The robust {C(=O)OH···N(py)} heterosynthon persists in co-crystals formed between anthranilic acid and molecules with amide/pyridyl functionality

Abstract

Abstract Co-crystals formed between anthranilic acid and each of N,N′-bis(pyridin-2-ylmethyl)oxalamide (1) and N,N′-bis(pyridin-3-ylmethyl)oxalamide (2) have been formed from solutions containing 2:1 stoichiometric quantities of the reagents. In isomeric 1 and 2, the oxaläamide groups have both amide and pyridyl groups capable for forming hydrogen bonding interactions with the äcomponents of anthranilic acid. However, it is the {C(=O)OH···N(py)} heterosynthon that persists in both crystal structures pointing to the robustness of this synthon when both carboxylic acids and pyridyl groups are found in co-crystals. In 1, amine-H···O (oxalamide) and amide-H···N(amine) hydrogen bonds lead to layers that stack along the c-axis via C—H···O (carbonyl) interactions. In 2, the amine-H···O(oxalamide) hydrogen bonds lead to layers which are connected into a three-dimensional architecture by amide-N—H···O2 (carbonyl) interactions.