Homoconjugated 4-aminopyridine salts: influence of anions on network topology

Abstract

The homoconjugated 4-aminopyridinium cation, (4-AP)₂H, has been examined as a tecton for hydrogen bonded networks. The reaction of 4-aminopyridinium with ½ equivalent of NH₄X (X = Cl, Br, BF₄ or PF₆) produced [(4-AP)₂H]X salts, which were characterized by single crystal X-ray crystallography. All four compounds crystallized with 4-connected, uninodal hydrogen bond network topologies. The BF₄ and PF₆ salts formed interpenetrated SrAl₂ and diamond networks, respectively. Both halide salts displayed an unprecedented non-interpenetrated, self-catenated network topology.