(2S,7S)-10-Ethyl-1,8,10,12-tetra­aza­tetra­cyclo­[8.3.1.18,12.02,7]penta­decan-10-ium iodide

Rivera, A.; Osorio, H.J.; Sadat-Bernal, J.; Eigner, V.; Dušek, M.

doi:10.1107/S1600536812040159

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 68| Part 10| October 2012| Pages o3041-o3042

https://doi.org/10.1107/S1600536812040159

Open

access

(2S,7S)-10-Ethyl-1,8,10,12-tetraazatetracyclo[8.3.1.1^8,12.0^2,7]pentadecan-10-ium iodide

Augusto Rivera,^a ^* Héctor Jairo Osorio,^b John Sadat-Bernal,^a Václav Eigner ^c ‡ and Michal Dušek ^d

^aUniversidad Nacional de Colombia, Sede Bogotá, Facultad de Ciencias, Departamento de Química, Cra 30 No.45-03, Bogotá, Código Postal 111321, Colombia, ^bUniversidad Nacional de Colombia, Sede Manizales, Colombia, ^cDepartment of Solid State Chemistry, Institute of Chemical Technology, Technická 5, 166 28 Prague, Czech Republic, and ^dInstitute of Physics ASCR, v.v.i., Na Slovance 2, 182 21 Praha 8, Czech Republic
^*Correspondence e-mail: ariverau@unal.edu.co

(Received 13 August 2012; accepted 21 September 2012; online 29 September 2012)

The title chiral quaternary ammonium salt, C₁₃H₂₅N₄⁺·I⁻, was synthesized through the Menschutkin reaction between the cage aminal (2S,7S)-1,8,10,12-tetraazatetracyclo[8.3.1.1^8,12.0^2,7]pentadecane and ethyl iodide. The quaternization occurred regioselectively on the nitrogen with major sp3 character. The crystal structure consists of anions and cations separated by normal distances. Ions are not linked through C—H⋯I hydrogen bonds.

Related literature

For related structures, see: Becka et al. (1963 ); Rivera et al. (2011b ,c ); Rivera, Sadat-Bernal et al. (2012 ). For the synthesis of the precursor (2S,7S)-1,8,10,12-tetraazatetracyclo [8.3.1.1^8,12.0^2,7]pentadecane, see: Rivera, Quiroga et al. (2012 ). For the preparation of the title salt, see: Rivera et al. (2011a ). For bond-length data, see: Allen et al. (1987 ). For the structural consequences of the anomeric effect, see: Kakanejadifard & Farnia (1997 ); Rivera et al. (2011b). For synthetic applications of chiral quaternary ammonium salts, see: Lygo Andrews (2004 ); Park et al. (2004 ); Kim & Huh (2001 ).

Experimental

Crystal data

C₁₃H₂₅N₄⁺·I⁻
M_r = 364.3
Orthorhombic, P 2₁ 2₁ 2₁
a = 10.2227 (5) Å
b = 12.0375 (6) Å
c = 12.0941 (6) Å
V = 1488.25 (13) Å³
Z = 4
Mo Kα radiation
μ = 2.14 mm⁻¹
T = 120 K
0.24 × 0.06 × 0.04 mm

Data collection

Agilent Xcalibur (Atlas, Gemini ultra) diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2010 ) T_min = 0.746, T_max = 1
5935 measured reflections
3223 independent reflections
3093 reflections with I > 3σ(I)
R_int = 0.016

Refinement

R[F² > 2σ(F²)] = 0.017
wR(F²) = 0.041
S = 1.19
3223 reflections
164 parameters
H-atom parameters constrained
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.47 e Å⁻³
Absolute structure: Flack (1983 ), 1353 Friedel pairs
Flack parameter: 0.026 (15)

Data collection: CrysAlis PRO (Agilent, 2010); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: Superflip (Palatinus & Chapuis, 2007 ); program(s) used to refine structure: JANA2006 (Petříček et al., 2006 ); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ); software used to prepare material for publication: JANA2006.

