1,10-Phenanthrolin-1-ium 2-carb­oxy-4,5-dichloro­benzoate

Graham Smith; Urs D Wermuth; Jonathan M White

doi:10.1107/S1600536809034448

. 2009 Sep 5;65(Pt 10):o2333. doi: 10.1107/S1600536809034448

1,10-Phenanthrolin-1-ium 2-carboxy-4,5-dichlorobenzoate

Graham Smith ^a,^*, Urs D Wermuth ^a, Jonathan M White ^b

PMCID: PMC2970357 PMID: 21577804

Abstract

In the structure of the 1:1 proton-transfer compound of 1,10-phenanthroline with 4,5-dichlorophthalic acid, C₁₂H₉N₂ ⁺·C₈H₃Cl₂O₄ ⁻, determined at 130 K, the 1,10-phenanthrolinium cation and the hydrogen 4,5-dichlorophthalate anion associate through a single N—H⋯O_carboxyl hydrogen bond giving discrete units which have no extension except through a number of weak cation C—H⋯O_anion associations and weak cation–anion aromatic ring π–π interactions [minimum centroid–centroid separation = 3.6815 (12) Å]. The anions are essentially planar "[maximum deviation 0.214 (1) Å (a carboxyl O)] with the syn-related H atom of the carboxyl group, forming a short intramolecular O—H⋯O_carboxyl hydrogen bond.

Related literature

For the structures of other hydrogen 4,5-dichlorophthalate salts, see: Mallinson et al. (2003 ▶); Bozkurt et al. (2006 ▶); Smith et al. (2007 ▶, 2008a ▶,b ▶, 2009a ▶,b ▶). For hydrogen-bond motifs, see: Etter et al. (1990 ▶).

Experimental

Crystal data

C₁₂H₉N₂ ⁺·C₈H₃Cl₂O₄ ⁻
M _r = 415.22
Monoclinic,
a = 6.4598 (11) Å
b = 7.3696 (12) Å
c = 18.302 (3) Å
β = 94.978 (3)°
V = 868.0 (2) Å³
Z = 2
Mo Kα radiation
μ = 0.41 mm⁻¹
T = 130 K
0.55 × 0.45 × 0.05 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.81, T _max = 0.98
5464 measured reflections
3734 independent reflections
3629 reflections with I > 2σ(I)
R _int = 0.017

Refinement

R[F ² > 2σ(F ²)] = 0.032
wR(F ²) = 0.085
S = 1.04
3734 reflections
261 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.19 e Å⁻³
Absolute structure: Flack (1983 ▶), 1564 Friedel pairs
Flack parameter: 0.00 (4)

Data collection: SMART (Bruker, 2000 ▶); cell refinement: SAINT (Bruker, 1999 ▶); 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, 2009 ▶); software used to prepare material for publication: PLATON.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809034448/fl2261sup1.cif

e-65-o2333-sup1.cif^{(21.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809034448/fl2261Isup2.hkl

e-65-o2333-Isup2.hkl^{(179.3KB, 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
N1A—H1A⋯O22	0.90 (2)	1.83 (2)	2.6926 (19)	158 (2)
N1A—H1A⋯N10A	0.90 (2)	2.38 (2)	2.749 (2)	104.3 (15)
O12—H12⋯O21	0.98 (3)	1.43 (3)	2.4054 (19)	179 (4)
C2A—H2A⋯O21	0.93	2.52	3.279 (2)	140
C3—H3⋯O22	0.93	2.26	2.647 (2)	104
C3A—H3A⋯O11ⁱ	0.93	2.44	3.355 (2)	168
C4A—H4A⋯O21ⁱⁱ	0.93	2.49	3.252 (2)	139
C6—H6⋯O11	0.93	2.29	2.668 (2)	103
C6A—H6A⋯O11ⁱⁱⁱ	0.93	2.59	3.270 (2)	130

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

The authors acknowledge financial support from the School of Physical and Chemical Sciences, Queensland University of Technology, and the School of Chemistry, University of Melbourne.

supplementary crystallographic information

Comment

The 1:1 proton-transfer compounds of 4,5-dichlorophthalic acid (DCPA) with the aromatic nitrogen Lewis bases commonly have low-dimensional hydrogen-bonded structures (Smith et al., 2007, 2008a, 2008b, 2009a, 2009b; Bozkurt et al., 2006; Mallinson et al., 2003). In the two-dimensional examples the DCPA anions assume non-planar conformations and form into sheet substructures which in the case of the compounds with the meta- and para-aminobenzoic acids (Smith et al., 2008b) are extended into three-dimensional frameworks through peripheral cyclic head-to-head carboxylic acid hydrogen-bonding associations. However, with the majority of the structures, e.g. the brucinium salt (Smith et al., 2007), the DCPA anions are essentially planar with short intramolecular carboxylic acid O–H···O_carboxyl hydrogen bonds. These features were therefore expected and found in the 1:1 proton-transfer compound of DCPA with 1,10-phenanthroline, (I), reported here.

In (I), a single N⁺–H···O_carboxyl hydrogen bond links the phenanthroline cation and the DCPA anion (Fig. 1). A weak aromatic ring C–H···O_carboxyl interaction (Table 1) completes an asymmetric R²₂(7) cyclic association (Etter et al., 1990). Three additional anion C–H···O interactions represent the only structure extensions present. Some overlap is present between the anion aromatic ring (C1–C6) and one six-membered ring of the cation (N10A, C9A, C8A, C7A, C6A, C14A) [minimum ring centroid separation, 3.6815 (12) Å] (Fig. 2), giving weak π–π stacking interactions (Fig. 3). The DCPA anion is essentially planar [torsion angles C2–C1–C11–O11, -168.30 (16)°: C1–C2–C21–O22, -179.53 (16)°], and exhibits a short intramolecular O–H···O_carboxyl hydrogen bond [2.4054 (19) Å]. Associated with this bond is a significant distortion of the exo-C1 and C2 bond angles [C1–C2–C21, 128.55 (15) ° and C2–C1–C11, 129.18 (16) °]. This and a lengthening of the C1–C11 and C2–C21 bonds [1.538 (3) and 1.536 (3) Å] is common to the planar DCPA anions in the series of 1:1 proton-transfer compounds [angle range: 127.88 (16)° in the nicotinamide salt (Smith et al., 2009a) to 129.27 (14)° in the 8-aminoquinoline salt (Smith et al., 2008a); bond length range: 1.523 (3)–1.535 (3) Å, both in the brucinium salt (Smith et al., 2007).

Experimental

The title compound (I) was synthesized by heating 1 mmol quantities of 1,10-phenanthroline and 4,5-dichlorophthalic acid in 50 ml of 95% ethanol for 10 min under reflux. After concentration to ca. 30 ml, partial room-temperature evaporation of the hot-filtered solution gave colourless plates (m.p. 464–465 K) suitable for data collection.