Crystal Structure Determination of Salts Obtained from Cocrystallization of 2,6-Dinitrobenzoic with 2,2′-Bipyridine and 4,4′-Bipyridine

The 2:1 cocrystallization of 2,6-dinitrobenzoic acid [LH] with 2,2'-bipyridine [2,2'-bpy] yields a salt cocrystal with formula [2,2'-bpyH][LH][L] which features a three component aggregate where the L(-) anion bridges [2,2'-bpyH]((+)) and neutral LH via N-H center dot center dot center dot O and O-H center dot center dot center dot O hydrogen bonds, respectively. The analogous experiment with 4,4'-bipyridine [4,4'-bpy] produced [4,4'-bpyH(2)][L](2), which also features a three component aggregate but with twofold symmetry and sustained by N-H center dot center dot center dot O hydrogen bonds. Compound 1 crystallizes in the monoclinic space group P2(1)/c with a = 7.707(4) , b = 20.966(10) , c = 15.267(7) , beta = 96.259 (10), and Z = 4. Compound 2 crystallizes in the monoclinic space group C2/c with a = 13.552(5) , b = 11.299(4) , c = 15.858 (6) , beta = 102.036(7) and Z = 4. The 2:1 cocrystallization of 2,6-dinitrobenzoic acid with each of 2,2'-bipyridine and 4,4'-bipyridine yields molecules of the same empirical formulae but very different crystal structures.