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536812040159/bh2451sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536812040159/bh2451Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S1600536812040159/bh2451Isup3.cml

checkCIF report

Comment top

The aminal (2S,7S)-1,8,10,12-tetraazatetracyclo [8.3.1.1^8,12.0^2,7]pentadecane is interesting because it presents a chiral molecular structure, which contains two pairs of non equivalent nitrogen atoms. (Rivera, Quiroga et al., 2012). Employing the method described, (Rivera et al., 2011a) the title compound (I) was readily prepared from (2S,7S)-1,8,10,12-tetraazatetracyclo [8.3.1.1^8,12.0^2,7]pentadecane by alkylation with iodo ethane in dry acetonitrile, at room temperature. The chiral quaternary ammonium salts are used as asymmetric phase-transfer catalysis (Lygo Andrews, 2004) and enantioselective reactions (Kim & Huh, 2001; Park et al., 2004).The molecular structure and atom-numbering scheme for (I) are shown in Fig 1.

The compound (I) crystallizes in the orthorhombic P2₁2₁2₁ chiral space group. The asymmetric unit of title molecule, C₁₃H₂₅N₄⁺.I^-, contains 10-ethyl-(2S,7S)-1,8,10,12-tetraazatetracyclo- [8.3.1.1^8,12.0^2,7]pentadecan-10-ium cation and one iodide anion. The N-monoalkylation produces ions where one nitrogen atom carries a full positive charge resulting in a distortion of the bond lengths and angles in the heterocyclic ring, compared to the molecular structure in the solid state of hexamethylenetetramine (Becka et al., 1963). The C—N distances and bond angles (C—N—C and N—C—N) vary from 1.426 (3) to 1.575 (3) Å and from 104.97 (15) to 118.54 (16)°, respectively.

Crystallographic data indicate the existence of an anomeric effect (Kakanejadifard & Farnia, 1997; Rivera et al., 2011b) in (I), manifest in the following facts: a lengthening of N4—C bond lengths [N4—C3, 1.575 (3) Å; N4—C5, 1.531 (3) Å; N4—C15, 1.529 (3) Å], and shortening of bond lengths N4C—N [C3—N2, 1.432 (3) Å; C5—N6, 1.426 (3) Å; C15—N13, 1.434 (3) Å] comparable with normal bond distances (Allen et al., 1987). Distortion of the C—N—C bond angles decreased the p character of non charged N atoms and reduces the N-pyramidality [α (CNC) around N2 = 341.47°; N6 = 342.22°; N13 = 332.7°] as occurring in other aminal derived salts (Rivera et al., 2011b,c; Rivera, Sadat-Bernal et al., 2012).The geometry of the N—C—C—N moiety is close to the syn-periplanar conformation, evidenced by the N2—C1—C7—N6 torsion angle, 37.7 (2)°. The organization of the crystal packing for the title compound exhibits a network connecting ions through C—H···I and C—H···C short contacts (Fig. 2).

Related literature top

For related structures, see: Becka et al. (1963); Rivera et al. (2011b,c); Rivera, Sadat-Bernal et al. (2012). For the synthesis of the precursor (2S,7S)-1,8,10,12-tetraazatetracyclo [8.3.1.1^8,12.0^2,7]pentadecane, see: Rivera, Quiroga et al. (2012). For the preparation of the title salt, see: Rivera et al. (2011a). For bond-length data, see: Allen et al. (1987). For the structural consequences of the anomeric effect, see: Kakanejadifard & Farnia (1997); Rivera et al. (2011b). For synthetic applications of chiral quaternary ammonium salts, see: Lygo Andrews (2004); Park et al. (2004); Kim & Huh (2001).

Experimental top

Preparation of 10-ethyl-(2S,7S)-1,8,10,12-tetraazatetracyclo [8.3.1.1^8,12.0^2,7] pentadecan-10-ium iodide

The title compound was synthesized according to the published procedure (Rivera et al., 2011a) by reacting (2S,7S)-1,8,10,12-tetraazatetracyclo[8.3.1.1^8,12.0^2,7]pentadecane and iodoethane. After work up a solid was obtained and then dissolved in water. After standing for several days at room temperature, crystals suitable for X-ray diffraction were obtained in 45% yield. Mp = 450–452 K.

