Crystal structure, quantum mechanical investigation, IR and NMR spectroscopy of two new organic perchlorates: (C6H18N3)•(ClO4)3H2O(I) and (C9H11N2)•ClO4(II)

The reaction of perchloric acid with 1-(2-aminoethyl)piperazine or 5,6-dimethyl-benzimidazole results in the formation of 1-(2-amonioethyl)piperazine-1,4-dium triperchlorate hydrate (C6H18N3)center dot(ClO4)(3)center dot H2O (I) or 5,6-dimethyl-benzylimidazolium perchlorate (C9H11N2)center dot ClO4 (II). Both compounds were fully structurally characterized including single crystal X-ray diffraction analysis. Compound (I) crystallizes in the centrosymmetric triclinic space group P (1) over bar with the lattice parameters a = 7.455 (2), b = 10.462 (2), c = 10.824 (2) angstrom, alpha = 80.832 (2), beta = 88.243 (2), gamma = 88.160 (2)degrees, Z = 2 and V = 832.77 (3) angstrom(3). Compound (H) has been found to belong to the P2(1)/c space group of the monoclinic system, with a = 7.590 (3), b = 9.266 (3), c = 16.503 (6) angstrom, beta = 107.38 (2)degrees, V = 1107.69 (7) angstrom(3) and Z = 4. The structures of (I) and (H) consist of slightly distorted [ClO4](-) tetrahedra anions and 1-(2-amonioethyl)piperazine-1,4-dium trication (I) or 5,6-dimethyl-benzylimidazolium cations (II) and additionally a lattice water in (I). The crystal structures of (I) and (II) exhibit complex three-dimensional networks of H-bonds connecting all their components. In the atomic arrangement of (I), the ClO4- anions form corrugated chains, while in (II) the atomic arrangement exhibits wide pseudo-hexagonal channels of ClO4 tetrahedra including the organic entities. The lattice water serves as a link between pairs of cations and pairs of anions via several O-H center dot center dot center dot O and N-H center dot center dot center dot O interactions in compound (I). The vibrational absorption bands were identified by infrared spectroscopy. These compounds were also investigated by solid-state C-13, Cl-35 and N-15 NMR spectroscopy. OFF calculations allowed the attribution of the IR and NMR bands. Intermolecular interactions were investigated by Hirshfeld surfaces. Electronic properties such as HOMO and LUMO energies were derived. (C) 2018 Elsevier B.V. All rights reserved.