Morpholinium 2,4,6-trinitro­phenolate

Nagarajan Vembu; Frank R Fronczek

doi:10.1107/S1600536808042657

. 2008 Dec 20;65(Pt 1):o156–o157. doi: 10.1107/S1600536808042657

Morpholinium 2,4,6-trinitrophenolate

Nagarajan Vembu ^a,^*, Frank R Fronczek ^b

PMCID: PMC2968070 PMID: 21581614

Abstract

There are two independent formula units in the asymmetric unit of the title compound, C₄H₁₀NO⁺·C₆H₂N₃O₇ ⁻. The morpholinium cations in both molecules are puckered and adopt a chair conformation. Intermolecular N—H⋯O and C—H⋯O interactions generate rings of motifs R ₂ ¹(5) and R ₁ ²(6). The supramolecular aggregation is completed by the presence of two co-operative hydrogen-bonded networks of further N—H⋯O interactions, which generate an infinite one-dimensional chain along the base vector [100]. Two C—H⋯π interactions are also seen.

Related literature

For a detailed account of the design of organic polar crystals, see: Pecaut & Bagieu-Beucher (1993 ▶). For hydrogen bonding in nitrophenol complexes, see: In et al. (1997 ▶); Zadrenko et al. (1997 ▶); Mizutani et al. (1998 ▶). For the supramolecular architecture of molecular complexes of trinitrophenols, see: Botoshansky et al. (1994 ▶); Vembu et al. (2003 ▶). For puckering paramaters, see: Cremer & Pople (1975 ▶). For hydrogen-bonding criteria, see: Desiraju & Steiner (1999 ▶); Desiraju (1989 ▶); Jeffrey (1997 ▶). For graph-set notation, see: Bernstein et al. (1995 ▶); Etter (1990 ▶).

Experimental

Crystal data

C₄H₁₀NO⁺·C₆H₂N₃O₇ ⁻
M _r = 316.24
Triclinic,
a = 8.3179 (5) Å
b = 9.5733 (5) Å
c = 16.8451 (10) Å
α = 91.292 (4)°
β = 98.604 (4)°
γ = 107.589 (4)°
V = 1261.00 (13) Å³
Z = 4
Cu Kα radiation
μ = 1.28 mm⁻¹
T = 90.0 (5) K
0.25 × 0.22 × 0.13 mm

Data collection

Bruker Kappa APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2006 ▶) T _min = 0.745, T _max = 0.851
14930 measured reflections
4520 independent reflections
4172 reflections with I > 2σ(I)
R _int = 0.025

Refinement

R[F ² > 2σ(F ²)] = 0.029
wR(F ²) = 0.075
S = 1.04
4520 reflections
494 parameters
All H-atom parameters refined
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: APEX2 and SAINT (Bruker, 2006 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2003 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808042657/sj2568sup1.cif

e-65-0o156-sup1.cif^{(27.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808042657/sj2568Isup2.hkl

e-65-0o156-Isup2.hkl^{(221.4KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N20A—H20A⋯O17B	0.905 (18)	1.938 (18)	2.8011 (14)	158.9 (15)
C21A—H21B⋯O13B	0.976 (17)	2.485 (16)	3.1491 (16)	125.1 (12)
C22B—H22C⋯O12B	0.985 (17)	2.531 (17)	3.3427 (16)	139.6 (12)
N20A—H20B⋯O7Bⁱ	0.930 (19)	1.885 (19)	2.6838 (14)	142.6 (15)
N20A—H20B⋯O15Bⁱ	0.930 (19)	2.225 (18)	2.9229 (15)	131.2 (14)
C18B—H18C⋯O9Bⁱ	0.954 (17)	2.559 (16)	3.3078 (17)	135.5 (12)
N20B—H20C⋯O7Aⁱⁱ	0.888 (18)	1.930 (18)	2.6911 (14)	142.8 (15)
N20B—H20C⋯O9Aⁱⁱ	0.888 (18)	2.255 (18)	2.9248 (15)	132.1 (14)
N20B—H20D⋯O12Aⁱⁱⁱ	0.930 (19)	2.528 (17)	2.8693 (14)	102.0 (12)
C18B—H18D⋯O10Bⁱⁱⁱ	0.967 (17)	2.571 (17)	3.1533 (16)	118.8 (12)
C21B—H21C⋯O12Aⁱⁱⁱ	0.956 (16)	2.514 (16)	3.1210 (16)	121.4 (12)
N20B—H20D⋯O17A^iv	0.930 (19)	1.946 (19)	2.8182 (14)	155.4 (15)
C3B—H3B⋯O16B^v	0.958 (17)	2.495 (18)	3.4394 (17)	168.5 (13)
C5A—H5A⋯O10A^v	0.968 (17)	2.492 (17)	3.4436 (16)	167.7 (13)
C18A—H18A⋯O15A^vi	0.956 (17)	2.474 (17)	3.2628 (17)	139.7 (13)
C21B—H21D⋯O15A^vi	0.965 (17)	2.461 (17)	3.3679 (16)	156.6 (12)
C21A—H21A⋯O9B^vii	0.972 (16)	2.499 (16)	3.4139 (16)	156.8 (12)
C21A—H21B⋯O16A^viii	0.976 (17)	2.473 (16)	3.1274 (16)	124.2 (12)
C22A—H22B⋯O13A^ix	0.952 (17)	2.595 (17)	3.3916 (16)	141.3 (13)
C18A—H18A⋯Cg4^ix	0.958 (18)	2.906	3.718	140.37
C22B—H22C⋯Cg3^x	0.991 (18)	3.152	3.896	133.06

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) ; (viii) ; (ix) ; (x) . Cg3 and Cg4 are the centroids of the C1A–C6A and C1B–C6B rings, respectively.

