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- crystal structure (19)
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- The role of hyperconjugation on the structure and c–h stretching frequencies of 3,3′-ethane-1,2-diyl- bis-1,3,5-triazabicyclo[3.2.1]octane (etaboc): An x-ray structure and vibrational study (2018)
- Structural and vibrational studies have been carried out for the most stable conformer of 3,3′-ethane-1,2-diyl-bis-1,3,5-triazabicyclo[3.2.1]octane (ETABOC) at the DFT/B3LYP/6-31G(dp) level using the Gaussian 03 software. In light of the computed vibrational parameters, the observed IR Bolhmann bands for the C2V, C2, and Ci symmetrical structures of ETABOC have been analyzed. Hyperconjugative interaction was done by Natural Bond Orbital Analysis. Interpretation of hyperconjugative interaction involving the lone pairs on the bridgehead nitrogen atoms with the neighboring C–N and C–C bonds defines the conformational preference of the title compound. The recorded X-ray diffraction bond parameters were compared with theoretical values calculated at B3LYP/6-31G(d,p) and HF/6-31G(d,p) level of theory showed that ETABOC adopts a chair conformation and possesses an inversion center.
- Redetermination of 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (2014)
- The structure of the title compound, C8H16N4, which consists of four fused seven-membered rings, has been redetermined at 173 K. This redetermination corrects the orientation of two H atoms, which were located at unrealistic positions in the original room-temperature study [Murray-Rust (1974[Murray-Rust, P. (1974). J. Chem. Soc. Perkin Trans. 2, pp. 1136-1141.]). J. Chem. Soc. Perkin Trans. 2, pp. 1136–1141]. The complete molecule is generated by -42m symmetry, with one quarter of a molecule [one N atom (site symmetry m), two C atoms (one with site symmetry m and the other with site symmetry 2) and two H atoms] in the asymmetric unit. No directional interactions beyond van der Waals contacts are apparent in the crystal structure.
- rac-4-Chloro-2-[({2-[(3-chloro-6-hydroxy-2,4-dimethylbenzyl)(methyl)amino]propyl}(methyl)amino)methyl]-3,5-dimethylphenol (2012)
- The title compound, C23H32Cl2N2O2, a potential chiral ligand for coordination chemistry, was prepared by a two-step reaction. The molecule is located on a crystallographic centre of inversion. As a result, the methyl group bonded to the methylene group is disordered over two equally occupied positions, sharing the same site as the H atom of the chiral C atom. As a further consequence of the crystallographic centrosymmetry, the 1,2-diaminopropane unit adopts an antiperiplanar conformation and the two benzene rings are coplanar. The central chain is in an all-trans arrangement. An intramolecular O-H...N hydrogen bond makes an S(6) ring motif. A C-H...[pi] interaction links the molecules into one-dimensional chains along the [001] direction.
- Mechanochemical synthesis of a cocrystal of two supramolecular hydrogen-bonded aggregates of 1,3,6,8-tetraazatricyclo[4.3.1.13,8]undecane (tatu) with 4-tert-butylphenol bearing different hydrogen bonding interactions (2018)
- The synthesis and single crystal structure of a new cocrystal, which is composed of OHphenolic∙∙∙OHphenolic∙∙∙Naminalic supramolecular heterosynthons assembled from 4-tert-butylphenol and the macrocyclic aminal TATU, is presented. This cocrystal was prepared by solvent-free assisted grinding, which is a commonly used mechanochemical method. Crystal structure, supramolecular assembly through hydrogen bonding interactions as well as the physical and spectroscopic properties of the title cocrystal are presented in this paper.
- Mechanochemical synthesis and crystal structure of a 1:2 co-crystal of 1,3,6,8-tetraazatricyclo-[4.3.1.13,8]undecane (TATU) and 4-chloro-3,5-dimethylphenol (2016)
- Solvent-free treatment of 1,3,6,8-tetraazatricyclo[4.3.1.13,8]undecano (TATU) with 4-chloro-3,5-dimethylphenol led to the formation of the title co-crystal, C7H14N4·2C8H9ClO. The asymmetric unit contains one aminal cage molecule and two phenol molecules linked via two O-H...N hydrogen bonds. In the aminal cage, the N-CH2-CH2-N unit is slightly distorted from a syn periplanar geometry. Aromatic [pi]-[pi] stacking between the benzene rings from two different neighbouring phenol molecules [centroid-centroid distance = 4.0570 (11) Å] consolidates the crystal packing.
