4-Bromo-β-(2-oxoquinolin-4-yl­oxy)cinnamonitrile: a three-dimensional framework structure built from N—H⋯O and C—H⋯O hydrogen bonds, and bromo–carbonyl and aromatic π–π stacking inter­actions

Cruz, S.; Torre, J.M. de la; Cobo, J.; Low, J.N.; Glidewell, C.

doi:10.1107/S1600536806023518

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 62| Part 7| July 2006| Pages o3056-o3058

https://doi.org/10.1107/S1600536806023518

4-Bromo-β-(2-oxoquinolin-4-yloxy)cinnamonitrile: a three-dimensional framework structure built from N—H⋯O and C—H⋯O hydrogen bonds, and bromo–carbonyl and aromatic π–π stacking interactions

Silvia Cruz,^a José M. de la Torre,^b Justo Cobo,^b John N. Low ^c and Christopher Glidewell ^d ^*

^aDepartamento de Química, Universidad de Nariño, Ciudad Universitaria, Torobajo, AA 1175, Pasto, Colombia, ^bDepartamento de Química Inorgánica y Orgánica, Universidad de Jaén, 23071 Jaén, Spain, ^cDepartment of Chemistry, University of Aberdeen, Meston Walk, Old Aberdeen AB24 3UE, Scotland, and ^dSchool of Chemistry, University of St Andrews, Fife KY16 9ST, Scotland
^*Correspondence e-mail: cg@st-andrews.ac.uk

(Received 19 June 2006; accepted 19 June 2006; online 28 June 2006)

In the title compound, C₁₈H₁₁BrN₂O₂, the molecules are linked into sheets by a combination of one N—H⋯O and two C—H⋯O hydrogen bonds, and the sheets are linked by an aromatic π–π stacking interaction.

Comment

The title compound, (I), has been prepared from 2,4-dihydroxyquinoline and 4-bromo-β-chlorocinnamonitrile as a potential intermediate for the synthesis of fused quinoline derivatives.

The molecules of compound (I) show a significant deviation from planarity, as shown by the key torsion angles (Table 1). The biggest deviation from planarity is associated with the rotation of the two effectively planar components of the molecule about the O4—C17 bond, which is probably driven by the repulsive interaction between the cyano substituent and the H atom bonded to C3 (Fig. 1). Consistent with this, the bond angle at O4 is abnormally large.

While the C—C distances within the brominated aryl ring span only a rather narrow range [1.383 (3) − 1.400 (3) Å with mean value 1.389 Å], the distances in the other carbocyclic ring show evidence of some bond fixation, with bonds C5—C6 and C7—C8 significantly shorter than the remainder.

The molecules of compound (I) are linked by paired N—H⋯O hydrogen bonds (Table 2) into centrosymmetric R₂²(8) (Bernstein et al., 1995 ) dimers, and the reference molecule was selected so that it forms part of a dimer centred at ( $[1\over2]$ , $[1\over2]$ , $[1\over2]$ ) (Fig. 2). Atoms C12 and C18 in the molecule at (x, y, z) both act as hydrogen bond donors to atom O2 in the molecule at ( $[3\over2]$ − x, − $[{1\over 2}]$ + y, $[3\over2]$ − z), in an R₂¹(7) motif. Propagation by the space group of these interactions then links the dimer centred at (1/2, 1/2, 1/2) as donor to those centred at (1, 0, 1) and (0, 1, 0), and as acceptor from those centred at (0, 0, 0) and (1, 1, 1), thereby forming a (10 $[\overline{1}]$ ) sheet built from R₂¹(7), R₂²(8) and R₆⁶(36) rings (Fig. 3).

