A co-crystal of 1,10-phenanthroline with boric acid: a novel aza-aromatic complex

Arsalan Mirjafari; Lam Pham; Philip J Smith; Richard E Sykora; James H Davis, Jr

doi:10.1107/S1600536813015134

. 2013 Jun 12;69(Pt 7):o1067–o1068. doi: 10.1107/S1600536813015134

A co-crystal of 1,10-phenanthroline with boric acid: a novel aza-aromatic complex

Arsalan Mirjafari ^a, Lam Pham ^b, Philip J Smith ^b, Richard E Sykora ^b, James H Davis Jr ^b,^*

PMCID: PMC3952236 PMID: 24627684

Abstract

The title compound, C₁₂H₈N₂·2B(OH)₃, is best described as a host–guest complex in which the B(OH)₃ molecules form a hydrogen-bonded cyclic network of layers parallel to the ab plane into which the 1,10-phenanthroline molecules are bound. An extensive network of hydrogen bonds are responsible for the crystal stability. No π-stacking interactions occur between the 1,10-phenanthroline molecules.

Related literature

For the design and synthesis of novel systems of non-covalent hosts involving hydrogen bonds, see: Pedireddi et al. (1997 ▶). In the field of supermolecular synthesis, recognition between the complementary functional groups is a main factor for the evaluation of influence of noncovalent interactions in the formation of specific architecture, see: Lehn (1990 ▶). The ability of the –B(OH)₂ functionality to form a variety of hydrogen bonds through different conformations makes it a very suitable moiety for the synthesis of novel molecular complexes, see: Lee et al. (2005 ▶). It is known to have an affinity for pyridyl N atoms, often forming O—H⋯N hydrogen bonds, as observed in some crystals of boronic acids with aza compounds (Talwelkar & Pedireddi, 2010 ▶). Non-covalent hosts are generally designed and synthesized by employing appropriate functional groups at required symmetry positions to form a cyclic network through the hydrogen bonds, see: Pedireddi (2001 ▶). This effect has been observed in simple molecular adducts such as 1,10-phenanthroline and water (Tian et al., 1995 ▶). graphic file with name e-69-o1067-scheme1.jpg

Experimental

Crystal data

C₁₂H₈N₂·2BH₃O₃
M _r = 303.87
Triclinic,
a = 7.1390 (13) Å
b = 9.6189 (13) Å
c = 10.4756 (15) Å
α = 93.767 (11)°
β = 101.546 (14)°
γ = 90.644 (13)°
V = 703.05 (19) Å³
Z = 2
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 295 K
0.35 × 0.16 × 0.09 mm

Data collection

Oxford Diffraction Xcalibur Eos diffractometer
Absorption correction: multi-scan [CrysAlis PRO (Oxford Diffraction, 2011 ▶) based on Clark & Reid (1995 ▶)] T _min = 0.956, T _max = 1.000
10473 measured reflections
2580 independent reflections
1972 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.036
wR(F ²) = 0.096
S = 1.02
2580 reflections
199 parameters
H-atom parameters constrained
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.13 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2011 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶) and OLEX2 (Dolomanov et al., 2009 ▶); software used to prepare material for publication: publCIF (Westrip, 2010) ▶.

Supplementary Material

Crystal structure: contains datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S1600536813015134/ez2287sup1.cif

e-69-o1067-sup1.cif^{(16.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813015134/ez2287Isup2.hkl

e-69-o1067-Isup2.hkl^{(126.7KB, hkl)}

Click here for additional data file.^{(5.4KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536813015134/ez2287Isup3.cml

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
O1—H1⋯N2	0.85	1.90	2.7360 (16)	169
O2—H2⋯N1	0.85	1.88	2.7132 (17)	167
O3—H3⋯O1ⁱ	0.85	1.86	2.7076 (15)	177
O4—H4⋯O3ⁱ	0.85	1.89	2.7286 (16)	16
O5—H5⋯O4ⁱⁱ	0.85	1.89	2.7355 (18)	179
O6—H6⋯O2ⁱⁱⁱ	0.85	1.95	2.7946 (17)	172

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

Acknowledgments

The authors acknowledge the National Science Foundation for their generous support (NSF-CAREER grant to RES, CHE-0846680).

supplementary crystallographic information

Comment

The design and synthesis of novel systems of noncovalent hosts involving hydrogen bonds is a vast research area in both molecular and supermolecular chemistry, see Pedireddi et al. (1997). In the field of supermolecular synthesis, recognition between the complementary functional groups is a main factor for the evaluation of influence of noncovalent interaction in the formation of specific architecture, see: Lehn (1990). In recent times, boric acid derivatives have been well considered to be potential co-crystal formers. In fact, the ability of –B(OH)₂ functionality to form a variety of hydrogen bonds through different conformations makes it a very suitable moiety for the synthesis of novel molecular complexes, see Lee et al. (2005). The –B(OH)₂ moiety is known to have an affinity for pyridyl N-atoms, often forming O—H···N hydrogen bonds, as observed in some crystals of boronic acids with aza compounds,see Talwelkar & Pedireddi (2010).

Non-covalent hosts are generally designed and synthesized by employing appropriate functional groups at required symmetry positions to form a cyclic network through the hydrogen bonds, see Pedireddi (2001). This effect has been observed vividly in simple molecular adduct such as 1,10-phenanthroline and water, see Tian et al. (1995). In this complex, a water molecule interacts with a molecule of 1,10-phenanthroline through O–H···N hydrogen bonds and an unique aza-aromatic complex is formed. In the latter, 1,10-phenanthroline could be considered as a host. Herein, we report the crystal structure of boric acid with 1,10-phenanthroline as an aza-donor compound.

As seen in Figure 1, the phen molecule forms a H-bonded adduct via two B–O–H···N interacts from one of the included B(OH)₃ moieties. A strong network of hydrogen bonds among the B(OH)₃ units forms a layered structure with alternating B(OH)₃ and phen layers that reside in the ab planes (Figure 2). The B(OH)₃ layers alone can be described as a cyclic network formed by hydrogen bonding interactions as can be seen in Figure 3. There are not any significant π-stacking interactions between the phen molecules.

Experimental

(CH₃)₃NBH₃ (0.73 g, 10 mmol) and iodine (2.54 g, 5 mmol) were dissolved in toluene (4 ml) and stirred for 30 min. A solution of 1,10-phenanthroline (1.98 g, 10 mmol) in toluene (4 ml) was added, and the mixture refluxed overnight. The solution was cooled to room temperature, during which process orange-brown crystals were formed. The product was recrystallized twice from CH₃CN to obtain analytically pure, red-brown crystalline product.

¹H NMR (DMSO-d₆, 300 MHz): δ_H 9.22 (dd, J = 2.8, 1.6 Hz, 2H), 8.67 (dd, J = 6.3, 1.6 Hz, 2H), 8.14 (s, 2H), 7.93 (q, J = 4.4 Hz, 2H), 6.62 (br, 2H); ¹³C NMR (DMSO-d₆, 100 MHz): δ_C 151.67, 146.27, 139.09, 130.58, 128.77, 125.66.