Halobismuth(III) salts with substituted aminopyridinium cations

The crystal structures of six halobismuth(III) salts of variously substituted aminopyridinium cations display discrete mononuclear [BiCl 6 ] 3− and dinuclear [Bi 2 X 10 ] 4− anions ( X = Cl or Br), and polymeric cis -double-halo-bridged [Bi n X 4 n ] n − anionic chains ( X = Br or I). Bis(2-amino-3-ammoniopyridinium) hexachloridobismuth(III) chloride monohydrate, (C 5 H 9 N 3 ) 2 [BiCl 6 ]Cl·H 2 O, (1), contains discrete mononuclear [BiCl 6 ] 3− and chloride anions. Tetrakis(2-amino-3-methylpyridinium) di-μ-chlorido-bis[tetrachloridobismuth(III)], (C 6 H 9 N 2 ) 4 [Bi 2 Cl 10 ], (2), tetrakis(2-amino-3-methylpyridinium) di-μ-bromido-bis[tetrabromidobismuth(III)], (C 6 H 9 N 2 ) 4 [Bi 2 Br 10 ], (3), and bis(4-amino-3-ammoniopyridinium) di-μ-chlorido-bis[tetrachloridobismuth(III)] dihydrate, (C 5 H 9 N 3 ) 2 [Bi 2 Cl 10 ]·2H 2 O, (4), incorporate discrete [Bi 2 X 10 ] 4− anions ( X = Cl or Br), while catena -poly[2,6-diaminopyridinium [[ cis -diiodidobismuth(III)]-di-μ-iodido]], {(C 5 H 8 N 3 )[BiI 4 ]} n , (5), and catena -poly[2,6-diaminopyridinium [[ cis -dibromidobismuth(III)]-di-μ-bromido]], {(C 5 H 7 N 2 )[BiBr 4 ]} n , (6), include [Bi n X 4 n ] n − anionic chains ( X = Br or I). Structures (2) and (3) are isostructural, while that of (5) is a pseudomerohedral twin. There is no discernible correlation between the type of anionic species obtained and the cation or halide ligand used. The Bi III centres always have a slightly distorted octahedral geometry and there is a correlation between the Bi— X bond lengths and the number of classic N—H... X hydrogen bonds that the X ligand accepts, with a greater number of interactions corresponding with slightly longer Bi— X distances. The supramolecular networks formed by classic N—H... X hydrogen bonds include ladders, bilayers and three-dimensional frameworks.