N,N′-(4,5-Dimethyl-1,2-phenyl­ene)bis­(pyridine-2-carboxamide)

Van der Berg, P.C.W.; Visser, H.G.; Roodt, A.; Muller, T.J.

doi:10.1107/S1600536812035064

organic compounds

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ISSN: 2056-9890

Volume 68| Part 9| September 2012| Page o2739

doi:10.1107/S1600536812035064

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N,N′-(4,5-Dimethyl-1,2-phenylene)bis(pyridine-2-carboxamide)

Phillipus C. W. Van der Berg,^a ^* Hendrik G. Visser,^a Andreas Roodt ^a and Theunis J. Muller ^a

^aDepartment of Chemistry, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa
^*Correspondence e-mail: vanderbergpcw@ufs.ac.za

(Received 31 July 2012; accepted 8 August 2012; online 23 August 2012)

In the title compound, C₂₀H₁₈N₄O₂, the dihedral angles between the central benzene ring and the pyridine rings are 57.55 (6) and 22.05 (8)°. The molecular conformation is stabilized by intramolecular N—H⋯N interactions and in the crystal structure an intermolecular asymmetric cyclic hydrogen-bonding association involving both amide N—H donors and a common amide O-atom acceptor gives a chain extending along the c axis.

Related literature

For related structures, see: Jain et al. (2004 ); Lin et al. (2001 ); Roodt et al. (2011 ); Schutte et al. (2011 ); Van der Berg et al. (2011 ).

Experimental

Crystal data

C₂₀H₁₈N₄O₂
M_r = 346.38
Monoclinic, C c
a = 12.1299 (8) Å
b = 18.9418 (8) Å
c = 7.7549 (4) Å
β = 100.375 (4)°
V = 1752.65 (17) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100 K
0.78 × 0.08 × 0.07 mm

Data collection

Bruker X8 APEXII KappaCCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004 ) T_min = 0.990, T_max = 0.994
15674 measured reflections
3860 independent reflections
3529 reflections with I > 2σ(I)
R_int = 0.031

Refinement

R[F² > 2σ(F²)] = 0.036
wR(F²) = 0.090
S = 1.04
3860 reflections
237 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2′⋯N1	0.86 (2)	2.20 (2)	2.6698 (19)	114.2 (16)
N2—H2′⋯N3	0.86 (2)	2.48 (2)	2.777 (2)	101.2 (15)
N2—H2′⋯O2ⁱ	0.86 (2)	2.60 (2)	3.2112 (19)	129.0 (17)
N3—H3′⋯O2ⁱ	0.86 (2)	2.05 (2)	2.8508 (19)	155.5 (18)
N3—H3′⋯N4	0.86 (2)	2.28 (2)	2.6670 (19)	107.8 (15)
Symmetry code: (i) $[x, -y+1, z-{\script{1\over 2}}]$ .

Data collection: APEX2 (Bruker, 2010 ); cell refinement: SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536812035064/zs2225sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812035064/zs2225Isup2.hkl

checkCIF report

Comment top

The title compound C₂₀H₁₈N₄O₂ was synthesized as a ligand for potential use in medical and radiopharmaceutical applications. In this compound, which has one molecule in the asymmetric unit (Fig. 1), the dihedral angles between the central benzene ring and the pyridine rings are 57.55 (6) and 22.05 (8)°. The molecular conformation is stabilized by intramolecular N—H···N interactions and in the crystal structure an intermolecular asymmetric cyclic hydrogen-bonding association involving both amide N—H donors and a common amide O-atom acceptor (O2ⁱ) (Table 1), give a one-dimensional chain extending along c. The related structures from Roodt et al. (2011) and Schutte et al. (2011) also contribute to our studies in radiopharmaceutical design and reactivity.

Related literature top

For related structures, see: Jain et al. (2004); Lin et al. (2001); Roodt et al. (2011); Schutte et al. (2011); Van der Berg et al. (2011).

