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The structure of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate 1 has been studied by X-ray diffraction, B3LYP/6–311G(d,p) calculations, FTIR, Raman and NMR spectroscopic techniques. The crystal is polar in monoclinic space group Cc. Two 4-trimethylammoniumbenzoate moieties are joined by a short and asymmetric hydrogen bond of 2.45(2) Å. Water molecules are gradually released from the structure, causing shifts in the position of iodine anions, which induces their disorder. The water molecule interacts with 4-trimethylammoniumbenzoate moiety and iodide anion via two O(3)–H(1)⋯O(1) and O(3)–H(2)⋯I(1) hydrogen bonds of lengths 2.70(3) and 3.51(1) Å. Hydrogen bonds in theoretically predicted structures of 2 and 3 (in vacuum), and 4 , 5 (in DMSO) optimized by the B3LYP/6-311G(d,p) approach are slightly longer than in crystal 1 . The FTIR spectrum of 1 shows a broad and intense absorption in the 1500–400 cm −1 region, typical of short hydrogen bonds assigned to the ν as (OHO) + γ (OHO) vibrations. The correlations between the experimental 13 C and 1 H chemical shifts ( δ exp ) of the investigated compound in DMSO and the GIAO/B3LYP/6-311G(d,p) magnetic isotropic shielding constants ( σ calc ) calculated by using the screening solvation model (COSMO) are linear, δ exp = a + b σ calc , and they well reproduce the experimental chemical shifts. [ABSTRACT FROM AUTHOR]

The 1:2 complex ( 1 ) of dimethylphenyl betaine (DMPB) with two molecules of 2,6-dichloro-4-nitro-phenol (DCNP) was prepared and characterized by X-ray diffraction, B3LYP/6-311++G(d,p) and B3LYP-D3/6-311++G(d,p)calculations, FTIR and NMR spectroscopies. The crystal is monoclinic, space group P 2 1 / c with Z = 4. The protons at the oxygen atoms of phenols are bonded to each oxygen atoms of the DMPB carboxylate group by two nonequivalent H-bonds with the O H⋯O distances of 2.473(5) and 2.688(4) Å. Both H-bonds in the optimized structures 2 (in vacuum), 3 (in DMSO solution) and dispersion-correlated functional (D3) 4 (in vacuum) are comparable and are slightly shorter than O(6) H(O6)⋯O(2) in the crystal. The FTIR spectrum of 1 shows a broad absorption in the 3400–2000 cm −1 region corresponding to a longer hydrogen bond and a broad absorption in the 1800–500 cm −1 region caused by the shorter H-bond. The relations between the experimental 13 C and 1 H chemical shifts ( δ exp ) of the investigated compound 1 in DMSO solution and GIAO/B3LYP/6-311++G(d,p) magnetic isotropic shielding constants ( σ calc ) obtained by using the screening solvation model (COSMO) for 3 are linear and reproduce well the experimental chemical shifts described by the equation: δ exp = a + b σ calc . [ABSTRACT FROM AUTHOR]