Ammonium hydrogen bis­[4-(2-phenyl-2H-tetra­zol-5-yl)benzoate]

Janzen, D.E.; Lange, K.A.; Wollack, J.W.

doi:10.1107/S2414314616015704

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 1| Part 10| October 2016| x161570

https://doi.org/10.1107/S2414314616015704

Open

access

Ammonium hydrogen bis[4-(2-phenyl-2H-tetrazol-5-yl)benzoate]

Daron E. Janzen,^a ^* Kayla A. Lange ^a and James W. Wollack ^a

^aSt. Catherine University, Dept. of Chemistry and Biochemistry, 2004 Randolph Avenue, St. Paul, MN 55105, USA
^*Correspondence e-mail: dejanzen@stkate.edu

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 21 September 2016; accepted 5 October 2016; online 14 October 2016)

The title salt, NH₄⁺·H⁺·2C₁₄H₉N₄O₂⁻, is composed of an ammonium cation with a strong intermolecular negatively charge-assisted hydrogen-bonded acid/conjugate base-pair monoanion. The carboxylic acid H atom is located on an inversion center, while the N atom of the ammonium cation is located on a twofold rotation axis. In the crystal, the N—H bonds of each ammonium cation act as donors with carboxylate O-atom acceptors to form chains along the a-axis direction. The chains are linked by offset π–π interactions [intercentroid distances = 3.588 (2) and 3.686 (2) Å], forming layers parallel to the ab plane.

Keywords: crystal structure; tetrazole; photoclick chemistry; O⋯O symmetric hydrogen bond; ammonium.

CCDC reference: 1508475

Structure description

Tetrazoles are an interesting class of compounds that are utilized in a bioorthogonal reaction called photoclick chemistry (Ramil & Lin, 2014 ). When tetrazoles are irradiated with UV light, a nitrile imine is formed which can subsequently complete a cycloaddition with olefins present in situ (Zheng et al., 2009 ). After cycloaddition, a fluorescent pyrazoline is produced that can be used as a tag to monitor product formation. This technology has been successfully used to impart fluorescent properties onto alkene-containing proteins (Song et al., 2008 ; Lim & Lin, 2011 ). Upon synthesizing 4-(2-phenyl-2H-tetrazol-5-yl)benzoic acid for this purpose, X-ray diffraction quality ammonium salt crystals of the title compound were produced and we report herein on its crystal structure.

The molecular structure of the title compound is illustrated in Fig. 1. The ammonium cation (N5) is located on a twofold rotation axis, and the carboxylic acid H atom (H1A), located on an inversion center, interacts with two inversion-related 4-(2-phenyl-2H-tetrazol-5-yl)benzoate ions (Fig. 1 and Table 1). The conjugate acid/base O1⋯O1(−x + 1, −y − 2, −z + 1) distance of 2.561 (3) Å is short, consistent with a strong negatively charge-assisted hydrogen bond (Gilli et al., 2009 ). The narrow range of bond lengths [1.312 (3)–1.359 (3) Å] in the tetrazole moiety suggests significant conjugation in this ring. The 4-(2-phenyl-2H-tetrazol-5-yl)benzoate moiety is relatively planar. The phenyl (atoms C1–C6) and benzoate rings (atoms C8–C13) are inclined to the plane of the tetrazole ring (atoms N1–N4/C7) by 2.54 (15) and 6.10 (14)°, respectively, and by 3.84 (13)° to each another. The acetate group (C11/C14/O1/O2) is inclined to the benzene ring (C8–C13) to which it is attached by 10.44 (14)°.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1A⋯O1ⁱ	1.28	1.28	2.561 (3)	180
N5—H5A⋯O2ⁱⁱ	0.80 (8)	2.09 (8)	2.815 (4)	151 (7)
N5—H5B⋯O1ⁱⁱⁱ	0.84 (11)	2.15 (10)	2.8513 (18)	140 (9)
Symmetry codes: (i) -x+1, -y-2, -z+1; (ii) $[x+{\script{1\over 2}}, -y-1, z]$ ; (iii) $[-x+{\script{3\over 2}}, y+1, -z+1]$ .

Figure 1
A view of the molecular structure of the title compound, showing the atom labeling. Displacement ellipsoids are drawn at the 50% probability level. The acidic H atom, H1A, is located on in inversion center, and unlabeled atoms of the anion are related to the labelled atoms by the inversion symmetry code (−x + 1, −y − 2, −z + 1).