Experimental top

Under oxygen atmosphere, picolinic acid (5.73 g, 0.0465 mol) was added as a solid in one portion to a suspension of 4,5-dimethyl-1,2-phenylenediamine (3.00 g, 0.0220 mol) in pyridine (20 ml) and the mixture was stirred at 40 °C for 40 min. Triphenylphosphite (30 ml) was added dropwise over 10 minutes after which the temperature was increased to 90–100 °C and stirred for a further 24 h. On cooling the precipitate was filtered, washed with H₂O (50 ml) and then MeOH (50 ml). The precipitate was recrystallized in chloroform to giving colourless crystals after five days

Computing details top

Data collection: APEX2 (Bruker, 2010); cell refinement: SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

Figure 1. Molecular structure of the title compound, showing the atom numbering scheme, with displacement ellipsoids drawn at the 50% probability level.

N,N'-(4,5-Dimethyl-1,2-phenylene)bis(pyridine-2-carboxamide) top

Crystal data top

C₂₀H₁₈N₄O₂	F(000) = 728
M_r = 346.38	D_x = 1.313 Mg m⁻³
Monoclinic, Cc	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C -2yc	Cell parameters from 5487 reflections
a = 12.1299 (8) Å	θ = 3.1–28.3°
b = 18.9418 (8) Å	µ = 0.09 mm⁻¹
c = 7.7549 (4) Å	T = 100 K
β = 100.375 (4)°	Needle, colourless
V = 1752.65 (17) Å³	0.78 × 0.08 × 0.07 mm
Z = 4

Data collection top

Bruker X8 APEXII KappaCCD diffractometer	3860 independent reflections
Radiation source: sealed tube	3529 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.031
ϕ and ω scans	θ_max = 28°, θ_min = 3.1°
Absorption correction: multi-scan (SADABS; Bruker, 2004)	h = −16→16
T_min = 0.990, T_max = 0.994	k = −24→24
15674 measured reflections	l = −10→10

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)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.090	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ²(F_o²) + (0.0456P)² + 0.7043P] where P = (F_o² + 2F_c²)/3
3860 reflections	(Δ/σ)_max = 0.001
237 parameters	Δρ_max = 0.26 e Å⁻³
2 restraints	Δρ_min = −0.20 e Å⁻³

Crystal data top

C₂₀H₁₈N₄O₂	V = 1752.65 (17) Å³
M_r = 346.38	Z = 4
Monoclinic, Cc	Mo Kα radiation
a = 12.1299 (8) Å	µ = 0.09 mm⁻¹
b = 18.9418 (8) Å	T = 100 K
c = 7.7549 (4) Å	0.78 × 0.08 × 0.07 mm
β = 100.375 (4)°

Data collection top

Bruker X8 APEXII KappaCCD diffractometer	3860 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2004)	3529 reflections with I > 2σ(I)
T_min = 0.990, T_max = 0.994	R_int = 0.031
15674 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.036	2 restraints
wR(F²) = 0.090	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	Δρ_max = 0.26 e Å⁻³
3860 reflections	Δρ_min = −0.20 e Å⁻³
237 parameters

Special details top

Experimental. The intensity data was collected on a Bruker X8 ApexII 4 K Kappa CCD diffractometer using an exposure time of 30 s/frame. A total of 1895 frames was collected with a frame width of 0.5° covering up to θ = 28.29° with 99.9% completeness accomplished.

