title: Conformational comparison of 1,2-dimethyl-6-oxo-1,6-dihydro-3,4'-bipyridine-5-carbonitrile free base and its hydrobromide monohydrate salt.
abstract: C13H11N3O (I), Mr = 225.25, monoclinic, P21/c, a = 11.713 (4), b = 7.891 (3), c = 12.154 (4) A, beta = 92.27 (4) degrees, V = 1123 (1) A3, Z = 4, Dx = 1.333 Mg m-3, lambda (Mo K alpha) = 0.71073 A, mu = 0.082 mm-1, F(000) = 472, T = 293 K, R = 0.063 for 2579 reflections. 5-cyano-1,2-dimethyl-6-oxo-1,6-dihydro-3,4'-bipyridinium bromide monohydrate, C13H12N3O+.Br-.H2O (II), Mr = 324.18, orthorhombic, Pbca, a = 7.2893 (8), b = 18.955 (3), c = 19.814 (3) A, V = 2738 (1) A3, Z = 8, Dx = 1.573 Mg m-3, lambda (Mo K alpha) = 0.71073 A, mu = 2.972 mm-1, F(000) = 1312, T = 293 K, R = 0.086 for 2292 reflections. The twist angle around the bipyridine C(1)-C(1)' bond is 66.6 (2) and 44.1 (8) degrees for the free base (I) and its salt (II), respectively. The larger C(3)'-N(4)'-C(5)' pyridine ring angle [121.8 (5) degrees] in the salt structure compared with the corresponding value for the free base [116.1 (1) degrees] suggests that N(4)' is a protonation site. The water molecule in the salt structure (II) is disordered with occupancy refined to 0.6 and 0.4.
authors.affiliation: Medical Foundation of Buffalo, Inc., NY 14203.
authors.forename: V
authors.initials: V
authors.lastname: Cody
authors.forename: K
authors.initials: K
authors.lastname: Suwínska
authors.forename: A
authors.initials: A
authors.lastname: Wojtczak
mesh_terms: D002316:Cardiotonic Agents / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D008968:Molecular Conformation; D015394:Molecular Structure; D011728:Pyridones / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D002316:Cardiotonic Agents; D011728:Pyridones; C069124:1,2-dimethyl-6-oxo-1,6-dihydro-3,4'-bipyridine-5-carbonitrile