The rings C4A/C5–C8/C8A in the molecules at (x, y, z) and (2 − x, 1 − y, 1 − z) form parts of the R₂²(8) dimers centred at ( $[1\over2]$ , $[1\over2]$ , $[1\over2]$ ) and ( $[3\over2]$ , $[1\over2]$ , $[1\over2]$ ), respectively. These rings are strictly parallel with an interplanar spacing of 3.439 (2) Å: the corresponding ring-centroid separation is 3.799 (2) and the ring offset is 1.614 (2) Å. The effect of this interaction is to link the sheets along the [100] direction (Fig. 4), so forming a continuous three-dimensional structure.

The Br atom at (x, y, z) makes a short contact with the amide atom O2 in the molecule at (1 − x, −y, 1 − z), with Br⋯Oⁱⁱⁱ = 3.078 (2) Å and C—Br⋯Oⁱⁱⁱ = 164.3 (2)° [symmetry code: (iii) 1 − x, −y, 1 − z] and this weakly attractive bromo–carbonyl interaction links the hydrogen-bonded dimers into a chain of edge-fused R₂²(8) and R₂²(22) rings (Bernstein et al., 1995; Starbuck et al., 1999 ) along [010], further reinforcing the framework (Fig. 5).

Figure 1
The molecular structure of (I)

, showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.

Figure 2
Part of the crystal structure of (I)

, showing the formation of a hydrogen-bonded R₂²(8) dimer. Dashed lines indicate hydrogen bonds. For the sake of clarity, H atoms bonded to C atoms have been omitted. Atoms marked with an asterisk (*) are at the symmetry position (1 − x, 1 − y, 1 − z).

Figure 3
A stereoscopic view of part of the crystal structure of (I)

, showing the formation of a hydrogen-bonded (10 $[\overline{1}]$ ) sheet. Dashed lines indicate hydrogen bonds. For the sake of clarity, H atoms not involved in the motifs shown have been omitted.

Figure 4
A stereoscopic view of part of the crystal structure of (I)

, showing the formation of a π-stacked chain of hydrogen-bonded dimers along [100], linking the (10 $[\overline{1}]$ ) sheets. Dashed lines indicate hydrogen bonds. For the sake of clarity, H atoms bonded to C atoms have been omitted.

Figure 5
A stereoscopic view of part of the crystal structure of (I)

, showing the formation of a [010] chain of edge-fused rings formed by hydrogen-bonded dimers linked by the Br⋯O contact. Dashed lines indicate hydrogen bonds and Br⋯O contacts. For the sake of clarity, H atoms bonded to C atoms have been omitted.

Experimental

A solution containing 4-bromo-β-chlorocinnamonitrile (1 mmol), 2,4-dihydroxyquinoline (1 mmol) and triethylamine (0.5 ml) in anhydrous ethanol (10 ml) was heated under reflux for 10 h. The resulting solid product was collected by filtration, washed with ethanol and recrystallized from ethanol to give pale-yellow crystals suitable for single-crystal X-ray diffraction (m.p. 582 K, yield 60%).

Crystal data

C₁₈H₁₁BrN₂O₂
M_r = 367.20
Monoclinic, P 2₁ /n
a = 8.9860 (2) Å
b = 12.4111 (3) Å
c = 13.6138 (3) Å
β = 92.006 (2)°
V = 1517.36 (6) Å³
Z = 4
D_x = 1.607 Mg m⁻³
Mo Kα radiation
μ = 2.72 mm⁻¹
T = 120 (2) K
Block, pale yellow
0.70 × 0.50 × 0.30 mm

Data collection

Bruker–Nonius KappaCCD diffractometer
φ and ω scans
Absorption correction: multi-scan (SADABS; Sheldrick, 2003 ) T_min = 0.224, T_max = 0.441
17684 measured reflections
3463 independent reflections
2907 reflections with I > 2σ(I)
R_int = 0.034
θ_max = 27.5°

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.032
wR(F²) = 0.080
S = 1.16
3463 reflections
208 parameters
H-atom parameters constrained
w = 1/[σ²(F_o²) + (0.033P)² + 1.024P] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max = 0.001
Δρ_max = 0.36 e Å⁻³
Δρ_min = −0.68 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