In the crystal, intermolecular hydrogen bonding is present between the ammonium donor and four O-atom acceptors from two conjugate acid/base pairs. The hydrogen-bonding motif [R₂²(8)] occurs as a chain of rings (joined at N5) along the a-axis direction plane (Table 1 and Fig. 2). This pattern of hydrogen bonding is unique to the small group of existing reported ammonium hydrogen bis(carboxylate) structures, which all exhibit hydrogen bonding of ammonium cations with carboxylate O atoms from four unique conjugate acid/base pairs (Chowdhury & Kariuki, 2006 ; Golic & Lazarini, 1975 ; Ichikawa, 1972 ; Nahringbauer, 1969 ; Perumalla & Sun, 2013 ). Adjacent chains are linked via offset π–π interactions, forming layers parallel to the ab plane; see Fig. 3 [Cg1⋯Cg3ⁱ = 3.588 (2) Å, interplanar distance = 3.480 (1) Å, slippage = 1.121 Å; Cg1⋯Cg2ⁱⁱ = 3.686 (2) Å, interplanar distance = 3.352 (1) Å, slippage = 1.384 Å; Cg1, Cg2, and Cg3 are the centroids of the N1–N4/C7, C1–C6 and C8–C13 rings, respectively; symmetry codes: (i) x, y + 1, z; (ii) x, y − 1, z].

Figure 2
A view of the hydrogen bonding involving the ammonium cation. The hydrogen bonds are shown as dashed lines (see Table 1

) and, for clarity, the C-bound H atoms have been omitted.

Figure 3
A view along the a axis of the crystal packing of the title compound. The hydrogen bonds are shown as dashed lines (see Table 1

) and, for clarity, the C-bound H atoms have been omitted.

Synthesis and crystallization

The title compound was synthesized using procedures adopted from multiple literature reports (Song et al., 2008; Ito et al., 1976 ). To a solution of 4-formylbenzoic acid (0.75 g, 5.0 mmol) in ethanol (50 ml) was added benzenesulfonohydrazide (0.86 g, 25 mmol) and the solution was stirred for 35 min. Water (200 ml) was then added and the beaker containing the reaction was placed in an ice bath to produce a precipitate, which was subsequently filtered off and dissolved in pyridine (30 ml). This was labeled solution A. In another flask aniline (0.47 g, 5.0 mmol) was dissolved in a solution consisting of water (4 ml), ethanol (4 ml), and concentrated HCl (1.3 ml). This solution was placed in an ice bath while a cooled solution of NaNO₂ (0.35 g, 5.0 mmol) in 2 ml water was added dropwise. This was labeled solution B. Solution A was then placed in an ice salt bath while solution B was added dropwise over 10 min under magnetic stirring. This solution was allowed to sit for 20 min, after which time it was extracted with ethyl acetate (3 × 30 ml). Then 3 M HCl (250 ml) was added to the combined organic extracts and the mixture was stirred for 15 min. The organic layer was then collected, concentrated, and recrystallized from hot ethyl acetate to produce 0.235 g of light-pink crystals of 4-(2-phenyl-2H-tetrazol-5-yl)benzoic acid (17.7% yield). ¹H NMR (400 MHz, DMSO-d₆): δ 13.31 (br s, 1H), 8.27 (d, J = 8.7 Hz, 2H), 8.14 (d, J = 7.8, 2H), 8.12 (d, J = 8.3 Hz, 2H), 7.68 (dd, J = 7.8, 8.7 Hz, 2H), 7.61 (t, J = 7.3 Hz, 1H); ¹³C NMR (100 MHz, DMSO-d₆): δ 166.6, 163.6, 136.0, 132.6 130.3, 130.2, 130.1, 126.7, 119.1.

