First hydrogen-bonded adduct of sterically hindered 2-tert-butyl-4-methyl-phenol (TBMP) with 1,3,6,8-tetra-aza-tri-cyclo-[4.4.1.13,8]dodecane (TATD) via coupling of classical hydrogen bonds and C-H⋯π non-covalent inter-actions.

The title compound, C8H16N4·2C11H16O, was synthesized from the corres-ponding sterically crowded phenol by treatment with the aminal cage polyamine. Single-crystal X-ray diffraction structural analysis revealed the three-mol-ecule aggregate to crystallize in the monoclinic space group P2/c with one half of a 1,3,6,8-tetra-aztri-cyclo-[4.4.1.13,8]dodecane (TATD) mol-ecule and one 2-tert-butyl-4-methyl-phenol mol-ecule per asymmetric unit. The crystal structure features inter-molecular O-H⋯N and C-H⋯O hydrogen bonds, as well as inter-molecular C-H⋯π inter-actions.

Synthesis and crystal structure of 2-(2-hy-droxy-phen-yl)-1,3-bis-(4-meth-oxy-benz-yl)-1,3-diazinan-5-ol.

The redetermined structure of 2-(2-hy-droxy-phen-yl)-1,3-bis-(4-meth-oxy-benz-yl)-1,3-diazinan-5-ol, C26H30N2O4, at 173 K has ortho-rhom-bic (Pbca) symmetry. It was previously described by Bolte et al. [ Private Communication (refcode EWICEV). CCDC, Cambridge, England]. The title compound resulted from the condensation reaction between 1,3-bis-{[(4-meth-oxy-phen-yl)meth-yl]amino}-propan-2-ol and 2-hy-droxy-benzaldehyde in CH3OH. The structure exhibits disorder. One of the 4-meth-oxy-benzyl groups, the hy-droxy group bonded to the 1,3-diazinan ring, and the methyl group of the meth-oxy residue are disordered over two orientations, with occupancies of 0.807 (3)/0.193 (3), 0.642 (5)/0.358 (5), and 0.82 (4)/0.18 (4), respectively. The dihedral angles between the mean planes of the central 1,3-diazinan-5-ol and the 4-meth-oxy-phenyl rings (both occupancy components of the disordered ring) are 88.65 (13), 85.79 (14) and 83.4 (7)°. The crystal packing is sustained by C-H⋯O and O-H⋯π inter-actions, giving rise to infinite chains running along the b-axis direction.

Mechanochemical synthesis and X-ray structural characterization of three 3-nitrophenol cocrystals with three aminal cage azaadamantanes: the role of the stereoelectronic effect on intermolecular hydrogen-bonding patterns.

The structures of the cocrystalline adducts of 3-nitrophenol (3-NP) with 1,3,5,7-tetraazatricyclo[3.3.1.13,7]decane [HMTA, (1)] as the 2:1:1 hydrate, 2C6H5NO3·C6H12N4·H2O, (1a), with 1,3,6,8-tetraazatricyclo[4.3.1.13,8]undecane [TATU (2)] as the 2:1 cocrystal, 2C6H5NO3·C7H14N4, (2a), and with 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane [TATD, (3)] as the 2:1 cocrystal, 2C6H5NO3·C8H16N4, (3a), are reported. In the binary crystals (2a) and (3a), the 3-nitrophenol molecules are linked via O-H...N hydrogen bonds into aminal cage azaadamantanes. In (1a), the structure is stabilized by O-H...N and O-H...O hydrogen bonds, and generates ternary cocrystals. There are C-H...O hydrogen bonds present in all three cocrystals, and in (1a), there are also C-H...O and C-H...π interactions present. The presence of an ethylene bridge in the structures of (2) and (3) defines the formation of a hydrogen-bonded motif in the supramolecular architectures of (2a) and (3a). The differences in the C-N bond lengths of the aminal cage structures, as a result of hyperconjugative interactions and electron delocalization, were analysed. These three cocrystals were obtained by the solvent-free assisted grinding method. Crystals suitable for single-crystal X-ray diffraction were grown by slow evaporation from a mixture of hexanes.

Crystal structure of the co-crystalline adduct 1,3,6,8-tetra-aza-tri-cyclo-[4.4.1.13,8]dodecane (TATD)-4-iodo-phenol (1/2): supra-molecular assembly mediated by halogen and hydrogen bonding.