- C—IN short contacts as tools for the construction of the crystal packing in the crystal structure of 3,30-(ethane-1,2-diyl)bis(6-iodo-3,4-dihydro-2H-1,3-benzoxazine) (2017)
- The asymmetric unit of the title compound, C18H18I2N2O2, consists of one half-molecule, completed by the application of inversion symmetry. The molecule adopts the typical structure for this class of bis-benxozazines, characterized by an anti orientation of the two benzoxazine rings around the central C—C bond. The oxazinic ring adopts a half-chair conformation. In the crystal, molecules are linked by C—I⋯N short contacts [I⋯N = 3.378 (2) Å], generating layers lying parallel to the bc plane.
- Crystal structure of the di-Mannich base 4,4′-dichloro-3,3′,5,5′-tetramethyl-2,2′-[imidazolidine-1,3-diylbis(methylene)]diphenol (2015)
- The title compound, C21H26Cl2N2O2, was prepared in a solvent-free microwave-assisted synthesis, and crystallizes in the orthorhombic space group Pna21. The imidazolidine ring adopts an envelope conformation and its mean plane is almost perpendicular to the two pendant aromatic rings [dihedral angles = 84.61 (9) and 86.54 (9)°]. The molecular structure shows the presence of two intramolecular O—H⋯N hydrogen bonds between the phenolic hydroxy groups and imidazolidine N atoms. The two 3-chloro-6-hydroxy-2,4-dimethylbenzyl groups are located in a cis orientation with respect to the imidazolidine fragment. As a result, the lone pairs of electrons on the N atoms are presumed to be disposed in a syn conformation. This is therefore the first example of an exception to the `rabbit-ears' effect in such 2,2′-[imidazolidine-1,3-diylbis(methylene)]diphenol derivatives.
- Crystal structure of the co-crystalline adduct 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD)–4-iodophenol (1/2) : supramolecular assembly mediated by halogen and hydrogen bonding (2017)
- The asymmetric unit of the title co-crystalline adduct, 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD)–4-iodophenol (1/2), C8H16N4·2C6H5IO, comprises a half molecule of the aminal cage polyamine plus a 4-iodophenol molecule. A twofold rotation axis generates the other half of the adduct. The components are linked by two intermolecular O—H⋯N hydrogen bonds. The adducts are further linked into a three-dimensional framework structure by a combination of N⋯I halogen bonds and weak non-conventional C—H⋯O and C—H⋯I hydrogen bonds.
- Crystal structure of the co-crystalline adduct 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD)–4-chloro-3,5-dimethylphenol (1/1) (2015)
- In the crystal of the title co-crystalline adduct, C8H16N4·C8H9ClO, (I), prepared by solid-state reaction, the molecules are linked by intermolecular O—H⋯N hydrogen bonds, forming a D motif. The azaadamantane structure in (I) is slightly distorted, with N—CH2—CH2—N torsion angles of 10.4 (3) and −9.0 (3)°. These values differ slightly from the corresponding torsion angles in the free aminal cage (0.0°) and in related co-crystalline adducts, which are not far from a planar geometry and consistent with a D2d molecular symmetry in the tetraazatricyclo structure. The structures also differ in that there is a slight elongation of the N—C bond lengths about the N atom that accepts the hydrogen bond in (I) compared with the other N—C bond lengths. In the crystal, the two molecules are not only linked by a classical O—H⋯N hydrogen bond but are further connected by weak C—H⋯π interactions, forming a two-dimensional supramolecular network parallel to the bc plane.
- Crystal structure of the co-crystalline adduct 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD)–4-bromophenol (1/2) (2015)
- The structure of the 1:2 co-crystalline adduct C8H16N4·2C6H5BrO, (I), from the solid-state reaction of 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD) and 4-bromophenol, has been determined. The asymmetric unit of the title co-crystalline adduct comprises a half molecule of aminal cage polyamine plus a 4-bromophenol molecule. A twofold rotation axis generates the other half of the adduct. The primary inter-species association in the title compound is through two intermolecular O—H⋯N hydrogen bonds. In the crystal, the adducts are linked by weak non-conventional C—H⋯O and C—H⋯Br hydrogen bonds, giving a two-dimensional supramolecular structure parallel to the bc plane.
