organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

N-(2,4,6-Tri­methyl­phen­yl)formamide

aDepartment of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
*Correspondence e-mail: dave.liles@up.ac.za

(Received 6 December 2010; accepted 8 December 2010; online 11 December 2010)

The title compound, C10H13NO, was obtained as the unexpected, almost exclusive, product in the attempted synthesis of a manganese(I)–N-heterocyclic carbene (NHC) complex. The dihedral angle between the planes of the formamide moiety and the aryl ring is 68.06 (10)°. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds, forming infinite chains along the c axis.

Related literature

For background to formamide formation from NHCs, see: Denk et al. (2001[Denk, M. K., Rodenzo, J. M., Gupta, S. & Lough, A. (2001). J. Organomet. Chem. 617-618, 242-253.]). The rotation of the formamide entity out of the plane of the aryl ring and the hydrogen-bonding motif displayed by this structure are similar to those observed for the related compound N-(2,6-dimeth­yl)-formamide, see: Hanson et al. (2004[Hanson, J. R., Hitchcock, P. B. & Rodriguez-Medina, I. C. (2004). J. Chem. Res. pp. 664-666.]); Omondi et al. (2005[Omondi, B., Fernandes, M. A., Layh, M., Levendis, D. C., Look, J. L. & Mkwizu, T. S. P. (2005). CrystEngComm, 7, 690-700.]).

[Scheme 1]

Experimental

Crystal data
  • C10H13NO

  • Mr = 163.21

  • Monoclinic, P 21 /c

  • a = 8.0659 (7) Å

  • b = 15.9004 (13) Å

  • c = 8.4290 (7) Å

  • β = 119.361 (1)°

  • V = 942.17 (14) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.07 mm−1

  • T = 293 K

  • 0.44 × 0.38 × 0.28 mm

Data collection
  • Bruker (Siemens) P4 diffractometer fitted with a SMART 1K CCD detector

  • Absorption correction: multi-scan (SADABS; Bruker, 2001[Bruker (2001). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.946, Tmax = 0.979

  • 4988 measured reflections

  • 1778 independent reflections

  • 1607 reflections with I > 2σ(I)

  • Rint = 0.026

Refinement
  • R[F2 > 2σ(F2)] = 0.048

  • wR(F2) = 0.138

  • S = 1.09

  • 1778 reflections

  • 161 parameters

  • All H-atom parameters refined

  • Δρmax = 0.21 e Å−3

  • Δρmin = −0.21 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1⋯O1i 0.83 (2) 2.05 (2) 2.8775 (18) 171.4 (19)
Symmetry code: (i) [x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}].

Data collection: SMART (Bruker, 2001[Bruker (2001). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2001[Bruker (2001). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL and SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: POV-RAY (Cason, 2004[Cason, C. J. (2004). POV-RAY for Windows. Persistence of Vision, Raytracer Pty. Ltd, Victoria, Australia. URL: http://www.povray.org.]) and Mercury (Bruno et al., 2002[Bruno, I. J., Cole, J. C., Edgington, P. R., Kessler, M., Macrae, C. F., McCabe, P., Pearson, J. & Taylor, R. (2002). Acta Cryst. B58, 389-397.]); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

N-(2,4,6-Trimethyl-phenyl)-formamide (N-mesityl-formamide) (1) was formed as an unexpected product in the attempted synthesis of a manganese(I)—N-heterocyclic carbene (NHC) complex. Instead of the target complex, the mesityl formamide was obtained almost exclusively. The ylidene molecule, formed by deprotonation of 1,3-bis(2,4,6-trimethyl-phenyl)-imidazolium chloride (IMesHCl) by a strong base, is prone to undergo side reactions. Thus the strong base, and the subsequent addition of Mn(CO)5Br, resulted in the formation of N,N'-bis-mesityl-N-vinyl-formamidine and after hydrolysis of this molecule the NC—N bond dissociated to form 1 and a mesityl-vinyl-amine fragment which was not isolated. Denk et al. (2001) have reported the hydrolysis of NHCs, with formamide formation via ring opening, resulting in an acyclic product.