C4A—C5	1.404 (3)
C5—C6	1.372 (3)
C6—C7	1.403 (3)
C7—C8	1.375 (3)
C8—C8A	1.404 (3)
C8A—C4A	1.400 (3)

C4—O4—C17	119.34 (15)

C3—C4—O4—C17	26.0 (3)
C4—O4—C17—C18	−118.0 (2)
C4—O4—C17—C11	68.3 (2)
O4—C17—C11—C12	−176.79 (18)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O2ⁱ	0.88	1.96	2.814 (2)	164
C12—H12⋯O2ⁱⁱ	0.95	2.52	3.435 (2)	163
C18—H18⋯O2ⁱⁱ	0.95	2.44	3.389 (3)	178
Symmetry codes: (i) -x+1, -y+1, -z+1; (ii) $[-x+{\script{3\over 2}}, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ .

All H atoms were located in difference maps and then treated as riding atoms with C—H = 0.95 Å and N—H = 0.88 Å, and with U_iso(H) = 1.2U_eq(C,N).

Data collection: COLLECT (Hooft, 1999 ); cell refinement: DENZO (Otwinowski & Minor, 1997 ) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SIR2004 (Burla et al., 2005 ); program(s) used to refine structure: OSCAIL (McArdle, 2003 ) and SHELXL97 (Sheldrick, 1997 ); molecular graphics: PLATON (Spek, 2003 ); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536806023518/lh2107sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536806023518/lh2107Isup2.hkl

Computing details top

Data collection: COLLECT (Hooft, 1999); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: OSCAIL (McArdle, 2003) and SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).

4-Bromo-β-(2-oxoquinolin-4-yloxy)cinnamonitrile top

Crystal data top

C₁₈H₁₁BrN₂O₂	F(000) = 736
M_r = 367.20	D_x = 1.607 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 3463 reflections
a = 8.9860 (2) Å	θ = 3.1–27.5°
b = 12.4111 (3) Å	µ = 2.72 mm⁻¹
c = 13.6138 (3) Å	T = 120 K
β = 92.006 (2)°	Block, colourless
V = 1517.36 (6) Å³	0.70 × 0.50 × 0.30 mm
Z = 4

Data collection top

Bruker–Nonius KappaCCD diffractometer	3463 independent reflections
Radiation source: Bruker-Nonius FR591 rotating anode	2907 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.034
Detector resolution: 9.091 pixels mm^-1	θ_max = 27.5°, θ_min = 3.1°
φ and ω scans	h = −11→11
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	k = −16→15
T_min = 0.224, T_max = 0.441	l = −17→17
17684 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.080	H-atom parameters constrained
S = 1.16	w = 1/[σ²(F_o²) + (0.033P)² + 1.024P] where P = (F_o² + 2F_c²)/3
3463 reflections	(Δ/σ)_max = 0.001
208 parameters	Δρ_max = 0.36 e Å⁻³
0 restraints	Δρ_min = −0.68 e Å⁻³