Structure description top

For related structures, see: Becka et al. (1963); Rivera et al. (2011b,c); Rivera, Sadat-Bernal et al. (2012). For the synthesis of the precursor (2S,7S)-1,8,10,12-tetraazatetracyclo [8.3.1.1^8,12.0^2,7]pentadecane, see: Rivera, Quiroga et al. (2012). For the preparation of the title salt, see: Rivera et al. (2011a). For bond-length data, see: Allen et al. (1987). For the structural consequences of the anomeric effect, see: Kakanejadifard & Farnia (1997); Rivera et al. (2011b). For synthetic applications of chiral quaternary ammonium salts, see: Lygo Andrews (2004); Park et al. (2004); Kim & Huh (2001).

Computing details top

Data collection: CrysAlis PRO (Agilent, 2010); cell refinement: CrysAlis PRO (Agilent, 2010); data reduction: CrysAlis PRO (Agilent, 2010); program(s) used to solve structure: Superflip (Palatinus & Chapuis, 2007); program(s) used to refine structure: JANA2006 (Petříček et al., 2006); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: JANA2006 (Petříček et al., 2006).

Figures top

	Fig. 1. A view of (I) with the numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. Packing of the ions of the title compound viewed along a axis. C—H···I and C—H···C short contacts are drawn as dashed lines.

(2S,7S)-10-Ethyl-1,8,10,12- tetraazatetracyclo[8.3.1.1^8,12.0^2,7]pentadecan-10-ium iodide top

Crystal data top

C₁₃H₂₅N₄⁺·I⁻	D_x = 1.625 Mg m⁻³
M_r = 364.3	Melting point: 450 K
Orthorhombic, P2₁2₁2₁	Mo Kα radiation, λ = 0.7107 Å
Hall symbol: P 2ac 2ab	Cell parameters from 3457 reflections
a = 10.2227 (5) Å	θ = 3.1–27.0°
b = 12.0375 (6) Å	µ = 2.14 mm⁻¹
c = 12.0941 (6) Å	T = 120 K
V = 1488.25 (13) Å³	Prism, colourless
Z = 4	0.24 × 0.06 × 0.04 mm
F(000) = 736

Data collection top

Agilent Xcalibur (Atlas, Gemini ultra) diffractometer	3223 independent reflections
Radiation source: Enhance (Mo) X-ray Source	3093 reflections with I > 3σ(I)
Graphite monochromator	R_int = 0.016
Detector resolution: 10.3784 pixels mm^-1	θ_max = 27.1°, θ_min = 3.1°
ω scans	h = −13→9
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2010)	k = −14→15
T_min = 0.746, T_max = 1	l = −10→15
5935 measured reflections

Refinement top

Refinement on F²	H-atom parameters constrained
R[F > 3σ(F)] = 0.017	Weighting scheme based on measured s.u.'s w = 1/(σ²(I) + 0.0004I²)
wR(F) = 0.041	(Δ/σ)_max = 0.018
S = 1.19	Δρ_max = 0.23 e Å⁻³
3223 reflections	Δρ_min = −0.47 e Å⁻³
164 parameters	Absolute structure: Flack (1983), 1353 Friedel pairs
0 restraints	Absolute structure parameter: 0.026 (15)
0 constraints

Crystal data top

C₁₃H₂₅N₄⁺·I⁻	V = 1488.25 (13) Å³
M_r = 364.3	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 10.2227 (5) Å	µ = 2.14 mm⁻¹
b = 12.0375 (6) Å	T = 120 K
c = 12.0941 (6) Å	0.24 × 0.06 × 0.04 mm

Data collection top

Agilent Xcalibur (Atlas, Gemini ultra) diffractometer	3223 independent reflections
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2010)	3093 reflections with I > 3σ(I)
T_min = 0.746, T_max = 1	R_int = 0.016
5935 measured reflections