The molecular structure of the title compound (1) (Fig. 1) is similar to that of the related compound, N-(2,6-dimethyl-phenyl)-formamide, the structure of which has been reported at 173 K (Hanson, et al., 2004) and 293 K (Omondi, et al., 2005). Owing to the influence of the bulky methyl substituents in the 2 and 6 positions, the formamide moiety is rotated out of the plane of the aryl ring: in 1, the angle between the planes of the formamide moiety (C1, N1, C10, O1) and the aryl ring is 68.06 (10)°. This compares with 64.75 (12)° (173 K) and 66.45 (12)° (293 K) found for the 2,6-dimethyl analogue.

In the formamide moieties of both structures the O atom is trans to N—H thus allowing the molecules to be linked to form infinite chains by N—H···O hydrogen bonds. However the spatial arrangements within the chains differ. In the 2,6-dimethyl analogue (space group P212121), the axis of each chain is parallel to the a unit cell axis and neighbouring molecules within a chain are related by the a-axial unit cell translation. Thus the aryl ring of each molecule is parallel to those of its neighbours within the chain and they are stacked one above the other but with a step-wise offset. In contrast, in 1, the axis of each chain is parallel to the c unit cell axis and neighbouring molecules within a chain are related by a c-glide plane. Thus neighbouring molecules in a chain are arranged on opposite sides of the chain axis and the aryl rings are not mutually parallel (Fig. 2).

Related literature top

For background to formamide formation from NHCs, see: Denk et al. (2001). The rotation of the formamide entity out of the plane of the aryl ring and the hydrogen-bonding motif displayed by this structure are similar to those observed for the related compound N-(2,6-dimethyl)-formamide, see: Hanson et al. (2004); Omondi et al. (2005).

Experimental top

Mn(CO)5Br (3 mmol, 0.74 g) and Me3NO (2.8 mmol, 0.21 g) were stirred in thf resulting in a red solution. IMesHCl (3 mmol, 1.02 g) was deprotonated in thf by the addition of base (3 mmol) and the ylidene was added to the solution and stirred overnight. The thf solvent was removed and the products were separated on an aluminium oxide 90 (alox) column. Elution with dichloromethane (dcm) and thf yielded starting material and a yellow fraction respectively. The yellow fraction was crystallized from a saturated chloroform solution to give an unexpected organic product, N-mesityl-formamide (1, C10H13NO). 1H NMR (δ, p.p.m.), C6D6: 2.24 (br, 9H), 3.85 (br, 1H), 6.65 (br, 2H), 8.32 (br, 1H); 13C NMR (δ, p.p.m.), C6D6: 18.8, 21.2, 129.2, 130.2, 135.3, 137.6, 208.6.

Refinement top

The coordinates and individual Uiso parameters for all H atoms were freely refined.

Structure description top

N-(2,4,6-Trimethyl-phenyl)-formamide (N-mesityl-formamide) (1) was formed as an unexpected product in the attempted synthesis of a manganese(I)—N-heterocyclic carbene (NHC) complex. Instead of the target complex, the mesityl formamide was obtained almost exclusively. The ylidene molecule, formed by deprotonation of 1,3-bis(2,4,6-trimethyl-phenyl)-imidazolium chloride (IMesHCl) by a strong base, is prone to undergo side reactions. Thus the strong base, and the subsequent addition of Mn(CO)5Br, resulted in the formation of N,N'-bis-mesityl-N-vinyl-formamidine and after hydrolysis of this molecule the NC—N bond dissociated to form 1 and a mesityl-vinyl-amine fragment which was not isolated. Denk et al. (2001) have reported the hydrolysis of NHCs, with formamide formation via ring opening, resulting in an acyclic product.