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

	x	y	z	U_iso*/U_eq
N1	0.69050 (18)	0.45629 (14)	0.48541 (12)	0.0153 (3)
C2	0.6573 (2)	0.40615 (16)	0.57075 (14)	0.0145 (4)
O2	0.53963 (15)	0.42863 (12)	0.61305 (10)	0.0175 (3)
C3	0.7623 (2)	0.32710 (16)	0.60798 (15)	0.0152 (4)
C4	0.8893 (2)	0.30846 (16)	0.56033 (14)	0.0140 (4)
O4	0.99737 (15)	0.23650 (12)	0.59192 (10)	0.0163 (3)
C4A	0.9243 (2)	0.36467 (16)	0.47165 (15)	0.0145 (4)
C5	1.0543 (2)	0.34596 (17)	0.42009 (15)	0.0179 (4)
C6	1.0770 (2)	0.40041 (18)	0.33419 (16)	0.0217 (5)
C7	0.9722 (2)	0.47594 (18)	0.29849 (15)	0.0204 (4)
C8	0.8443 (2)	0.49569 (17)	0.34809 (15)	0.0180 (4)
C8A	0.8191 (2)	0.43912 (16)	0.43525 (14)	0.0146 (4)
C11	0.8644 (2)	0.06677 (16)	0.60203 (15)	0.0155 (4)
C12	0.8128 (2)	−0.02104 (17)	0.65539 (15)	0.0193 (4)
C13	0.7290 (3)	−0.10121 (18)	0.60951 (16)	0.0225 (5)
C14	0.6977 (2)	−0.09451 (18)	0.50928 (17)	0.0213 (5)
Br14	0.59176 (3)	−0.207817 (19)	0.445430 (18)	0.02971 (9)
C15	0.7466 (2)	−0.00827 (18)	0.45473 (16)	0.0212 (5)
C16	0.8295 (2)	0.07214 (17)	0.50110 (16)	0.0192 (4)
C17	0.9581 (2)	0.14977 (16)	0.64989 (15)	0.0155 (4)
C18	1.0206 (2)	0.14423 (17)	0.74090 (16)	0.0195 (4)
C19	1.1128 (3)	0.22890 (18)	0.77929 (16)	0.0235 (5)
H1	0.6256	0.5028	0.4605	0.018*
H3	0.7423	0.2880	0.6661	0.018*
H5	1.1264	0.2958	0.4446	0.021*
H6	1.1642	0.3869	0.2986	0.026*
H7	0.9898	0.5139	0.2394	0.025*
H8	0.7739	0.5470	0.3237	0.022*
H12	0.8354	−0.0257	0.7239	0.023*
H13	0.6934	−0.1603	0.6463	0.027*
H15	0.7236	−0.0043	0.3862	0.025*
H16	0.8630	0.1317	0.4640	0.023*
H18	1.0030	0.0827	0.7804	0.023*
N4	1.1869 (3)	0.29569 (16)	0.81204 (16)	0.0334 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0154 (8)	0.0145 (8)	0.0157 (8)	0.0024 (7)	−0.0023 (7)	0.0027 (7)
C2	0.0162 (9)	0.0134 (9)	0.0138 (10)	−0.0011 (8)	−0.0018 (7)	−0.0023 (8)
O2	0.0176 (7)	0.0191 (7)	0.0158 (7)	0.0037 (6)	0.0005 (6)	−0.0010 (6)
C3	0.0189 (10)	0.0141 (9)	0.0125 (10)	−0.0004 (8)	−0.0010 (8)	0.0004 (8)
C4	0.0165 (10)	0.0107 (9)	0.0146 (10)	−0.0001 (7)	−0.0045 (8)	−0.0014 (7)
O4	0.0151 (7)	0.0164 (7)	0.0171 (7)	0.0026 (6)	−0.0016 (6)	0.0044 (6)
C4A	0.0156 (10)	0.0124 (9)	0.0153 (10)	−0.0019 (8)	−0.0023 (8)	−0.0011 (8)
C5	0.0180 (10)	0.0185 (10)	0.0170 (10)	0.0014 (8)	−0.0015 (8)	0.0009 (8)
C6	0.0199 (10)	0.0247 (11)	0.0208 (11)	−0.0005 (9)	0.0035 (8)	−0.0004 (9)
C7	0.0246 (11)	0.0225 (11)	0.0141 (10)	−0.0058 (9)	0.0007 (8)	0.0041 (8)
C8	0.0192 (10)	0.0167 (10)	0.0179 (10)	−0.0018 (8)	−0.0038 (8)	0.0034 (8)
C8A	0.0151 (9)	0.0146 (9)	0.0138 (10)	−0.0029 (8)	−0.0027 (7)	−0.0020 (8)
C11	0.0151 (9)	0.0164 (10)	0.0148 (10)	0.0045 (8)	−0.0015 (8)	−0.0018 (8)
C12	0.0234 (10)	0.0203 (11)	0.0141 (10)	−0.0005 (9)	0.0010 (8)	0.0001 (8)
C13	0.0278 (11)	0.0186 (11)	0.0214 (11)	−0.0013 (9)	0.0056 (9)	0.0001 (9)
C14	0.0181 (10)	0.0191 (11)	0.0267 (12)	0.0005 (8)	−0.0016 (8)	−0.0047 (9)
Br14	0.02947 (14)	0.02552 (14)	0.03352 (15)	−0.00713 (10)	−0.00755 (10)	−0.00544 (10)
C15	0.0231 (11)	0.0231 (11)	0.0170 (11)	0.0021 (9)	−0.0057 (8)	−0.0016 (9)
C16	0.0212 (10)	0.0171 (10)	0.0191 (11)	0.0020 (8)	−0.0031 (8)	0.0031 (8)
C17	0.0168 (10)	0.0139 (10)	0.0159 (10)	0.0045 (8)	0.0008 (8)	0.0020 (8)
C18	0.0238 (11)	0.0156 (10)	0.0187 (11)	0.0000 (8)	−0.0039 (8)	0.0014 (8)
C19	0.0321 (12)	0.0218 (11)	0.0162 (11)	0.0031 (10)	−0.0071 (9)	0.0023 (9)
N4	0.0487 (13)	0.0248 (11)	0.0256 (11)	−0.0043 (10)	−0.0136 (10)	0.0017 (9)