Refinement top

R[F > 3σ(F)] = 0.017	H-atom parameters constrained
wR(F) = 0.041	Δρ_max = 0.23 e Å⁻³
S = 1.19	Δρ_min = −0.47 e Å⁻³
3223 reflections	Absolute structure: Flack (1983), 1353 Friedel pairs
164 parameters	Absolute structure parameter: 0.026 (15)
0 restraints

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

	x	y	z	U_iso*/U_eq
I1	0.995575 (12)	0.462386 (9)	0.966324 (9)	0.01806 (4)
C1	0.4852 (2)	0.29285 (13)	0.73421 (15)	0.0153 (5)
N2	0.36266 (17)	0.33495 (15)	0.78149 (16)	0.0157 (5)
C3	0.2959 (2)	0.26756 (17)	0.86111 (18)	0.0170 (6)
N4	0.20151 (16)	0.17701 (14)	0.81134 (14)	0.0141 (5)
C5	0.2742 (2)	0.08504 (16)	0.74916 (17)	0.0146 (6)
N6	0.35735 (17)	0.12860 (15)	0.66504 (15)	0.0148 (5)
C7	0.4840 (2)	0.16841 (14)	0.70831 (15)	0.0142 (5)
C8	0.6008 (2)	0.13825 (18)	0.63737 (19)	0.0198 (7)
C9	0.7262 (2)	0.16905 (18)	0.6984 (2)	0.0213 (7)
C10	0.7278 (2)	0.28974 (16)	0.73715 (19)	0.0212 (7)
C11	0.6056 (2)	0.31806 (19)	0.8036 (2)	0.0180 (6)
C12	0.2718 (2)	0.37477 (18)	0.69715 (19)	0.0211 (6)
N13	0.19918 (17)	0.28513 (15)	0.64344 (16)	0.0194 (5)
C14	0.2834 (2)	0.20109 (17)	0.58957 (18)	0.0191 (6)
C15	0.1162 (2)	0.23336 (18)	0.72399 (18)	0.0186 (6)
C16	0.1232 (2)	0.13179 (17)	0.90618 (18)	0.0203 (6)
C17	0.0267 (2)	0.04169 (19)	0.87726 (19)	0.0289 (7)
H1c1	0.490912	0.333228	0.66593	0.0183*
H1c3	0.247872	0.314369	0.91096	0.0204*
H2c3	0.358654	0.232404	0.908641	0.0204*
H1c5	0.325356	0.042413	0.80047	0.0175*
H2c5	0.212023	0.035003	0.716646	0.0175*
H1c7	0.493127	0.128663	0.776687	0.017*
H1c8	0.600074	0.059842	0.62289	0.0237*
H2c8	0.596557	0.178345	0.568841	0.0237*
H1c9	0.800126	0.155718	0.651276	0.0256*
H2c9	0.737333	0.120781	0.760916	0.0256*
H1c10	0.804004	0.302556	0.781695	0.0254*
H2c10	0.733483	0.338024	0.674158	0.0254*
H1c11	0.606624	0.395538	0.822422	0.0216*
H2c11	0.603662	0.274033	0.869799	0.0216*
H1c12	0.211459	0.426301	0.729818	0.0254*
H2c12	0.319	0.416333	0.642393	0.0254*
H1c14	0.23152	0.156343	0.540652	0.0229*
H2c14	0.342843	0.237356	0.539822	0.0229*
H1c15	0.062251	0.178719	0.688439	0.0224*
H2c15	0.062416	0.288707	0.7586	0.0224*
H1c16	0.078397	0.191556	0.9426	0.0243*
H2c16	0.181437	0.105459	0.962693	0.0243*
H1c17	−0.019759	0.019483	0.942586	0.0346*
H2c17	−0.034168	0.069235	0.823415	0.0346*
H3c17	0.072673	−0.021042	0.847344	0.0346*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
I1	0.01928 (7)	0.01921 (7)	0.01568 (7)	0.00180 (7)	0.00111 (8)	0.00244 (4)
C1	0.0163 (11)	0.0137 (9)	0.0159 (8)	−0.0011 (8)	−0.0006 (11)	−0.0009 (7)
N2	0.0173 (9)	0.0108 (9)	0.0188 (10)	0.0020 (7)	0.0016 (8)	0.0008 (8)
C3	0.0184 (10)	0.0152 (10)	0.0174 (10)	0.0000 (8)	0.0010 (9)	−0.0024 (8)
N4	0.0139 (9)	0.0150 (9)	0.0133 (8)	−0.0001 (7)	0.0012 (8)	0.0007 (7)
C5	0.0180 (10)	0.0118 (10)	0.0140 (10)	−0.0001 (8)	0.0006 (9)	−0.0012 (8)
N6	0.0158 (9)	0.0147 (9)	0.0138 (9)	−0.0025 (7)	−0.0021 (8)	0.0006 (7)
C7	0.0168 (11)	0.0124 (8)	0.0132 (8)	−0.0004 (9)	−0.0006 (10)	0.0005 (7)
C8	0.0216 (11)	0.0155 (11)	0.0222 (12)	−0.0011 (9)	0.0048 (10)	−0.0031 (9)
C9	0.0167 (11)	0.0211 (12)	0.0260 (12)	0.0019 (9)	0.0039 (10)	−0.0022 (10)
C10	0.0165 (11)	0.0212 (12)	0.0257 (12)	−0.0032 (8)	−0.0022 (10)	−0.0010 (10)
C11	0.0203 (11)	0.0150 (11)	0.0187 (11)	−0.0033 (9)	0.0002 (10)	−0.0007 (9)
C12	0.0218 (11)	0.0143 (11)	0.0274 (11)	0.0025 (9)	0.0003 (10)	0.0061 (9)
N13	0.0180 (9)	0.0201 (9)	0.0200 (9)	0.0011 (7)	−0.0001 (8)	0.0059 (7)
C14	0.0218 (11)	0.0234 (11)	0.0121 (10)	−0.0023 (9)	−0.0013 (9)	0.0027 (9)
C15	0.0147 (11)	0.0216 (11)	0.0196 (11)	0.0034 (8)	−0.0044 (9)	0.0028 (9)
C16	0.0206 (11)	0.0254 (12)	0.0148 (10)	−0.0005 (9)	0.0045 (9)	0.0005 (9)
C17	0.0255 (12)	0.0346 (12)	0.0265 (11)	−0.0074 (11)	0.0048 (10)	0.0037 (9)

