doi:10.1107/S0108768198007848]

Experimental charge density and electrostatic potential in nicotinamide

Y. Miwa, T. Mizuno, K. Tsuchida, T. Taga and Y. Iwata

Abstract: The accurate crystal structure of nicotinamide, 3-pyridinecarboxamide, was determined from X-ray and neutron diffraction experiments: C₆H₆N₂O, M_r = 122.13, monoclinic, P2₁/c, Z = 4. The electron distribution at 150 K was determined by the maximum entropy method and the electrostatic potential in the crystal was calculated by Fourier convolution of the electron distribution. The electrostatic properties of the nicotinamide molecule depend on the molecular conformation. The asymmetric electrostatic potential field observed above and below the pyridine-ring plane is related to the rotation of the carboxamide group with respect to the pyridine plane. The positive potential peak at the C4 atom of the pyridine ring extends to the C=O-group side of the plane. The asymmetry of the potential on the C4 atom is consistent with the stereospecificity of hydride transfer in NAD⁺/NADH oxidoreduction.

Online 1 February 1999


	Structure factor file (CIF format) (275.1 kbytes) Contains datablock NAD295X

	Structure factor file (CIF format) (81.7 kbytes) Contains datablock NAD295N

	Structure factor file (CIF format) (381.0 kbytes) Contains datablock NAD150X

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