Acknowledgments

NV thanks the University Grants Commission (UGC), Government of India, for a minor research project grant [MRP-2219/06(UGC-SERO)].

supplementary crystallographic information

Comment

The design of organic polar crystals for quadratic non-linear optical applications is supported by the observation that the organic molecules containing π-electron systems asymmetrized by electron donor and acceptor groups are highly polarizable entities in which problems of transparency and crystal growth may arise from their molecular crystal packing (Pecaut & Bagieu-Beucher, 1993). It is known that nitrophenols act not only as π-acceptor to form various π-stacking complexes with other aromatic molecules, but also as an acidic ligand to form salts through specific electrostatic or H-bonding interactions (In et al., 1997). The bonding of electron-donor acceptor complexes strongly depends on the nature of the partners. The linkage could involve not only electrostatic interactions, but also the formation of molecular complexes (Zadrenko et al., 1997). It has been reported that proton transferred thermochromic complexes were formed between phenols and amines in apolar solvents at low temperature if an appropriate H-bonding network between phenols and amines were present to stabilize it (Mizutani et al., 1998). Pyridinium picrate has been reported in two crystalline phases and it appears in both phases as an internally linked H-bonded ion pair. These two phases are termed as molecular crystals rather than salts based on their structural arrangements (Botoshansky et al., 1994). A similar structural arrangement has also been reported for 4-dimethylaminopyridinium picrate (Vembu et al., 2003). In continuation of our investigations on the supramolecular architecture of picrates, the X-ray diffraction study on the title compound is carried out.

The asymmetric unit of (I) contains two morpholinium cations and and two 2,4,6-trinitrophenolate anions. (Fig.1). The morpholinium cation is puckered in both the molecules with the Cremer and Pople puckering parameters Q, θ and φ (Cremer & Pople, 1975) in the two molecules being, 0.590 (1)Å & 0.588 (1) Å, 179.7 (2)° & 0.7 (1)°, 285 (13)° & 63 (11)°, respectively. The morpolinium cation in both the molecules adopt a chair conformation as discerned from the respective torsion angles.

The crystal structure of (I) is stabilized by N—H···O and C—H···O interactions. The range of H···O distances (Table 1) found in (I) agrees with those found for N—H···O (Jeffrey, 1997) and C—H···O hydrogen bonds (Desiraju & Steiner, 1999). The N20A—H20B···O7Bⁱ and N20A—H20B···O15Bⁱ interactions form a pair of bifurcated donor bonds that form a motif of graph set (Bernstein et al., 1995; Etter, 1990) R₁²(6). Another pair of bifurcated donor bonds consists of the N20B—H20C···O7Aⁱⁱ and N20B—H20C···O9Aⁱⁱ interactions that also generate a R₁²(6) motif. The N20B—H20D···O12Aⁱⁱⁱ and C21B—H21C···O12Aⁱⁱⁱ interactions constitute a pair of bifurcated acceptor bonds that generate a ring motif of graph set R₂¹(5). The N20A—H20A···O17B, N20A—H20B···O7Bⁱ and N20A—H20B···O15Bⁱ interactions generate a cooperative H-bonded network. Another cooperative H-bonded network is formed by the interactions, N20B—H20C···O7Aⁱⁱ, N20B—H20C···O9Aⁱⁱ, N20B—H20D···O12Aⁱⁱⁱ and N20B—H20D···O17A^iv. These two networks generate an infinite one dimensional chain along the base vector [100]. The C18A—H18A···Cg4^viii interaction (Table 2) is classified as an offset face to face interaction with γ = 4.45° and perpendicular distance 2.897Å whereas the C22B—H22C···Cg3^ix is termed as edge to face interaction with γ = 20.34° with a perpendicular distance 2.956Å where Cg4 is the centroid of the ring formed by the atoms C1B—C6B and Cg3 is the centroid of the ring formed by the atoms C1A—C6A. There are two face to face π···π interactions in the title compound with coordinates Cg3···Cg3 (2 - x, 1 - y, -z) with α = 0.00°, β & γ = 19.38°, with perpendicular distance 3.449Å and Cg4···Cg4 (2 - x, 1 - y, 1 - z) with α = 0.02°, β & γ = 18.71°, and perpendicular distance 3.461 Å.

The interplay of strong N—H···O and weak C—H···O, C—H···π and π···π interactions with different strengths, directional preferences and distances presents a complex mosaic of interactions. The three dimensional arrangement of 2,4,6-trinitrophenolate and morpholinium moieties in the unit cell, shows that the title compound is an internally linked hydrogen bonded ion pair and hence can be regarded as a molecular crystal rather than a salt.

Experimental

2,4,6-Trinitrophenol (5.2 mmol) dissolved in aqueous ethanol (25 ml) was added dropwise to morpholine (5.7 mmol) in aqueous ethanol (25 ml). The above solution was constantly stirred at room temperature for 2 hrs. The precipitated product was filtered and recrystallized from aqueous ethanol. Yield 75% (3.9 mmol).