Geometric parameters (Å, º) top

C1—C7	1.530 (2)	C9—H2c9	0.96
C1—C11	1.521 (3)	C10—C9	1.527 (3)
C1—H1c1	0.96	C10—C11	1.524 (3)
N2—C1	1.467 (3)	C10—H1c10	0.96
N2—C3	1.432 (3)	C10—H2c10	0.96
N2—C12	1.460 (3)	C11—H1c11	0.96
C3—H1c3	0.96	C11—H2c11	0.96
C3—H2c3	0.96	C12—H1c12	0.96
N4—C3	1.575 (3)	C12—H2c12	0.96
N4—C5	1.531 (3)	N13—C12	1.462 (3)
N4—C15	1.529 (3)	N13—C14	1.480 (3)
N4—C16	1.501 (3)	N13—C15	1.434 (3)
C5—H1c5	0.96	C14—H1c14	0.96
C5—H2c5	0.96	C14—H2c14	0.96
N6—C5	1.426 (3)	C15—H1c15	0.96
N6—C7	1.476 (3)	C15—H2c15	0.96
N6—C14	1.472 (3)	C16—H1c16	0.96
C7—H1c7	0.96	C16—H2c16	0.96
C8—C7	1.514 (3)	C17—C16	1.507 (3)
C8—C9	1.526 (3)	C17—H1c17	0.96
C8—H1c8	0.96	C17—H2c17	0.96
C8—H2c8	0.96	C17—H3c17	0.96
C9—H1c9	0.96