Crystals of the title compound were prepared by dissolving 4-(2-phenyl-2H-tetrazol-5-yl)benzoic acid (30 mg) in 6 ml of a 2:1 solution of methanol–H₂O. This gave a cloudy solution which became clear on the addition of 6 drops of 6 M NH₄OH. The solution was allowed to sit in an open vial at room temperature, and yielded colourless prismatic crystals of the title compound after ca 10 d.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	NH₄⁺·H⁺·2C₁₄H₉N₄O₂⁻
M_r	549.55
Crystal system, space group	Monoclinic, I2/a
Temperature (K)	173
a, b, c (Å)	12.350 (3), 4.8107 (13), 42.812 (11)
β (°)	97.569 (9)
V (Å³)	2521.4 (12)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.10
Crystal size (mm)	0.43 × 0.43 × 0.08

Data collection
Diffractometer	Rigaku XtaLAB mini
Absorption correction	Multi-scan (REQAB; Rigaku, 1998 )
T_min, T_max	0.679, 0.992
No. of measured, independent and observed [F² > 2.0σ(F²)] reflections	4744, 2206, 1788
R_int	0.031
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.060, 0.128, 1.19
No. of reflections	2206
No. of parameters	195
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.23, −0.21
Computer programs: CrystalClear-SM Expert (Rigaku, 2011 ), SIR2004 (Burla et al., 2005 ), SHELXL97 (Sheldrick, 2008 ), Mercury (Macrae et al., 2008 ) and CrystalStructure (Rigaku, 2014 ).

Structural data

CCDC reference: 1508475

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S2414314616015704/su4081sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314616015704/su4081Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314616015704/su4081Isup3.cml

checkCIF report

Computing details top

Data collection: CrystalClear-SM Expert (Rigaku, 2011); cell refinement: CrystalClear-SM Expert (Rigaku, 2011); data reduction: CrystalClear-SM Expert (Rigaku, 2011); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: CrystalStructure (Rigaku, 2014).

Ammonium hydrogen bis[4-(2-phenyl-2H-tetrazol-5-yl)benzoate] top

Crystal data top

NH₄⁺·H⁺·2C₁₄H₉N₄O₂⁻	F(000) = 1144.00
M_r = 549.55	D_x = 1.448 Mg m⁻³
Monoclinic, I2/a	Mo Kα radiation, λ = 0.71075 Å
a = 12.350 (3) Å	Cell parameters from 4069 reflections
b = 4.8107 (13) Å	θ = 3.3–25.1°
c = 42.812 (11) Å	µ = 0.10 mm⁻¹
β = 97.569 (9)°	T = 173 K
V = 2521.4 (12) Å³	Prism, colourless
Z = 4	0.43 × 0.43 × 0.08 mm

Data collection top

Rigaku XtaLAB mini diffractometer	2206 independent reflections
Radiation source: sealed X-ray tube	1788 reflections with F² > 2.0σ(F²)
Detector resolution: 6.849 pixels mm^-1	R_int = 0.031
ω scans	θ_max = 25.0°, θ_min = 3.3°
Absorption correction: multi-scan (REQAB; Rigaku, 1998)	h = −14→12
T_min = 0.679, T_max = 0.992	k = −5→5
4744 measured reflections	l = −50→50

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.060	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.128	H atoms treated by a mixture of independent and constrained refinement
S = 1.19	w = 1/[σ²(F_o²) + (0.0357P)² + 4.8932P] where P = (F_o² + 2F_c²)/3
2206 reflections	(Δ/σ)_max < 0.001
195 parameters	Δρ_max = 0.23 e Å⁻³
0 restraints	Δρ_min = −0.21 e Å⁻³
Primary atom site location: structure-invariant direct methods