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

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > 2σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
C6	0.77131 (13)	0.70520 (9)	0.3849 (2)	0.0204 (3)
C10	0.34827 (15)	0.64314 (11)	0.4195 (3)	0.0336 (4)
H10A	0.2857	0.6104	0.4193	0.050*	0.5
H10B	0.3246	0.6815	0.3361	0.050*	0.5
H10C	0.3713	0.6629	0.5373	0.050*	0.5
H10D	0.3688	0.6927	0.4424	0.050*	0.5
H10E	0.3298	0.6217	0.5257	0.050*	0.5
H10F	0.2831	0.6403	0.3245	0.050*	0.5
C11	0.33503 (15)	0.48994 (11)	0.3373 (3)	0.0313 (4)
H11A	0.3459	0.4411	0.3025	0.047*	0.5
H11B	0.2703	0.5102	0.2592	0.047*	0.5
H11C	0.3218	0.4908	0.4583	0.047*	0.5
H11D	0.2794	0.5204	0.3775	0.047*	0.5
H11E	0.355	0.4512	0.4208	0.047*	0.5
H11F	0.3035	0.4706	0.2217	0.047*	0.5
C15	0.77150 (13)	0.44582 (8)	0.2917 (2)	0.0202 (2)
N2	0.73461 (11)	0.64533 (7)	0.2985 (2)	0.0221 (3)
N3	0.72056 (11)	0.50299 (7)	0.21172 (19)	0.0190 (3)
O1	0.72183 (10)	0.73844 (7)	0.48200 (17)	0.0277 (3)
O2	0.74071 (9)	0.41395 (6)	0.41242 (15)	0.0202 (2)
H2'	0.7803 (17)	0.6283 (10)	0.237 (3)	0.027 (5)*
H3'	0.7438 (16)	0.5199 (10)	0.122 (3)	0.024 (5)*
C1	1.03548 (14)	0.71236 (10)	0.2222 (2)	0.0283 (4)
H1	1.0731	0.6853	0.1474	0.034*
C2	1.08852 (15)	0.77174 (10)	0.3009 (2)	0.0293 (4)
H2	1.1603	0.7852	0.2795	0.035*
C3	1.03552 (16)	0.81103 (10)	0.4107 (2)	0.0289 (4)
H3	1.07	0.8521	0.4668	0.035*
C4	0.93064 (15)	0.78956 (9)	0.4380 (2)	0.0249 (4)
H4	0.8918	0.8154	0.5134	0.03*
C5	0.88403 (13)	0.72965 (9)	0.3529 (2)	0.0197 (3)
C7	0.63512 (12)	0.60847 (8)	0.3093 (2)	0.0192 (3)
C8	0.54288 (15)	0.64111 (9)	0.3586 (2)	0.0241 (3)
H8	0.5468	0.6899	0.3874	0.029*
C9	0.44549 (13)	0.60415 (9)	0.3667 (2)	0.0243 (4)
C12	0.43827 (14)	0.53253 (9)	0.3249 (2)	0.0235 (3)
C13	0.53017 (14)	0.50011 (9)	0.2728 (2)	0.0215 (3)
H13	0.5258	0.4515	0.2421	0.026*
C14	0.62761 (12)	0.53699 (8)	0.2646 (2)	0.0189 (3)
C16	0.87530 (13)	0.42368 (9)	0.2250 (2)	0.0189 (3)
C17	0.93911 (15)	0.36937 (9)	0.3085 (2)	0.0255 (4)
H17	0.9157	0.344	0.4012	0.031*
C18	1.03894 (15)	0.35268 (10)	0.2530 (3)	0.0295 (4)
H18	1.0859	0.316	0.3079	0.035*
C19	1.06792 (15)	0.39063 (10)	0.1168 (2)	0.0283 (4)