N2—C1—C7	114.27 (17)	H1c9—C9—H2c9	105.87
N2—C1—C11	114.02 (16)	C9—C10—H1c10	109.47
N2—C1—H1c1	102.26	C9—C10—H2c10	109.47
C7—C1—C11	108.35 (17)	C11—C10—C9	111.49 (18)
C7—C1—H1c1	108.66	C11—C10—H1c10	109.47
C11—C1—H1c1	108.95	C11—C10—H2c10	109.47
C1—N2—C3	118.26 (16)	H1c10—C10—H2c10	107.37
C1—N2—C12	112.59 (17)	C1—C11—C10	109.11 (18)
C12—N2—C3	110.62 (17)	C1—C11—H1c11	109.47
N2—C3—N4	115.28 (17)	C1—C11—H2c11	109.47
N2—C3—H1c3	109.47	C10—C11—H1c11	109.47
N2—C3—H2c3	109.47	C10—C11—H2c11	109.47
N4—C3—H1c3	109.47	H1c11—C11—H2c11	109.83
N4—C3—H2c3	109.47	N2—C12—N13	113.02 (17)
H1c3—C3—H2c3	102.97	N2—C12—H1c12	109.47
C3—N4—C5	113.01 (15)	N2—C12—H2c12	109.47
C3—N4—C15	107.85 (15)	N13—C12—H1c12	109.47
C3—N4—C16	106.58 (15)	N13—C12—H2c12	109.47
C5—N4—C15	104.97 (15)	H1c12—C12—H2c12	105.67
C16—N4—C5	111.84 (15)	C12—N13—C14	113.87 (17)
C16—N4—C15	112.64 (15)	C12—N13—C15	108.62 (17)
N4—C5—H1c5	109.47	C14—N13—C15	110.25 (17)
N4—C5—H2c5	109.47	N6—C14—N13	115.54 (18)
N6—C5—N4	111.96 (16)	N6—C14—H1c14	109.47
N6—C5—H1c5	109.47	N6—C14—H2c14	109.47
N6—C5—H2c5	109.47	N13—C14—H1c14	109.47
H1c5—C5—H2c5	106.87	N13—C14—H2c14	109.47
C7—N6—C5	112.91 (16)	H1c14—C14—H2c14	102.63
C7—N6—C14	118.54 (16)	N4—C15—H1c15	109.47
C14—N6—C5	110.77 (16)	N4—C15—H2c15	109.47
C1—C7—H1c7	108.1	N13—C15—N4	108.96 (17)
N6—C7—C1	113.40 (17)	N13—C15—H1c15	109.47
N6—C7—C8	114.37 (16)	N13—C15—H2c15	109.47
N6—C7—H1c7	103.22	H1c15—C15—H2c15	109.98
C8—C7—C1	110.15 (17)	N4—C16—C17	115.63 (18)
C8—C7—H1c7	106.98	N4—C16—H1c16	109.47
C7—C8—C9	109.28 (18)	N4—C16—H2c16	109.47
C7—C8—H1c8	109.47	C17—C16—H1c16	109.47
C7—C8—H2c8	109.47	C17—C16—H2c16	109.47
C9—C8—H1c8	109.47	H1c16—C16—H2c16	102.52
C9—C8—H2c8	109.47	C16—C17—H1c17	109.47
H1c8—C8—H2c8	109.66	C16—C17—H2c17	109.47
C8—C9—C10	112.85 (18)	C16—C17—H3c17	109.47
C8—C9—H1c9	109.47	H1c17—C17—H2c17	109.47
C8—C9—H2c9	109.47	H1c17—C17—H3c17	109.47
C10—C9—H1c9	109.47	H2c17—C17—H3c17	109.47
C10—C9—H2c9	109.47

Experimental details

Crystal data
Chemical formula	C₁₃H₂₅N₄⁺·I⁻
M_r	364.3
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	120
a, b, c (Å)	10.2227 (5), 12.0375 (6), 12.0941 (6)
V (Å³)	1488.25 (13)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	2.14
Crystal size (mm)	0.24 × 0.06 × 0.04

