Propane-1,3-diaminium bis(perchlorate)–18-crown-6 (1/2)

In the title compound, C3H12N2 2+·2ClO4 −·2C12H24O6, the central C atom of the propane-1,3-diammonium cation is located on a twofold rotation axis and the two terminal –NH3 groups insert into the crown rings through N—H⋯O hydrogen bonding, resulting in the formation of a 1:2 supramolecular [(C3H12N2)·(C12H24O6)2]+ complex. The perchlorate anion links with the supramolecular complex via weak C—H⋯O hydrogen bonding.

In the title compound, C 3 H 12 N 2 2+ Á2ClO 4 À Á2C 12 H 24 O 6 , the central C atom of the propane-1,3-diammonium cation is located on a twofold rotation axis and the two terminal -NH 3 groups insert into the crown rings through N-HÁ Á ÁO hydrogen bonding, resulting in the formation of a 1:2 supramolecular [(C 3 H 12 N 2 )Á(C 12 H 24 O 6 ) 2 ] + complex. The perchlorate anion links with the supramolecular complex via weak C-HÁ Á ÁO hydrogen bonding.

Comment
Organic amino compounds attracted more attention as phase transition dielectric materials for its application in memory storage (Fu et al., 2007;Fu & Xiong, 2008;Fu et al., 2008;Fu et al., 2009). With the purpose of obtaining phase transition crystals of amino compounds, various amines have been studied and we have elaborated a series of new materials with this organic molecules (Fu et al., 2011a;Fu et al., 2011b;Fu et al., 2011c). In this study, we describe the crystal structure of the title compound, bis(18-crown-6)propane-1,3-diammonium perchlorate . The title compound was stabilized by intermolecular N-H···O hydrogen bonds, the ClO 4 anion not participating in the H-bonding interactions. The intermolecular N-H···O H-bonding length are within the usual range of 2.951 (5) to 3.152 (5)Å. (Table 1 and Fig.2).
The dielectric constant of title compound as a function of temperature indicates that the permittivity is basically temperature-independent, suggesting that this compound should be not a real ferroelectrics or there may be no distinct phase transition occurred within the measured temperature range. Similarly, below the melting point (405 K) of the compound, the dielectric constant as a function of temperature also goes smoothly, and there is no dielectric anomaly observed (dielectric constant ranging from 4.2 to 7.5).
supplementary materials sup-2 Refinement All H atoms attached to C atoms were fixed geometrically and treated as riding with 0.97 Å (C-methylene). The positional parameters of the H atoms (N1) were initially refined freely, subsequently restrained using a distance of N-H = 0.89 (2) Å, and in the final refinements treated in riding motion of their parent nitrogen atom with U iso (H)=1.5U eq (N). Fig. 1. A view of the title compound with the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.