H19	1.1357	0.3806	0.0764	0.034*
C20	0.99767 (15)	0.44332 (10)	0.0395 (3)	0.0301 (4)
H20	1.0181	0.4685	−0.056	0.036*
N1	0.93415 (12)	0.69083 (8)	0.2456 (2)	0.0248 (3)
N4	0.90251 (12)	0.46069 (8)	0.09200 (19)	0.0245 (3)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C6	0.0205 (7)	0.0210 (8)	0.0200 (8)	0.0032 (6)	0.0050 (6)	0.0032 (6)
C10	0.0211 (8)	0.0387 (10)	0.0437 (12)	0.0041 (7)	0.0132 (8)	−0.0001 (9)
C11	0.0227 (8)	0.0378 (10)	0.0351 (10)	−0.0060 (7)	0.0102 (8)	−0.0020 (8)
C15	0.0209 (4)	0.0201 (5)	0.0205 (4)	−0.0022 (3)	0.0064 (4)	−0.0014 (4)
N2	0.0184 (7)	0.0206 (7)	0.0304 (8)	0.0008 (5)	0.0124 (6)	−0.0027 (6)
N3	0.0181 (6)	0.0214 (7)	0.0192 (7)	−0.0007 (5)	0.0081 (5)	0.0004 (6)
O1	0.0252 (6)	0.0322 (7)	0.0283 (7)	0.0007 (5)	0.0117 (5)	−0.0061 (6)
O2	0.0209 (4)	0.0201 (5)	0.0205 (4)	−0.0022 (3)	0.0064 (4)	−0.0014 (4)
C1	0.0238 (8)	0.0362 (10)	0.0265 (9)	−0.0018 (7)	0.0088 (7)	−0.0063 (8)
C2	0.0253 (9)	0.0384 (11)	0.0253 (9)	−0.0092 (7)	0.0078 (7)	0.0008 (8)
C3	0.0343 (10)	0.0279 (9)	0.0243 (9)	−0.0102 (7)	0.0043 (8)	−0.0031 (8)
C4	0.0291 (9)	0.0253 (8)	0.0215 (8)	−0.0022 (7)	0.0079 (7)	−0.0008 (7)
C5	0.0196 (7)	0.0191 (8)	0.0213 (8)	0.0005 (6)	0.0061 (6)	0.0034 (6)
C7	0.0168 (7)	0.0215 (8)	0.0202 (8)	−0.0008 (6)	0.0060 (6)	0.0027 (6)
C8	0.0212 (7)	0.0253 (8)	0.0268 (9)	0.0037 (7)	0.0072 (7)	0.0020 (7)
C9	0.0196 (8)	0.0314 (9)	0.0232 (8)	0.0047 (7)	0.0070 (7)	0.0027 (7)
C12	0.0174 (7)	0.0329 (9)	0.0205 (8)	−0.0024 (7)	0.0041 (6)	0.0035 (7)
C13	0.0217 (7)	0.0238 (8)	0.0196 (8)	−0.0022 (6)	0.0055 (6)	−0.0005 (6)
C14	0.0173 (7)	0.0240 (8)	0.0158 (8)	0.0020 (6)	0.0044 (6)	0.0014 (6)
C16	0.0188 (7)	0.0188 (7)	0.0190 (7)	−0.0015 (6)	0.0035 (6)	−0.0040 (6)
C17	0.0262 (8)	0.0248 (8)	0.0274 (9)	0.0022 (7)	0.0097 (7)	0.0020 (7)
C18	0.0271 (9)	0.0278 (9)	0.0346 (10)	0.0079 (7)	0.0079 (8)	0.0012 (8)
C19	0.0210 (8)	0.0356 (10)	0.0302 (9)	0.0049 (7)	0.0096 (7)	−0.0046 (8)
C20	0.0274 (9)	0.0375 (10)	0.0282 (9)	0.0030 (7)	0.0128 (8)	0.0046 (8)
N1	0.0218 (7)	0.0269 (7)	0.0275 (8)	−0.0029 (6)	0.0089 (6)	−0.0051 (6)
N4	0.0231 (7)	0.0290 (8)	0.0227 (7)	0.0031 (6)	0.0080 (6)	0.0027 (6)