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F². R-factor (gt) are based on F. The threshold expression of F² > 2.0 sigma(F²) is used only for calculating R-factor (gt).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O1	0.52029 (14)	−0.8059 (4)	0.48115 (4)	0.0259 (4)
O2	0.34227 (14)	−0.6986 (4)	0.47209 (5)	0.0359 (5)
N1	0.45919 (17)	0.2934 (5)	0.35894 (5)	0.0260 (5)
N2	0.51882 (16)	0.4507 (5)	0.34221 (5)	0.0248 (5)
N3	0.62631 (17)	0.4060 (5)	0.34874 (6)	0.0326 (6)
N4	0.63802 (18)	0.2133 (5)	0.37061 (6)	0.0321 (6)
N5	0.7500	0.1560 (9)	0.5000	0.0551 (14)
C1	0.4723 (2)	0.6455 (5)	0.31930 (6)	0.0242 (6)
C2	0.3595 (2)	0.6681 (6)	0.31350 (7)	0.0318 (7)
H2	0.3137	0.5576	0.3247	0.038*
C3	0.3158 (2)	0.8570 (6)	0.29087 (7)	0.0366 (7)
H3	0.2387	0.8747	0.2863	0.044*
C4	0.3818 (2)	1.0198 (6)	0.27481 (7)	0.0358 (7)
H4	0.3503	1.1480	0.2593	0.043*
C5	0.4942 (2)	0.9957 (6)	0.28133 (7)	0.0354 (7)
H5	0.5399	1.1084	0.2704	0.043*
C6	0.5402 (2)	0.8083 (6)	0.30370 (6)	0.0304 (7)
H6	0.6173	0.7917	0.3083	0.037*
C7	0.5358 (2)	0.1465 (6)	0.37659 (6)	0.0238 (6)
C8	0.5118 (2)	−0.0604 (6)	0.39962 (6)	0.0245 (6)
C9	0.4036 (2)	−0.1329 (6)	0.40206 (6)	0.0265 (6)
H9	0.3455	−0.0479	0.3887	0.032*
C10	0.3813 (2)	−0.3281 (6)	0.42394 (6)	0.0254 (6)
H10	0.3076	−0.3769	0.4254	0.030*
C11	0.4652 (2)	−0.4553 (6)	0.44397 (6)	0.0236 (6)
C12	0.5730 (2)	−0.3826 (6)	0.44126 (6)	0.0277 (6)
H12	0.6310	−0.4687	0.4546	0.033*
C13	0.5963 (2)	−0.1879 (6)	0.41957 (6)	0.0279 (6)
H13	0.6701	−0.1398	0.4181	0.034*
C14	0.4385 (2)	−0.6670 (6)	0.46713 (6)	0.0249 (6)
H1A	0.5000	−1.0000	0.5000	0.11 (2)*
H5A	0.770 (8)	0.061 (16)	0.4864 (18)	0.19 (4)*
H5B	0.806 (8)	0.25 (2)	0.507 (3)	0.31 (7)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0212 (9)	0.0254 (10)	0.0312 (10)	0.0015 (8)	0.0033 (8)	0.0051 (8)
O2	0.0192 (10)	0.0465 (13)	0.0433 (12)	0.0006 (9)	0.0088 (8)	0.0150 (10)
N1	0.0245 (12)	0.0269 (12)	0.0278 (12)	−0.0017 (10)	0.0084 (10)	0.0009 (10)
N2	0.0194 (11)	0.0284 (13)	0.0277 (12)	−0.0011 (10)	0.0067 (9)	0.0024 (10)
N3	0.0188 (11)	0.0408 (15)	0.0387 (14)	0.0015 (11)	0.0062 (10)	0.0105 (12)
N4	0.0219 (12)	0.0390 (15)	0.0361 (14)	0.0018 (10)	0.0060 (10)	0.0125 (12)
N5	0.0184 (19)	0.022 (2)	0.126 (5)	0.000	0.014 (2)	0.000
C1	0.0252 (13)	0.0231 (14)	0.0244 (13)	0.0010 (11)	0.0036 (11)	−0.0015 (12)
C2	0.0247 (14)	0.0338 (16)	0.0383 (16)	0.0012 (13)	0.0090 (12)	0.0009 (14)
C3	0.0250 (15)	0.0414 (18)	0.0426 (18)	0.0058 (13)	0.0015 (13)	−0.0008 (15)
C4	0.0412 (17)	0.0316 (17)	0.0334 (16)	0.0078 (14)	0.0002 (13)	0.0039 (14)
C5	0.0366 (16)	0.0335 (17)	0.0378 (16)	−0.0003 (14)	0.0107 (13)	0.0049 (14)
C6	0.0255 (14)	0.0355 (16)	0.0309 (15)	0.0001 (13)	0.0058 (12)	0.0035 (14)
C7	0.0207 (13)	0.0265 (15)	0.0243 (13)	0.0016 (11)	0.0033 (11)	−0.0022 (12)
C8	0.0230 (13)	0.0262 (15)	0.0250 (14)	0.0007 (12)	0.0058 (11)	−0.0034 (12)
C9	0.0204 (13)	0.0301 (16)	0.0288 (14)	0.0017 (11)	0.0029 (11)	0.0022 (13)
C10	0.0176 (13)	0.0298 (15)	0.0291 (14)	−0.0001 (11)	0.0047 (11)	0.0010 (13)
C11	0.0217 (13)	0.0242 (14)	0.0260 (14)	0.0001 (11)	0.0067 (11)	−0.0043 (12)
C12	0.0189 (13)	0.0304 (15)	0.0332 (15)	0.0020 (11)	0.0013 (11)	0.0030 (13)
C13	0.0194 (13)	0.0317 (15)	0.0333 (15)	−0.0025 (12)	0.0052 (11)	0.0009 (13)
C14	0.0232 (14)	0.0243 (14)	0.0275 (14)	0.0016 (11)	0.0047 (11)	−0.0019 (12)