The asymmetric unit of the title co-crystalline adduct, 1,3,6,8-tetra-aza-tri-cyclo[4.4.1.13,8]dodecane (TATD)-4-iodo-phenol (1/2), C8H16N4·2C6H5IO, comprises a half mol-ecule of the aminal cage polyamine plus a 4-iodo-phenol mol-ecule. A twofold rotation axis generates the other half of the adduct. The components are linked by two inter-molecular 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.

1,3-Bis{(E)-[4-(di-methyl-amino)-benzyl-idene]amino}-propan-2-ol: chain structure formation via an O-H⋯N hydrogen bond.

The asymmetric unit of the title compound, C21H28N4O, consists of two unique mol-ecules linked by an O-H⋯N hydrogen bond. The conformation of both C=N bonds is E and the azomethine functional groups lie close to the plane of their associated benzene rings in each of the independent mol-ecules. The dihedral angles between the two benzene rings are 83.14 (4) and 75.45 (4)°. The plane of the one of the N(CH3)2 units is twisted away from the benzene ring by 18.8 (2)°, indicating loss of conjugation between the lone electron pair and the benzene ring. In the crystal structure, O-H⋯N hydrogen bonds together with C-H⋯O hydrogen bonds link neighbouring supra-molecular dimers into a three-dimensional network.

Crystal structure of 2,2'-(ethane-1,2-di-yl)bis-(2,3-di-hydro-1H-naphtho-[1,2-e][1,3]oxazine): a prospective raw material for polybenzoxazines.

In the title compound, C26H24N2O2, the oxazine moiety is fused to a naphthalene ring system. The asymmetric unit consists of one half of the mol-ecule, which lies about an inversion centre. The C atoms of the ethyl-ene spacer group adopt an anti-periplanar arrangement. The oxazine ring adopts a half-chair conformation. In the crystal, supra-molecular chains running along the b axis are formed via short C-H⋯π contacts. The crystal studied was a non-merohedral twin with a fractional contribution of 0.168 (2) of the minor twin component.

C-I⋯N short contacts as tools for the construction of the crystal packing in the crystal structure of 3,3'-(ethane-1,2-di-yl)bis-(6-iodo-3,4-di-hydro-2H-1,3-benzoxazine).

The asymmetric unit of the title compound, C18H18I2N2O2, consists of one half-mol-ecule, completed by the application of inversion symmetry. The mol-ecule 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, mol-ecules 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 1,3-bis-[(E)-benzyl-idene-amino]-propan-2-ol.

In the title compound, C17H18N2O, the central carbon atom with the OH substituent and one of the (E)-benzyl-idene-amino substituents are disordered over two sets of sites with occupancies of 0.851 (4) and 0.149 (4). The relative positions of the two disorder components is equivalent to a rotation of approximately 60° about the C-N single bond. In the crystal, the mol-ecules are held together by O-H⋯N hydrogen bonds, forming simple C(5) chains along the b-axis direction. In addition, pairs of the chains are further aggregated by weak C-H⋯π inter-actions.

Crystal structure of 1,3-bis-[(E)-4-meth-oxy-benzyl-idene-amino]-propan-2-ol.

The title Schiff base, C19H22N2O3, was synthesized via the condensation reaction of 1,3-di-amino-propan-2-ol with 4-meth-oxy-benzaldehyde using water as solvent. The mol-ecule exists in an E,E conformation with respect to the C=N imine bonds and the dihedral angle between the aromatic rings is 37.25 (15)°. In the crystal, O-H⋯N hydrogen bonds link the mol-ecules into infinite C(5) chains propagating along the a-axis direction. The packing of these chains is consolidated by C-H⋯O inter-actions and C-H⋯π short contacts, forming a three-dimensional network.

Crystal structure of 1,3-bis-(3-tert-butyl-2-hy-droxy-5-methyl-benz-yl)-1,3-diazinan-5-ol monohydrate.

In the title hydrate, C28H42N2O3·H2O, the central 1,3-diazinan-5-ol ring adopts a chair conformation with the two benzyl substituents equatorial and the lone pairs of the N atoms axial. The dihedral angle between the aromatic rings is 19.68 (38)°. There are two intra-molecular O-H⋯N hydrogen bonds, each generating an S(6) ring motif. In the crystal, classical O-H⋯O hydrogen bonds connect the 1,3-diazinane and water mol-ecules into columns extending along the b axis. The crystal structure was refined as a two-component twin with a fractional contribution to the minor domain of 0.0922 (18).

Crystal structure of 1,2-bis-(6-bromo-3,4-dihydro-2H-benz[e][1,3]oxazin-3-yl)ethane: a bromine-containing bis-benzoxazine.

