Chain, Sheet and Framework Structures in the Adducts of Phenylphosphonic Acid with 4,4'-Bipyridyl (1/1), Piperazine (2/1) and 1,4-Diazabicyclo[2.2.2]octane (2/1)

Phenylphosphonic acid–4,4′-bipyridyl (1/1), (1), C₆H₇O₃P.C₁₀H₈N₂, triclinic, P1¯, a = 6.9026 (8), b = 9.7086 (9), c = 12.201 (2) Å, α = 77.138 (9), β = 74.345 (10), γ = 75.477 (8)°, with Z = 2, is a salt, C₁₀H₉N₂ ⁺.[C₆H₅PO₂(OH)]⁻, containing singly protonated 4,4′-bipyridyl cations: the cations and anions are linked by N—H...O and C—H...O hydrogen bonds in an R^{2}_{2}(7) motif and these aggregates are linked into centrosymmetric R^{2}_{2}(8) dimers by O—H...O hydrogen bonds; the dimer units are linked into chains by C—H...O hydrogen bonds. Phenylphosphonic acid–piperazine (2/1), (C₆H₇O₃P)₂.C₄H₁₀N₂ (2), monoclinic, P2₁/n, a = 6.0042 (9), b = 19.746 (3), c = 8.651 (2) Å, β = 105.63 (2)°, with Z = 2, is a salt, C₄H₁₂N₂ ²⁺. [{C₆H₅PO₂(OH)}⁻]₂, containing doubly protonated piperazine: the anions are linked by O—H...O hydrogen bonds into centrosymmetric R^{2}_{2}(8) dimers and these dimers are linked to the centrosymmetric cations by N—H...O hydrogen bonds: each cation is hydrogen-bonded to four different anion dimers and each anion dimer is hydrogen-bonded to four different cations; the overall structure consists of two-dimensional sheets built from R^{4}_{6}(16) and R^{4}_{4}(18) rings. Phenylphosphonic acid–1,4-diazabicyclo[2.2.2]octane (2/1), (3), (C₆H₇O₃P)₂.C₆H₁₂N₂, monoclinic, P2₁/n, a = 6.3607 (3), b = 21.8300 (11), c = 14.5965 (9) Å, β = 92.558 (6)°, with Z = 4, is a salt in which one nitrogen of the diamine is fully protonated and the other is partially protonated: the anionic components are linked into C(4) chains by O—H...O hydrogen bonds, and these chains are cross-linked via the diamines by means of N—H...O and O—H...N hydrogen bonds. The resulting sheets built from R^{8}_{8}(34) rings are linked by C—H...O hydrogen bonds into a three-dimensional framework.