Geometric parameters (Å, º) top

O1—C14	1.291 (3)	C4—H4	0.9500
O2—C14	1.244 (3)	C5—C6	1.382 (4)
N1—N2	1.329 (3)	C5—H5	0.9500
N1—C7	1.333 (3)	C6—H6	0.9500
N2—N3	1.337 (3)	C7—C8	1.458 (4)
N2—C1	1.422 (3)	C8—C9	1.399 (3)
N3—N4	1.312 (3)	C8—C13	1.400 (4)
N4—C7	1.359 (3)	C9—C10	1.379 (4)
N5—H5A	0.80 (8)	C9—H9	0.9500
N5—H5B	0.84 (11)	C10—C11	1.396 (4)
C1—C6	1.382 (4)	C10—H10	0.9500
C1—C2	1.387 (4)	C11—C12	1.396 (3)
C2—C3	1.385 (4)	C11—C14	1.489 (4)
C2—H2	0.9500	C12—C13	1.376 (4)
C3—C4	1.378 (4)	C12—H12	0.9500
C3—H3	0.9500	C13—H13	0.9500
C4—C5	1.384 (4)

N2—N1—C7	101.8 (2)	N1—C7—N4	112.0 (2)
N1—N2—N3	113.7 (2)	N1—C7—C8	123.5 (2)
N1—N2—C1	123.0 (2)	N4—C7—C8	124.4 (2)
N3—N2—C1	123.3 (2)	C9—C8—C13	119.2 (2)
N4—N3—N2	106.0 (2)	C9—C8—C7	120.2 (2)
N3—N4—C7	106.5 (2)	C13—C8—C7	120.6 (2)
H5A—N5—H5B	103 (8)	C10—C9—C8	119.9 (2)
C6—C1—C2	121.9 (3)	C10—C9—H9	120.1
C6—C1—N2	119.4 (2)	C8—C9—H9	120.1
C2—C1—N2	118.7 (2)	C9—C10—C11	121.2 (2)
C3—C2—C1	117.8 (3)	C9—C10—H10	119.4
C3—C2—H2	121.1	C11—C10—H10	119.4
C1—C2—H2	121.1	C12—C11—C10	118.5 (2)
C4—C3—C2	121.4 (3)	C12—C11—C14	121.6 (2)
C4—C3—H3	119.3	C10—C11—C14	119.8 (2)
C2—C3—H3	119.3	C13—C12—C11	120.9 (2)
C3—C4—C5	119.7 (3)	C13—C12—H12	119.6
C3—C4—H4	120.2	C11—C12—H12	119.6
C5—C4—H4	120.2	C12—C13—C8	120.3 (2)
C6—C5—C4	120.3 (3)	C12—C13—H13	119.9
C6—C5—H5	119.8	C8—C13—H13	119.9
C4—C5—H5	119.9	O2—C14—O1	124.3 (2)
C5—C6—C1	119.0 (3)	O2—C14—C11	119.9 (2)
C5—C6—H6	120.5	O1—C14—C11	115.8 (2)
C1—C6—H6	120.5