The title benzoxazine molecule, C18H18Br2N2O2, was prepared by a Mannich-type reaction of 4-bromo-phenol with ethane-1,2-di-amine and formaldehyde. The title compound crystallizes in the monoclinic space group C2/c with a centre of inversion located at the mid-point of the C-C bond of the central CH2CH2 spacer. The oxazinic ring adopts a half-chair conformation. The structure is compared to those of other functionalized benzoxazines synthesized in our laboratory. In the crystal, weak C-H⋯Br and C-H⋯O hydrogen bonds stack the mol-ecules along the b-axis direction.

Crystal structure of the 1:2 co-crystal of 1,3,6,8-tetra-aza-tri-cyclo-[4.3.1.13,8]undecane (TATU) and 4-chloro-phenol (1/2).

In the title compound, C7H14N4·2C6H5ClO, which crystallized with two crystallographically independent 4-chloro-phenol mol-ecules and one 1,3,6,8-tetra-aza-tri-cyclo-[4.3.1.13,8]undecane (TATU) mol-ecule in the asymmetric unit, the independent components are linked by two O-H⋯N hydrogen bonds. The hydrogen-bond acceptor sites are two non-equivalent N atoms from the aminal cage structure, and the tricyclic system distorts by changing the C-N bond lengths. In the crystal, these hydrogen-bonded aggregates are linked into chains along the c axis by C-H⋯N hydrogen bonds. The crystal structure also features C-H⋯π contacts.

Mechanochemical synthesis and crystal structure of a 1:2 co-crystal of 1,3,6,8-tetra-aza-tri-cyclo[4.3.1.13,8]undecane (TATU) and 4-chloro-3,5-dimethyl-phenol.

Solvent-free treatment of 1,3,6,8-tetra-aza-tri-cyclo-[4.3.1.13,8]undecano (TATU) with 4-chloro-3,5-di-methyl-phenol led to the formation of the title co-crystal, C7H14N4·2C8H9ClO. The asymmetric unit contains one aminal cage mol-ecule and two phenol mol-ecules 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 π-π stacking between the benzene rings from two different neighbouring phenol mol-ecules [centroid-centroid distance = 4.0570 (11) Å] consolidates the crystal packing.

Crystal structure and C-H⋯F hydrogen bonding in the fluorinated bis-benzoxazine: 3,3'-(ethane-1,2-di-yl)bis-(6-fluoro-3,4-di-hydro-2H-1,3-benzoxazine).

The title fluorinated bis-benzoxazine, C18H18F2N2O2, crystallizes with one half-mol-ecule in the asymmetric unit, which is completed by inversion symmetry. The fused oxazine ring adopts an approximately half-chair conformation. The two benzoxazine rings are oriented anti to one another around the central C-C bond. The dominant inter-molecular inter-action in the crystal structure is a C-H⋯F hydrogen bond between the F atoms and the axial H atoms of the OCH2N methyl-ene group in the oxazine rings of neighbouring mol-ecules. C-H⋯π contacts further stabilize the crystal packing.

Crystal structure of the 1,3,6,8-tetra-aza-tri-cyclo[4.3.1.1(3,8)]undecane (TATU)-4-nitro-phenol (1/2) adduct: the role of anomeric effect in the formation of a second hydrogen-bond inter-action.

In the title ternary co-crystalline adduct, C7H14N4·2C6H5NO3, mol-ecules are linked by two inter-molecular O-H⋯N hydrogen bonds, forming a tricomponent aggregates in the asymmetric unit. The hydrogen-bond formation to one of the N atoms is enough to induce structural stereoelectronic effects in the normal donor→acceptor direction. In the title adduct, the two independent nitro-phenol mol-ecules are essentially planar, with maximum deviations of 0.0157 (13) and 0.0039 (13) Å. The dihedral angles between the planes of the nitro group and the attached benzene rings are 4.04 (17) and 5.79 (17)°. In the crystal, aggregates are connected by C-H⋯O hydrogen bonds, forming a supra-molecular dimer enclosing an R 6 (6)(32) ring motif. Additional C-H⋯O inter-molecular hydrogen-bonding inter-actions form a second supra-molecular inversion dimer with an R 2 (2)(10) motif. These units are linked via C-H⋯O and C-H⋯N hydrogen bonds, forming a three-dimensional network.

Crystal structure of 1-[(2,3-dihydro-1H-naphtho-[1,2-e][1,3]oxazin-2-yl)meth-yl]naphthalen-2-ol: a possible candidate for new polynaphthoxazine materials.

