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Crystal structures of 1,4-di-aza-bicyclo-[2.2.2]octan-1-ium 4-nitro-benzoate dihydrate and 1,4-di-aza-bicyclo-[2.2.2]octane-1,4-diium bis-(4-nitro-benzoate): the influence of solvent upon the stoichiometry of the formed salt.

Akhmad Aznan AM, Abdullah Z, Tiekink ER - Acta Crystallogr Sect E Struct Rep Online (2014)

Bottom Line: The global crystal structure comprises alternating layers of water mol-ecules and ion pairs stacked along the c axis.In the crystal of (2), the three-ion aggregates are assembled into a three-dimensional architecture by a large number of methyl-ene-carboxyl-ate/nitro C-H⋯O inter-actions as well as π-π contacts between inversion-related benzene rings [inter-centroid distances = 3.5644 (16) and 3.6527 (16) Å].The cations and anions assemble into alternating layers along the c axis.

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Affiliation: Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.

ABSTRACT
The 1:1 co-crystallization of 1,4-di-aza-bicyclo-[2.2.2]octane (DABCO) with 4-nitro-benzoic acid in ethanol-water (3/1) gave the salt dihydrate C6H13N2 (+)·C7H4NO4 (-)·2H2O, (1), whereas from methanol, the salt C6H14N2 (2+)·2C7H4NO4 (-), (2), was isolated. In (1), the cation and anion are linked by a strong N-H⋯O hydrogen bond, and the carboxyl-ate anion is close to planar [dihedral angle between terminal residues = 6.83 (9)°]. In (2), a three-ion aggregate is assembled by two N-H⋯O hydrogen bonds, and the carboxyl-ate anions are again close to planar [dihedral angles between terminal residues = 1.7 (3) and 5.9 (3)°]. Through the inter-vention of solvent water mol-ecules, which self-assemble into helical supra-molecular chains along the b axis, the three-dimensional architecture in (1) is stabilized by water-DABCO O-H⋯N and water-carboxyl-ate O-H⋯O hydrogen bonds, with additional stability afforded by C-H⋯O inter-actions. The global crystal structure comprises alternating layers of water mol-ecules and ion pairs stacked along the c axis. In the crystal of (2), the three-ion aggregates are assembled into a three-dimensional architecture by a large number of methyl-ene-carboxyl-ate/nitro C-H⋯O inter-actions as well as π-π contacts between inversion-related benzene rings [inter-centroid distances = 3.5644 (16) and 3.6527 (16) Å]. The cations and anions assemble into alternating layers along the c axis.

No MeSH data available.


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Unit-cell contents shown in projection down the a axis for (2). The N—H⋯O and C—H⋯O hydrogen bonds are shown as blue and green dashed lines, respectively (see Table 2 ▶ for details).
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fig4: Unit-cell contents shown in projection down the a axis for (2). The N—H⋯O and C—H⋯O hydrogen bonds are shown as blue and green dashed lines, respectively (see Table 2 ▶ for details).

Mentions: In (2), the di-cation is linked to two anions via strong N—H⋯O hydrogen bonds (Fig. 4 ▶ and Table 2 ▶). Globally, the three ion aggregates assemble into layers in the ab plane that stack along the c axis. A large number of C—H⋯O inter­actions occur, remarkably featuring a narrow range of H⋯O separations, i.e. 2.41–2.42 Å (Table 2 ▶). All inter­actions involve methyl­ene-H atoms as donors. The carboxyl­ate-O2 and O4 atoms and all nitro but O3 atoms are acceptors; both methyl­ene-H atoms of methyl­ene-C17 and C20 participate in C—H⋯O inter­actions. The result of these inter­actions is the formation of a three-dimensional architecture (Fig. 4 ▶). Additional stability to the supra­molecular assembly is afforded by π—π inter­actions between inversion-related rings, i.e. inter-centroid distances = 3.5644 (16) Å for inter­actions between the C2–C8 rings (symmetry code: −x + 1, −y + 2, −z + 2) and 3.6527 (16) Å between C9–C14 rings (symmetry code: −x + 2, −y + 1, −z). An alternate description of the global crystal packing is based on alternating of layers of cations and layers of anions along the c axis (Fig. 5 ▶).


