Acta Crystallographica Section B

Structural Science

Volume 59, Part 6 (December 2003)

research papers

Acta Cryst. (2003). B59, 794-801 [ doi:10.1107/S0108768103024984 ]

Variable-temperature neutron diffraction studies of the short, strong NO hydrogen bonds in the 1:2 co-crystal of benzene-1,2,4,5-tetracarboxylic acid and 4,4'-bipyridyl

J. A. Cowan, J. A. K. Howard, G. J. McIntyre, S. M.-F. Lo and I. D. Williams

Abstract: The 1:2 adduct of benzene-1,2,4,5-tetracarboxylic acid and 4,4'-bipyridyl at 100 K has been studied by single-crystal neutron diffraction at 20, 200 and 296 K. The structure contains two short, strong NO hydrogen bonds: one O-HN hydrogen bond [ON 2.6104 (17) Å at 20 K] and one short N-HO hydrogen bond [NO 2.5220 (17) Å at 20 K]. The N-H distance in the N-HO hydrogen bond changes from 1.207 (3) Å at 20 K to 1.302 (4) Å at 296 K and the NO distance increases to 2.5315 (16) Å at 296 K. At 200 K the H atom lies in an intermediate position 1.251 (6) Å from the N atom with an NO separation of 2.520 (4) Å. The O-HN hydrogen bond, on the other hand, does not change with temperature.

Keywords: variable-temperature neutron diffraction; hydrogen bonds.


	Structure factor file (CIF format) (115.5 kbytes) Contains datablock hex20

	Structure factor file (CIF format) (132.7 kbytes) Contains datablock hex296

	Structure factor file (CIF format) (121.4 kbytes) Contains datablock hexladi

	Structure factor file (CIF format) (157.5 kbytes) Contains datablock hex30x

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