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The asymmetric unit of the title compound, C21H28N4O, consists of two unique molecules 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 molecules. 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 supramolecular dimers into a three-dimensional network.
The title co-crystal, 1,3,5,7-tetraazatricyclo[3.3.1.13,7]decane (HMTA, 1)–4-fluorophenol (4-FP) (1/1), C6H12N4·C6H5FO, shows an unusual asymmetric unit that comprises eight independent molecules (Z′′ = 8), four for each component, with four formula units per asymmetric unit (Z′ = 4). In the molecular packing, each HMTA molecule bridges one 4-FP molecule via an O−H···N hydrogen bond to form a two-molecule aggregate. Differences can be observed between the bond lengths and angles of the independent HMTA and 4-FP molecules and those of the molecules in the aggregate. The C−N bonds exhibit different bond lengths in the tetrahedral cage-like structure of the HMTA molecules, but the largest differences between the molecular aggregates are in the bond lengths in the 4-fluorophenol ring. In the crystal, the HMTA and 4-FP molecules form two hydrogen-bonded (O−H···N, C−H···F and C−H···O) dimers of HMTA and 4-FP molecules, A···D and B···C inversion dimers, which generate enlarged R88(34) ring motifs in both supramolecular structures. In both structures, the crystal packing also features additional C−H···F and C−H···O interactions. The A···D and B···C dimers are linked by additional C−H···F and C−H···O hydrogen bonds, forming columns along the a and b axes, respectively. The importance of the C−H···F interaction to the structure and crystal packing has been demonstrated.
The title fluorinated bisbenzoxazine, C18H18F2N2O2, crystallizes with one half-molecule 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 intermolecular interaction in the crystal structure is a C-H...F hydrogen bond between the F atoms and the axial H atoms of the OCH2N methylene group in the oxazine rings of neighbouring molecules. C-H...[pi] contacts further stabilize the crystal packing.
The crystal structure of the title compound, C25H24N2O2, at 173 K has monoclinic (C2/c) symmetry. The molecule is located on a crystallographic twofold rotation axis with only half a molecule 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 anticlinal disposition of the two (2-hydroxynaphthalen-1-yl)methyl substituents of the imidazolidine ring. The structure displays two intramolecular O—H⋯N hydrogen bonds, each forming an S(6) ring motif.
The title benzoxazine molecule, C18H18Br2N2O2, was prepared by a Mannich-type reaction of 4-bromophenol with ethane-1,2-diamine 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 molecules along the b-axis direction.
Crystal structure of 1,3-bis(3-tert-butyl-2-hydroxy-5-methylbenzyl)-1,3-diazinan-5-ol monohydrate
(2016)
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 intramolecular 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 molecules 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).
The title Schiff base, C19H22N2O3, was synthesized via the condensation reaction of 1,3-diaminopropan-2-ol with 4-methoxybenzaldehyde using water as solvent. The molecule 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 molecules into infinite C(5) chains propagating along the a-axis direction. The packing of these chains is consolidated by C-H...O interactions and C-H...[pi] short contacts, forming a three-dimensional network.
In the title compound, C17H18N2O, the central carbon atom with the OH substituent and one of the (E)-benzylideneamino 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 molecules 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 interactions.
In the title compound, C23H19NO2, an oxazine Mannich base derivative, the oxazine ring has a half-chair conformation. The 2-hydroxynaphthalen-1-yl substituent is placed in an axial position. There is an intramolecular O-H...N hydrogen bond, forming an S(6) graph-set motif. In the crystal, molecules are connected by a pair of C-H...[pi] interactions into an inversion dimer, which is reinforced by another pair of weak C-H...[pi] interactions. The dimers are linked by a [pi]-[pi] interaction [centroid-centroid distance = 3.6268 (17) Å], consolidating a column along the a axis. Furthermore, the columns interact with each other by a weak C-H...[pi] interaction, generating a three-dimensional network.
In the title compound, C26H24N2O2, the oxazine moiety is fused to a naphthalene ring system. The asymmetric unit consists of one half of the molecule, which lies about an inversion centre. The C atoms of the ethylene spacer group adopt an antiperiplanar arrangement. The oxazine ring adopts a half-chair conformation. In the crystal, supramolecular 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.
In the title ternary co-crystalline adduct, C7H14N4·2C6H5NO3, molecules are linked by two intermolecular 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 nitrophenol molecules 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 supramolecular dimer enclosing an R66(32) ring motif. Additional C—H⋯O intermolecular hydrogen-bonding interactions form a second supramolecular inversion dimer with an R22(10) motif. These units are linked via C—H⋯O and C—H⋯N hydrogen bonds, forming a three-dimensional network.
In the title compound, C7H14N4·2C6H5ClO, which crystallized with two crystallographically independent 4-chlorophenol molecules and one 1,3,6,8-tetraazatricyclo[4.3.1.13,8]undecane (TATU) molecule 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...[pi] contacts.
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.
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.
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.
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.
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.
The title compound, C8H16N4·2C11H16O, was synthesized from the corresponding sterically crowded phenol by treatment with the aminal cage polyamine. Single-crystal X-ray diffraction structural analysis revealed the three-molecule aggregate to crystallize in the monoclinic space group P2/c with one half of a 1,3,6,8-tetraaztricyclo[4.4.1.13,8]dodecane (TATD) molecule and one 2-tert-butyl-4-methylphenol molecule per asymmetric unit. The crystal structure features intermolecular O—H...N and C—H...O hydrogen bonds, as well as intermolecular C—H...π interactions.
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.
Synthesis and crystal structure of 2-(2-hydroxyphenyl)-1,3-bis(4-methoxybenzyl)-1,3-diazinan-5-ol
(2022)
The redetermined structure of 2-(2-hydroxyphenyl)-1,3-bis(4-methoxybenzyl)-1,3-diazinan-5-ol, C26H30N2O4, at 173 K has orthorhombic (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-methoxyphenyl)methyl]amino}propan-2-ol and 2-hydroxybenzaldehyde in CH3OH. The structure exhibits disorder. One of the 4-methoxybenzyl groups, the hydroxy group bonded to the 1,3-diazinan ring, and the methyl group of the methoxy 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-methoxyphenyl 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 interactions, giving rise to infinite chains running along the b-axis direction.
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.