From extraction experiments and gamma-activity measurements, the extraction constan corresponding to the equilibrium NH4(+)(aq) + 1*Na(+)(nb) <=> 1*NH4(+)(nb) + Na(+)(aq) taking place in the two-phase water - nitrobenzene system (1 = dibenzo-18-crown-6, aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K(ex) (NH4(+),1*Na(+)) = -0.1 +/- 0.1. Further, the stability constant of the...

The laser-induced fluorescence spectra of jet-cooled benzo-18-crown-6 (B18C6) and dibenzo-18-crown-6 (DB18C6) exhibit a number of vibronic bands in the 35 000-37 000 cm(-1) region. We attribute these bands to monomers and hydrated clusters by fluorescence-detected IR-UV and UV-UV double resonance spectroscopy. We found four and two conformers for bare B18C6 and DB18C6, and the hydration of one ...

In the title compound, C(6)H(7)ClN(+)·BF(4) (-)·C(12)H(24)O(6), the complete cation is generated by crystallographic mirror symmetry, with two C atoms and the N and Cl atoms lying on the mirror plane. The complete crown ether is also generated by mirror symmetry, as is the anion (in which the B and two F atoms lie on the mirror plane). The -NH(3) (+) group of the cation inserts into the crown-e...

In the title compound, C(6)H(7)IN(+)·ClO(4) (-)·C(12)H(24)O(6), the proton-ated 4-iodo-anilinium cation inter-acts with the 18-crown-6 through three N-H⋯O hydrogen bonds, forming a rotator-stator-like structure. The cation, anion and 18-crown-6 mol-ecule all have crystallographically imposed mirror symmetry.

In the title compound, C(6)H(5)Cl(3)N(+)·ClO(4) (-)·C(12)H(24)O(6), the perchlorate anion is disordered over two orientations in a 0.666 (17):0.334 (17) ratio. The ammonium group of the organic cation inserts into the crown ether ring and forms three bifurcated N-H⋯(O,O) hydrogen bonds to generate a supra-molecular complex. The macrocycle has approximate D(3d) local symmetry.