Geometric parameters (Å, º) top

N1—C2	1.360 (3)	C8A—C4A	1.400 (3)
N1—C8A	1.379 (3)	C8—H8	0.95
N1—H1	0.88	C11—C12	1.398 (3)
C2—O2	1.253 (2)	C11—C16	1.400 (3)
C2—C3	1.441 (3)	C11—C17	1.468 (3)
C3—C4	1.352 (3)	C12—C13	1.383 (3)
C3—H3	0.95	C12—H12	0.95
C4—O4	1.377 (2)	C13—C14	1.386 (3)
C4—C4A	1.439 (3)	C13—H13	0.95
O4—C17	1.388 (2)	C14—C15	1.383 (3)
C4A—C5	1.404 (3)	C14—Br14	1.892 (2)
C5—C6	1.372 (3)	C15—C16	1.384 (3)
C5—H5	0.95	C15—H15	0.95
C6—C7	1.403 (3)	C16—H16	0.95
C6—H6	0.95	C17—C18	1.344 (3)
C7—C8	1.375 (3)	C18—C19	1.426 (3)
C7—H7	0.95	C18—H18	0.95
C8—C8A	1.404 (3)	C19—N4	1.144 (3)

C2—N1—C8A	124.39 (17)	N1—C8A—C4A	119.59 (18)
C2—N1—H1	117.8	N1—C8A—C8	120.28 (18)
C8A—N1—H1	117.8	C4A—C8A—C8	120.13 (19)
O2—C2—N1	120.30 (18)	C12—C11—C16	118.67 (19)
O2—C2—C3	122.87 (19)	C12—C11—C17	120.80 (18)
N1—C2—C3	116.83 (18)	C16—C11—C17	120.49 (19)
C4—C3—C2	120.07 (19)	C13—C12—C11	120.76 (19)
C4—C3—H3	120.0	C13—C12—H12	119.6
C2—C3—H3	120.0	C11—C12—H12	119.6
C3—C4—O4	123.99 (18)	C12—C13—C14	119.3 (2)
C3—C4—C4A	122.18 (18)	C12—C13—H13	120.3
O4—C4—C4A	113.83 (17)	C14—C13—H13	120.3
C4—O4—C17	119.34 (15)	C15—C14—C13	121.2 (2)
C8A—C4A—C5	119.73 (19)	C15—C14—Br14	119.51 (16)
C8A—C4A—C4	116.89 (18)	C13—C14—Br14	119.29 (17)
C5—C4A—C4	123.35 (18)	C14—C15—C16	119.3 (2)
C6—C5—C4A	119.72 (19)	C14—C15—H15	120.4
C6—C5—H5	120.1	C16—C15—H15	120.4
C4A—C5—H5	120.1	C15—C16—C11	120.8 (2)
C5—C6—C7	120.4 (2)	C15—C16—H16	119.6
C5—C6—H6	119.8	C11—C16—H16	119.6
C7—C6—H6	119.8	C18—C17—O4	117.23 (18)
C8—C7—C6	120.7 (2)	C18—C17—C11	125.99 (19)
C8—C7—H7	119.6	O4—C17—C11	116.43 (17)
C6—C7—H7	119.6	C17—C18—C19	121.3 (2)
C7—C8—C8A	119.24 (19)	C17—C18—H18	119.4
C7—C8—H8	120.4	C19—C18—H18	119.4
C8A—C8—H8	120.4	N4—C19—C18	178.5 (2)