Data collection
Diffractometer	Agilent Xcalibur (Atlas, Gemini ultra)
Absorption correction	Multi-scan (CrysAlis PRO; Agilent, 2010)
T_min, T_max	0.746, 1
No. of measured, independent and observed [I > 3σ(I)] reflections	5935, 3223, 3093
R_int	0.016
(sin θ/λ)_max (Å⁻¹)	0.641

Refinement
R[F > 3σ(F)], wR(F), S	0.017, 0.041, 1.19
No. of reflections	3223
No. of parameters	164
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.23, −0.47
Absolute structure	Flack (1983), 1353 Friedel pairs
Absolute structure parameter	0.026 (15)

Computer programs: CrysAlis PRO (Agilent, 2010), Superflip (Palatinus & Chapuis, 2007), JANA2006 (Petříček et al., 2006), DIAMOND (Brandenburg & Putz, 2005), JANA2006 (Petříček et al., 2006).

Footnotes

‡Other affiliation: Institute of Physics ASCR, v.v.i., Na Slovance 2, 182 21 Praha 8, Czech Republic.

Acknowledgements

We acknowledge the Dirección de Investigaciones, Sede Bogotá (DIB) y Sede Manizales (DIMA) de la Universidad Nacional de Colombia, for financial support of this work, as well as the Institutional research plan No. AVOZ10100521 of the Institute of Physics and the Praemium Academiae project of the Academy of Sciences of the Czech Republic (ASCR).

References

Agilent (2010). CrysAlis PRO. Agilent Technologies, Yarnton, England. Google Scholar
Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19. CSD CrossRef Web of Science Google Scholar
Becka, L. N. & Cruickshank, D. W. J. (1963). Proc. R. Soc. London Ser. A, 273, 435–455. CSD CrossRef CAS Web of Science Google Scholar
Brandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Kakanejadifard, A. & Farnia, S. M. F. (1997). Tetrahedron, 53, 2551–2556. CSD CrossRef CAS Web of Science Google Scholar
Kim, D. Y. & Huh, S. C. (2001). Tetrahedron, 57, 8933–8938. Web of Science CrossRef CAS Google Scholar
Lygo, B. & Andrews, B. I. (2004). Acc. Chem. Res. 37, 518–525. Web of Science CrossRef PubMed CAS Google Scholar
Palatinus, L. & Chapuis, G. (2007). J. Appl. Cryst. 40, 786–790. Web of Science CrossRef CAS IUCr Journals Google Scholar
Park, E. J., Kim, M. H. & Kim, D. Y. (2004). J. Org. Chem. 69, 6897–6899. Web of Science CrossRef PubMed CAS Google Scholar
Petříček, V., Dusěk, M. & Palatinus, L. (2006). JANA2006. Institute of Physics, Praha, Czech Republic. Google Scholar
Rivera, A., Quiroga, D., Jiménez-Cruz, L., Fejfarová, K. & Dušek, M. (2012). Tetrahedron Lett. 53, 345–348. Web of Science CSD CrossRef CAS Google Scholar
Rivera, A., Sadat-Bernal, J., Ríos-Motta, J., Dušek, M. & Fejfarová, K. (2011b). J. Chem. Crystallogr. 41, 591–595. Web of Science CSD CrossRef CAS Google Scholar
Rivera, A., Sadat-Bernal, J., Ríos-Motta, J., Dušek, M. & Palatinus, L. (2011a). Chem. Cent. J. 5, article number 55. Web of Science CSD CrossRef Google Scholar
Rivera, A., Sadat-Bernal, J., Ríos-Motta, J., Fejfarová, K. & Dušek, M. (2011c). Acta Cryst. E67, o2629. Web of Science CSD CrossRef IUCr Journals Google Scholar
Rivera, A., Sadat-Bernal, J., Ríos-Motta, J., Fejfarová, K. & Dušek, M. (2012). Acta Cryst. E68, o17. Web of Science CSD CrossRef IUCr Journals 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.