Geometric parameters (Å, º) top

C6—O1	1.219 (2)	C1—H1	0.95
C6—N2	1.351 (2)	C2—C3	1.375 (3)
C6—C5	1.506 (2)	C2—H2	0.95
C10—C9	1.509 (2)	C3—C4	1.388 (2)
C10—H10A	0.98	C3—H3	0.95
C10—H10B	0.98	C4—C5	1.381 (2)
C10—H10C	0.98	C4—H4	0.95
C10—H10D	0.98	C5—N1	1.336 (2)
C10—H10E	0.98	C7—C8	1.391 (2)
C10—H10F	0.98	C7—C14	1.397 (2)
C11—C12	1.507 (2)	C8—C9	1.384 (2)
C11—H11A	0.98	C8—H8	0.95
C11—H11B	0.98	C9—C12	1.394 (2)
C11—H11C	0.98	C12—C13	1.395 (2)
C11—H11D	0.98	C13—C14	1.384 (2)
C11—H11E	0.98	C13—H13	0.95
C11—H11F	0.98	C16—N4	1.336 (2)
C15—O2	1.2274 (19)	C16—C17	1.377 (2)
C15—N3	1.342 (2)	C17—C18	1.392 (2)
C15—C16	1.505 (2)	C17—H17	0.95
N2—C7	1.410 (2)	C18—C19	1.374 (3)
N2—H2'	0.86 (2)	C18—H18	0.95
N3—C14	1.421 (2)	C19—C20	1.378 (3)
N3—H3'	0.86 (2)	C19—H19	0.95
C1—N1	1.338 (2)	C20—N4	1.333 (2)
C1—C2	1.382 (3)	C20—H20	0.95

O1—C6—N2	125.78 (16)	C15—N3—H3'	119.0 (13)
O1—C6—C5	120.35 (15)	C14—N3—H3'	117.3 (13)
N2—C6—C5	113.87 (14)	N1—C1—C2	123.65 (17)
C9—C10—H10A	109.5	N1—C1—H1	118.2
C9—C10—H10B	109.5	C2—C1—H1	118.2
H10A—C10—H10B	109.5	C3—C2—C1	118.80 (16)
C9—C10—H10C	109.5	C3—C2—H2	120.6
H10A—C10—H10C	109.5	C1—C2—H2	120.6
H10B—C10—H10C	109.5	C2—C3—C4	118.66 (16)
C9—C10—H10D	109.5	C2—C3—H3	120.7
H10A—C10—H10D	141.1	C4—C3—H3	120.7
H10B—C10—H10D	56.3	C5—C4—C3	118.40 (16)
H10C—C10—H10D	56.3	C5—C4—H4	120.8
C9—C10—H10E	109.5	C3—C4—H4	120.8
H10A—C10—H10E	56.3	N1—C5—C4	123.82 (14)
H10B—C10—H10E	141.1	N1—C5—C6	117.49 (14)
H10C—C10—H10E	56.3	C4—C5—C6	118.67 (15)
H10D—C10—H10E	109.5	C8—C7—C14	118.66 (14)
C9—C10—H10F	109.5	C8—C7—N2	122.39 (15)
H10A—C10—H10F	56.3	C14—C7—N2	118.93 (14)
H10B—C10—H10F	56.3	C9—C8—C7	121.53 (15)
H10C—C10—H10F	141.1	C9—C8—H8	119.2
H10D—C10—H10F	109.5	C7—C8—H8	119.2
H10E—C10—H10F	109.5	C8—C9—C12	120.01 (15)
C12—C11—H11A	109.5	C8—C9—C10	118.66 (16)
C12—C11—H11B	109.5	C12—C9—C10	121.33 (16)
H11A—C11—H11B	109.5	C9—C12—C13	118.41 (15)
C12—C11—H11C	109.5	C9—C12—C11	121.62 (16)
H11A—C11—H11C	109.5	C13—C12—C11	119.96 (16)
H11B—C11—H11C	109.5	C14—C13—C12	121.65 (15)
C12—C11—H11D	109.5	C14—C13—H13	119.2
H11A—C11—H11D	141.1	C12—C13—H13	119.2
H11B—C11—H11D	56.3	C13—C14—C7	119.73 (14)
H11C—C11—H11D	56.3	C13—C14—N3	120.85 (14)
C12—C11—H11E	109.5	C7—C14—N3	119.42 (13)
H11A—C11—H11E	56.3	N4—C16—C17	123.97 (15)
H11B—C11—H11E	141.1	N4—C16—C15	117.22 (14)
H11C—C11—H11E	56.3	C17—C16—C15	118.74 (14)
H11D—C11—H11E	109.5	C16—C17—C18	118.08 (16)
C12—C11—H11F	109.5	C16—C17—H17	121
H11A—C11—H11F	56.3	C18—C17—H17	121
H11B—C11—H11F	56.3	C19—C18—C17	118.40 (17)
H11C—C11—H11F	141.1	C19—C18—H18	120.8
H11D—C11—H11F	109.5	C17—C18—H18	120.8
H11E—C11—H11F	109.5	C18—C19—C20	119.32 (16)
O2—C15—N3	124.85 (15)	C18—C19—H19	120.3
O2—C15—C16	120.91 (14)	C20—C19—H19	120.3
N3—C15—C16	114.22 (14)	N4—C20—C19	123.20 (17)
C6—N2—C7	126.56 (14)	N4—C20—H20	118.4
C6—N2—H2'	113.8 (13)	C19—C20—H20	118.4
C7—N2—H2'	119.5 (13)	C5—N1—C1	116.67 (14)
C15—N3—C14	123.74 (14)	C20—N4—C16	117.01 (15)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2′···N1	0.86 (2)	2.20 (2)	2.6698 (19)	114.2 (16)
N2—H2′···N3	0.86 (2)	2.48 (2)	2.777 (2)	101.2 (15)
N2—H2′···O2ⁱ	0.86 (2)	2.60 (2)	3.2112 (19)	129.0 (17)
N3—H3′···O2ⁱ	0.86 (2)	2.05 (2)	2.8508 (19)	155.5 (18)
N3—H3′···N4	0.86 (2)	2.28 (2)	2.6670 (19)	107.8 (15)
C8—H8···O1	0.95	2.31	2.877 (2)	118
C2—H2···O1ⁱⁱ	0.95	2.59	3.195 (2)	122
C3—H3···O2ⁱⁱⁱ	0.95	2.48	3.160 (2)	128

