[Me(HO) 2 P-(CH 2 ) 10 -P(O)OHMe] 2 [I 3 ] 2 · MeHO(O)P-(CH 2 ) 10 -P(O)OHMe (1) was synthesized and characterized by IR, Raman and NMR spectroscopy. Its structure was determined by singlecrystal X-ray diffraction (T = 100 K; space group P1). The structure consists of decane-1,10-diyl-bis-(methylphosphinic acid) molecules and the analogous mono-protonated cations in a ratio 1:2 connected with each other by strong O-H···O hydrogen bonds to form a two-dimensional network. Between these hydrogen-bonded layers, there are elongated cavities each containing two triiodide anions. The intermolecular I···I distance of the two enclosed triiodide anions is 3.6317(4)Å and should be considered as an interhalogen bonding interaction.

The title molecular salt, C6H16N+·CH3SO3 −, has been determined at 150 K. Two diisopropyl­ammonium cations (dipH) and two anions form N—H⋯O hydrogen-bonded cyclic dimers lying around centers of symmetry. Only two of the three O atoms of the methane­sulfonate anion are involved in hydrogen bonding, resulting in slightly longer S—O bond lengths. The title structure represents an example of a sulfonate anion that is part of a hydrogen-bonding R 4 4(12) graph-set motif, which is well known for related dipH acetates. Additionally, the Raman and the IR spectroscopic data for the title compound are presented.

Diisopropylammonium trifluoroacetate ({[iPr2NH2][CF3COO]}; dip tfa; 1) and diisopropylammonium pentafluoropropionate ({[iPr2NH2][C2F5COO]}; dip pfp; 2) have been synthesized and structurally characterized by X-ray diffraction and spectroscopic methods. Both compounds form hydrogen-bonded cyclic dimers (Etter symbol: R44 (12)) in the solid state. The asymmetric unit of 1 contains one trifluoroacetate anion and one dip cation in the centrosymmetric space group Pī. The asymmetric unit of 2 consists of two crystallographically independent pentafluoropropionate anions and two independent dip cations forming dimers in the form of rings, both lying around centers of symmetry in the space group Pī. In dip tfa and dip pfp the cations act as double hydrogen bond donors, and each of the two oxygen atoms of the carboxyl group are single hydrogen bond acceptors. The donor acceptor distances of the N-H...O hydrogen bonds are within the expected range for medium strong hydrogen bonds. The quasi-molecular cyclic dimers are connected with neighboring units only by van der Waals interactions.

C8H16Cl3NO2, monoclinic, P21 (no. 4), a = 9.1804(5), Å, b = 19.4133(10) Å, c = 13.9191(7) Å, β = 90.593(3)°, V = 2480.6(2) Å3, Z = 8, Rgt(F) = 0.0605, wRref(F2) = 0.1387, T = 296(2) K.