Crystal Structures of 1,1′-di(2-propanone)-2,2′-biimidazole Dihydrazone and 2,6-diacetylpyridine Dihydrazone
The nucleophilic addition reactions between 1,1′-di(2-propanone)-2,2′-biimidazole or 2,6-diacetylpyridine and hydrazine hydrate afford 1,1′-di(2-propanone)-2,2′-biimidazole dihydrazone (1) and 2,6-diacetylpyridine dihydrazone (2), respectively. Compound 1 crystallizes in the orthorhombic space group P212121, with a = 9.042(2), b = 9.731(3), c = 15.683(4)Å, V = 1379.9(6)Å3 and Z = 4. Compound 2 crystallizes in the orthorhombic space group Pnma, with a = 10.948(2), b = 19.742(6), c = 4.566(1)Å, V = 986.9(4)Å3 and Z = 8. A pseudo center of inversion is present at the midpoint of the C-C bond joining the imidazole rings of 1, whose substituents crystallize in a trans configuration. The imidazole rings are rotated 2.5(3)° about the C-C bond. In contrast to the essentially planar structure of 2, the hydrazone substituent groups of 1 are at angles of 89.9(1)° and 88.4(1)° with respect to the plane of the adjacent imidazole moiety.
P. M. Secondo et al., "Crystal Structures of 1,1′-di(2-propanone)-2,2′-biimidazole Dihydrazone and 2,6-diacetylpyridine Dihydrazone," Journal of Chemical Crystallography, Springer Verlag, Jan 1997.
The definitive version is available at http://dx.doi.org/10.1007/BF02576571
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