C8A—N1—C2—O2	178.04 (18)	C4—C4A—C8A—C8	−178.90 (18)
C8A—N1—C2—C3	−2.5 (3)	C7—C8—C8A—N1	−178.94 (18)
O2—C2—C3—C4	−178.26 (18)	C7—C8—C8A—C4A	0.9 (3)
N1—C2—C3—C4	2.3 (3)	C16—C11—C12—C13	0.1 (3)
C2—C3—C4—O4	178.32 (17)	C17—C11—C12—C13	−177.63 (19)
C2—C3—C4—C4A	−0.6 (3)	C11—C12—C13—C14	0.7 (3)
C3—C4—O4—C17	26.0 (3)	C12—C13—C14—C15	−1.0 (3)
C4A—C4—O4—C17	−155.03 (17)	C12—C13—C14—Br14	176.84 (16)
C3—C4—C4A—C8A	−1.1 (3)	C13—C14—C15—C16	0.6 (3)
O4—C4—C4A—C8A	179.95 (16)	Br14—C14—C15—C16	−177.29 (16)
C3—C4—C4A—C5	−179.20 (19)	C14—C15—C16—C11	0.2 (3)
O4—C4—C4A—C5	1.8 (3)	C12—C11—C16—C15	−0.6 (3)
C8A—C4A—C5—C6	−0.3 (3)	C17—C11—C16—C15	177.18 (19)
C4—C4A—C5—C6	177.78 (19)	C4—O4—C17—C18	−118.0 (2)
C4A—C5—C6—C7	1.1 (3)	C4—O4—C17—C11	68.3 (2)
C5—C6—C7—C8	−0.9 (3)	C12—C11—C17—C18	10.1 (3)
C6—C7—C8—C8A	−0.1 (3)	C16—C11—C17—C18	−167.6 (2)
C2—N1—C8A—C4A	0.9 (3)	O4—C17—C11—C12	−176.79 (18)
C2—N1—C8A—C8	−179.29 (18)	C16—C11—C17—O4	5.5 (3)
C5—C4A—C8A—N1	179.16 (18)	O4—C17—C18—C19	5.5 (3)
C4—C4A—C8A—N1	0.9 (3)	C11—C17—C18—C19	178.5 (2)
C5—C4A—C8A—C8	−0.7 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2ⁱ	0.88	1.96	2.814 (2)	164
C12—H12···O2ⁱⁱ	0.95	2.52	3.435 (2)	163
C18—H18···O2ⁱⁱ	0.95	2.44	3.389 (3)	178

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

Acknowledgements

X-ray data were collected at the EPSRC X-ray Crystallographic Service, University of Southampton, England. JC and JT thanks the Consejería de Innovación, Ciencia y Empresa (Junta de Andalucía, Spain) and the Universidad de Jaén for financial support. JT also thanks the Universidad de Jaén for a research scholarship supporting a short stay at the EPSRC X-ray Crystallographic Service, University of Southampton, England. SC thanks UDENAR (Universidad de Narinõ, Colombia) for financial support.

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