Trimethylammonium perchlorate at 97 K

Gotoh, Kazuma; Ishikawa, Rie; Ishida, Hiroyuki

doi:10.1107/s1600536806007987

Cited by 1 publication

(2 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…12 In the 0-3 range for ΔpK a it is difficult to predict whether proton transfer will occur or not. pyrazine, 18 pyrimidine, 19 cytosine, 20 benzamidazole, 21 imidazole 22 ). 14 In this context chloranilic acid (2,5-dichloro-3,6-dihydroxybenzoquinone) shows a high propensity for proton transfer and charge-assisted hydrogen bond formation and hence is a useful molecular component for crystal engineering studies.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

High resolution X-ray and neutron diffraction studies on molecular complexes of chloranilic acid and lutidines

et al. 2016

View full text Add to dashboard Cite

A total of 18 molecular complexes of chloranilic acid (H 2 CA) and various isomeric dimethylpyridine (lutidine) bases (B) in a 1 : 1 and 1 : 2 stoichiometric ratio have been prepared and characterised structurally; 10 of the structural determinations used high resolution crystallography. Since proton transfer between the acid and base occurs in all the crystalline forms, they are most appropriately described as salts between the lutidinium cations [BH + ] and the chloranilate mono-and dianions [HCA − ] and [CA 2− ]. The formation of bifurcated or non-bifurcated charge-assisted hydrogen bonds is described and the influence of the different functional groups on symmetrical or asymmetrical bifurcated hydrogen bond formation are investigated. Previously unreported salts of the composition [BH + ]ĳHCA − ] with 2,3-and 3,5-lutidine, and [BH + ] 2 [CA 2− ] with 2,3-, 2,4-, 2,5-, 2 ,6-and 3,4-lutidine are reported, as well as di-and trihydrate forms of the latter salt type with 2,4-and 3,4-lutidine respectively. For the 2,4-and 3,5-lutidines only, molecular complexes containing co-existing charged and neutral chloranilic acid molecules are also observed. The charge delocalisation in the chloranilate anions, which has an influence on the hydrogen bond distances, is confirmed by the deformation density plots, atomic net charge calculations and the density at the bond critical points. The QTAIM molecular graphs, which show the presence of bifurcated or non-bifurcated hydrogen bonds, are highly dependent on the exact refinement model. Lattice energy calculations based on the experimental charge densities also show a high dependence on the refinement strategy, while theoretical lattice energy calculations using different approaches provide no consistency in the rank order stabilities. We conclude that neither experimental nor theoretical approaches are currently sufficiently accurate to determine a definitive stability order for such isomeric complexes. CrystEngCommThis journal is

show abstract

Section: Introductionmentioning

confidence: 99%

“…picolines, 15,16 4,4′-bipyridine 17 ) or heterocyclic rings incorporating more than one N atom (e.g. pyrazine, 18 pyrimidine, 19 cytosine, 20 benzamidazole, 21 imidazole 22 ). In these examples, proton transfer from chloranilic acid to the nitrogen base frequently occurs in the solid-state.…”

Section: Introductionmentioning

confidence: 99%