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

Experimental details

Crystal data
Chemical formula	C₂₀H₁₈N₄O₂
M_r	346.38
Crystal system, space group	Monoclinic, Cc
Temperature (K)	100
a, b, c (Å)	12.1299 (8), 18.9418 (8), 7.7549 (4)
β (°)	100.375 (4)
V (Å³)	1752.65 (17)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.78 × 0.08 × 0.07

Data collection
Diffractometer	Bruker X8 APEXII KappaCCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2004)
T_min, T_max	0.990, 0.994
No. of measured, independent and observed [I > 2σ(I)] reflections	15674, 3860, 3529
R_int	0.031
(sin θ/λ)_max (Å⁻¹)	0.661

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.036, 0.090, 1.03
No. of reflections	3860
No. of parameters	237
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.26, −0.20

Computer programs: APEX2 (Bruker, 2010), SAINT-Plus (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg & Putz, 2005), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2'···N1	0.86 (2)	2.20 (2)	2.6698 (19)	114.2 (16)
N2—H2'···N3	0.86 (2)	2.48 (2)	2.777 (2)	101.2 (15)
N2—H2'···O2ⁱ	0.86 (2)	2.60 (2)	3.2112 (19)	129.0 (17)
N3—H3'···O2ⁱ	0.86 (2)	2.05 (2)	2.8508 (19)	155.5 (18)
N3—H3'···N4	0.86 (2)	2.28 (2)	2.6670 (19)	107.8 (15)

Symmetry code: (i) x, −y+1, z−1/2.

Acknowledgements

The authors would like to thank the Department of Chemistry of the University of the Free State, the NRF, NTeMBI, THRIP and Sasol Ltd for funding.

References

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