C7—N1—N2—N3	0.2 (3)	N3—N4—C7—C8	−179.8 (3)
C7—N1—N2—C1	179.5 (2)	N1—C7—C8—C9	6.1 (4)
N1—N2—N3—N4	−0.2 (3)	N4—C7—C8—C9	−174.2 (3)
C1—N2—N3—N4	−179.5 (2)	N1—C7—C8—C13	−173.7 (3)
N2—N3—N4—C7	0.1 (3)	N4—C7—C8—C13	6.1 (4)
N1—N2—C1—C6	177.7 (3)	C13—C8—C9—C10	0.0 (4)
N3—N2—C1—C6	−3.1 (4)	C7—C8—C9—C10	−179.8 (3)
N1—N2—C1—C2	−1.7 (4)	C8—C9—C10—C11	0.3 (4)
N3—N2—C1—C2	177.6 (3)	C9—C10—C11—C12	−0.6 (4)
C6—C1—C2—C3	1.3 (4)	C9—C10—C11—C14	−179.5 (2)
N2—C1—C2—C3	−179.4 (3)	C10—C11—C12—C13	0.6 (4)
C1—C2—C3—C4	−0.7 (4)	C14—C11—C12—C13	179.5 (3)
C2—C3—C4—C5	−0.1 (5)	C11—C12—C13—C8	−0.4 (4)
C3—C4—C5—C6	0.4 (5)	C9—C8—C13—C12	0.1 (4)
C4—C5—C6—C1	0.2 (4)	C7—C8—C13—C12	179.9 (3)
C2—C1—C6—C5	−1.1 (4)	C12—C11—C14—O2	169.8 (3)
N2—C1—C6—C5	179.6 (3)	C10—C11—C14—O2	−11.3 (4)
N2—N1—C7—N4	−0.1 (3)	C12—C11—C14—O1	−9.5 (4)
N2—N1—C7—C8	179.7 (2)	C10—C11—C14—O1	169.3 (2)
N3—N4—C7—N1	0.0 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···O1ⁱ	1.28	1.28	2.561 (3)	180
N5—H5A···O2ⁱⁱ	0.80 (8)	2.09 (8)	2.815 (4)	151 (7)
N5—H5B···O1ⁱⁱⁱ	0.84 (11)	2.15 (10)	2.8513 (18)	140 (9)

Symmetry codes: (i) −x+1, −y−2, −z+1; (ii) x+1/2, −y−1, z; (iii) −x+3/2, y+1, −z+1.

Acknowledgements

The authors acknowledge St. Catherine University and NSF-MRI award No. 1125975 `MRI Consortium: Acquisition of a Single Crystal X-ray Diffractometer for a Regional PUI Molecular Structure Facility', as well as an NSF–CHE award No. 1308655 `Quantification and Visualization of the Prenylome'.

References

Burla, M. C., Caliandro, R., Camalli, M., Carrozzini, B., Cascarano, G. L., De Caro, L., Giacovazzo, C., Polidori, G. & Spagna, R. (2005). J. Appl. Cryst. 38, 381–388. Web of Science CrossRef CAS IUCr Journals Google Scholar
Chowdhury, M. & Kariuki, B. M. (2006). Cryst. Growth Des. 6, 774–780. Web of Science CSD CrossRef CAS Google Scholar
Gilli, P., Pretto, L., Bertolasi, V. & Gilli, G. (2009). Acc. Chem. Res. 42, 33–44. Web of Science CrossRef PubMed CAS Google Scholar
Golic, L. & Lazarini, F. (1975). Cryst. Struct. Commun. 4, 487–490. CAS Google Scholar
Ichikawa, M. (1972). Acta Cryst. B28, 755–760. CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
Ito, S., Tanaka, Y., Kakehi, A. & Kondo, K. (1976). Bull. Chem. Soc. Jpn, 49, 1920–1923. CrossRef CAS Web of Science Google Scholar
Lim, R. K. & Lin, Q. (2011). Acc. Chem. Res. 44, 828–839. Web of Science CrossRef CAS PubMed Google Scholar
Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Nahringbauer, I. (1969). Acta Chem. Scand. 23, 1653–1666. CrossRef CAS Web of Science Google Scholar
Perumalla, S. R. & Sun, C. C. (2013). CrystEngComm, 15, 5756–1559. Web of Science CSD CrossRef CAS Google Scholar
Ramil, C. P. & Lin, Q. (2014). Curr. Opin. Chem. Biol. 21, 89–95. Web of Science CrossRef CAS PubMed Google Scholar
Rigaku (1998). REQAB. Rigaku Corporation, Tokyo, Japan. Google Scholar
Rigaku (2011). CrystalClear-SM Expert. Rigaku Corporation, Tokyo, Japan. Google Scholar
Rigaku (2014). CrystalStructure. Rigaku Corporation, Tokyo, Japan. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Song, W., Wang, Y., Qu, J. & Lin, Q. (2008). J. Am. Chem. Soc. 130, 9654–9655. Web of Science CrossRef PubMed CAS Google Scholar
Zheng, S.-L., Wang, Y., Yu, Z., Lin, Q. & Coppens, P. J. (2009). J. Am. Chem. Soc. 131, 18036–18037. Web of Science CSD CrossRef PubMed CAS Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.