Synthon polymorphism and pseudopolymorphism in co-crystals.The 4,4'-bipyridine-4-hydroxybenzoic acid structural landscape

摘要

Co-crystals of 4,4'-bipyridine and 4-hydroxybenzoic acid (1 ∶ 2) show synthon polymorphism with the former being more stable. A 2 ∶ 1 co-crystal is pseudopolymorphic within the same structural landscape with the structural roles of the two bipyridine N-atoms being distinct, as evidenced by mimicry by 4-phenylpyridine.