In the title compound, C23H19NO2, an oxazine Mannich base derivative, the oxazine ring has a half-chair conformation. The 2-hy-droxy-naphthalen-1-yl substituent is placed in an axial position. There is an intra-molecular O-H⋯N hydrogen bond, forming an S(6) graph-set motif. In the crystal, mol-ecules are connected by a pair of C-H⋯π inter-actions into an inversion dimer, which is reinforced by another pair of weak C-H⋯π inter-actions. The dimers are linked by a π-π inter-action [centroid-centroid distance = 3.6268 (17) Å], consolidating a column along the a axis. Furthermore, the columns inter-act with each other by a weak C-H⋯π inter-action, generating a three-dimensional network.

Crystal structure of the co-crystalline adduct 1,3,6,8-tetra-aza-tri-cyclo-[4.4.1.1(3,8)]dodecane (TATD)-4-chloro-3,5-di-methyl-phenol (1/1).

In the crystal of the title co-crystalline adduct, C8H16N4·C8H9ClO, (I), prepared by solid-state reaction, the mol-ecules are linked by inter-molecular O-H⋯N hydrogen bonds, forming a D motif. The aza-adamantane 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 D 2d mol-ecular symmetry in the tetra-aza-tri-cyclo 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 mol-ecules are not only linked by a classical O-H⋯N hydrogen bond but are further connected by weak C-H⋯π inter-actions, forming a two-dimensional supra-molecular network parallel to the bc plane.

Crystal structure of the co-crystalline adduct 1,3,6,8-tetra-aza-tri-cyclo-[4.4.1.1(3,8)]dodecane (TATD)-4-bromo-phenol (1/2).

The structure of the 1:2 co-crystalline adduct C8H16N4·2C6H5BrO, (I), from the solid-state reaction of 1,3,6,8-tetra-aza-tri-cyclo-[4.4.1.1(3,8)]dodecane (TATD) and 4-bromo-phenol, has been determined. The asymmetric unit of the title co-crystalline adduct comprises a half mol-ecule of aminal cage polyamine plus a 4-bromo-phenol mol-ecule. A twofold rotation axis generates the other half of the adduct. The primary inter-species association in the title compound is through two inter-molecular 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 supra-molecular structure parallel to the bc plane.

Crystal structure of 1,1'-[imidazolidine-1,3-diylbis(methyl-ene)]bis-(naphthalen-2-ol).

The crystal structure of the title compound, C25H24N2O2, at 173 K has monoclinic (C2/c) symmetry. The mol-ecule is located on a crystallographic twofold rotation axis with only half a mol-ecule in the asymmetric unit. The imidazolidine ring adopts a twist conformation, with a twist about the ring C-C bond. The crystal structure shows the anti-clinal disposition of the two (2-hy-droxy-naphthalen-1-yl)methyl substituents of the imidazolidine ring. The structure displays two intra-molecular O-H⋯N hydrogen bonds, each forming an S(6) ring motif.

Evidence for stereoelectronic effects in the N-C-N group of 8,10,12-triaza-1-azoniatetracyclo[8.3.1.1(8,12).0(2,7)]pentadecane 4-nitrophenolate 4-nitrophenol monosolvate from the protonation of aminal (2R,7R)-1,8,10,12-tetraazatetracyclo[8.3.1.1(8,12).0(2,7)]pentadecane: X-ray and natural bond orbital analysis.

The title molecular salt, C11H21N4(+)·C6H4NO3(-)·C6H5NO3, (II), crystallizes with two independent three-component aggregates in the asymmetric unit. In the cations, the cyclohexane rings fused to the cage azaadamantane systems both adopt a chair conformation. In the crystal structure, the aggregates are connected by C-H···O hydrogen bonds, forming a supramolecular unit enclosing an R4(4)(24) ring motif. These units are linked via C-H···O and C-H···N hydrogen bonds, forming a three-dimensional network. Even hydrogen-bond formation to one of the N atoms is enough to induce structural stereoelectronic effects in the normal donor→acceptor direction. The C-N bond distances provide structural evidence for a strong anomeric effect. The structure also displays O-H···O and N-H···O hydrogen bonding. Geometric optimization and natural bond orbital (NBO) analysis of (II) were undertaken by utilizing DFT/B3LYP with the 6-31+G(d,p) basis set. NBO second-order perturbation theory calculations indicate donor-acceptor interactions between nitrogen lone pairs and the antibonding orbital of the C-C and C-N bonds for the protonated polyamine, in agreement with the occurrence of bond-length and bond-angle changes within the aminal cage structure.