Crystal structures of 1,4-di-aza-bicyclo-[2.2.2]octan-1-ium 4-nitro-benzoate dihydrate and 1,4-di-aza-bicyclo-[2.2.2]octane-1,4-diium bis-(4-nitro-benzoate): the influence of solvent upon the stoichiometry of the formed salt.

Akhmad Aznan AM, Abdullah Z, Tiekink ER - Acta Crystallogr Sect E Struct Rep Online (2014)

Unit-cell contents shown in projection down the a axis for (2). The N—H⋯O and C—H⋯O hydrogen bonds are shown as blue and green dashed lines, respectively (see Table 2 ▶ for details).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4120614&req=5

fig4: Unit-cell contents shown in projection down the a axis for (2). The N—H⋯O and C—H⋯O hydrogen bonds are shown as blue and green dashed lines, respectively (see Table 2 ▶ for details).
Mentions: In (2), the di-cation is linked to two anions via strong N—H⋯O hydrogen bonds (Fig. 4 ▶ and Table 2 ▶). Globally, the three ion aggregates assemble into layers in the ab plane that stack along the c axis. A large number of C—H⋯O inter­actions occur, remarkably featuring a narrow range of H⋯O separations, i.e. 2.41–2.42 Å (Table 2 ▶). All inter­actions involve methyl­ene-H atoms as donors. The carboxyl­ate-O2 and O4 atoms and all nitro but O3 atoms are acceptors; both methyl­ene-H atoms of methyl­ene-C17 and C20 participate in C—H⋯O inter­actions. The result of these inter­actions is the formation of a three-dimensional architecture (Fig. 4 ▶). Additional stability to the supra­molecular assembly is afforded by π—π inter­actions between inversion-related rings, i.e. inter-centroid distances = 3.5644 (16) Å for inter­actions between the C2–C8 rings (symmetry code: −x + 1, −y + 2, −z + 2) and 3.6527 (16) Å between C9–C14 rings (symmetry code: −x + 2, −y + 1, −z). An alternate description of the global crystal packing is based on alternating of layers of cations and layers of anions along the c axis (Fig. 5 ▶).

Bottom Line: The global crystal structure comprises alternating layers of water mol-ecules and ion pairs stacked along the c axis.In the crystal of (2), the three-ion aggregates are assembled into a three-dimensional architecture by a large number of methyl-ene-carboxyl-ate/nitro C-H⋯O inter-actions as well as π-π contacts between inversion-related benzene rings [inter-centroid distances = 3.5644 (16) and 3.6527 (16) Å].The cations and anions assemble into alternating layers along the c axis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.

ABSTRACT
The 1:1 co-crystallization of 1,4-di-aza-bicyclo-[2.2.2]octane (DABCO) with 4-nitro-benzoic acid in ethanol-water (3/1) gave the salt dihydrate C6H13N2 (+)·C7H4NO4 (-)·2H2O, (1), whereas from methanol, the salt C6H14N2 (2+)·2C7H4NO4 (-), (2), was isolated. In (1), the cation and anion are linked by a strong N-H⋯O hydrogen bond, and the carboxyl-ate anion is close to planar [dihedral angle between terminal residues = 6.83 (9)°]. In (2), a three-ion aggregate is assembled by two N-H⋯O hydrogen bonds, and the carboxyl-ate anions are again close to planar [dihedral angles between terminal residues = 1.7 (3) and 5.9 (3)°]. Through the inter-vention of solvent water mol-ecules, which self-assemble into helical supra-molecular chains along the b axis, the three-dimensional architecture in (1) is stabilized by water-DABCO O-H⋯N and water-carboxyl-ate O-H⋯O hydrogen bonds, with additional stability afforded by C-H⋯O inter-actions. The global crystal structure comprises alternating layers of water mol-ecules and ion pairs stacked along the c axis. In the crystal of (2), the three-ion aggregates are assembled into a three-dimensional architecture by a large number of methyl-ene-carboxyl-ate/nitro C-H⋯O inter-actions as well as π-π contacts between inversion-related benzene rings [inter-centroid distances = 3.5644 (16) and 3.6527 (16) Å]. The cations and anions assemble into alternating layers along the c axis.

No MeSH data available.


Related in: MedlinePlus