The molecular structure of the title compound (1) (Fig. 1) is similar to that of the related compound, N-(2,6-dimethyl-phenyl)-formamide, the structure of which has been reported at 173 K (Hanson, et al., 2004) and 293 K (Omondi, et al., 2005). Owing to the influence of the bulky methyl substituents in the 2 and 6 positions, the formamide moiety is rotated out of the plane of the aryl ring: in 1, the angle between the planes of the formamide moiety (C1, N1, C10, O1) and the aryl ring is 68.06 (10)°. This compares with 64.75 (12)° (173 K) and 66.45 (12)° (293 K) found for the 2,6-dimethyl analogue.

In the formamide moieties of both structures the O atom is trans to N—H thus allowing the molecules to be linked to form infinite chains by N—H···O hydrogen bonds. However the spatial arrangements within the chains differ. In the 2,6-dimethyl analogue (space group P212121), the axis of each chain is parallel to the a unit cell axis and neighbouring molecules within a chain are related by the a-axial unit cell translation. Thus the aryl ring of each molecule is parallel to those of its neighbours within the chain and they are stacked one above the other but with a step-wise offset. In contrast, in 1, the axis of each chain is parallel to the c unit cell axis and neighbouring molecules within a chain are related by a c-glide plane. Thus neighbouring molecules in a chain are arranged on opposite sides of the chain axis and the aryl rings are not mutually parallel (Fig. 2).

For background to formamide formation from NHCs, see: Denk et al. (2001). The rotation of the formamide entity out of the plane of the aryl ring and the hydrogen-bonding motif displayed by this structure are similar to those observed for the related compound N-(2,6-dimethyl)-formamide, see: Hanson et al. (2004); Omondi et al. (2005).

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008) and SHELXL97 (Sheldrick, 2008); molecular graphics: POV-RAY (Cason, 2004) and Mercury (Bruno et al., 2002); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of 1 showing the atomic numbering scheme. Displacement ellipsoids are shown at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.
[Figure 2] Fig. 2. Packing diagram of 1 viewed approximately down the a-axis and showing O—H···O hydrogen bonding interactions which link molecules to form infinite chains.
N-(2,4,6-Trimethylphenyl)formamide top
Crystal data top
C10H13NOF(000) = 352
Mr = 163.21Dx = 1.151 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3714 reflections
a = 8.0659 (7) Åθ = 2.8–26.4°
b = 15.9004 (13) ŵ = 0.07 mm1
c = 8.4290 (7) ÅT = 293 K
β = 119.361 (1)°Prism, colourless
V = 942.17 (14) Å30.44 × 0.38 × 0.28 mm
Z = 4
Data collection top
Bruker P4
diffractometer
1778 independent reflections
Radiation source: fine-focus sealed tube1607 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.026
Detector resolution: 8.3 pixels mm-1θmax = 26.4°, θmin = 2.6°
φ and ω scansh = 910
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
k = 1418
Tmin = 0.946, Tmax = 0.979l = 105
4988 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.048Hydrogen site location: difference Fourier map
wR(F2) = 0.138All H-atom parameters refined
S = 1.09 w = 1/[σ2(Fo2) + (0.0738P)2 + 0.186P]
where P = (Fo2 + 2Fc2)/3
1778 reflections(Δ/σ)max = 0.004
161 parametersΔρmax = 0.21 e Å3
0 restraintsΔρmin = 0.21 e Å3
0 constraints
Crystal data top
C10H13NOV = 942.17 (14) Å3
Mr = 163.21Z = 4
Monoclinic, P21/cMo Kα radiation
a = 8.0659 (7) ŵ = 0.07 mm1
b = 15.9004 (13) ÅT = 293 K
c = 8.4290 (7) Å0.44 × 0.38 × 0.28 mm
β = 119.361 (1)°
Data collection top
Bruker P4
diffractometer
1778 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
1607 reflections with I > 2σ(I)
Tmin = 0.946, Tmax = 0.979Rint = 0.026
4988 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0480 restraints
wR(F2) = 0.138All H-atom parameters refined
S = 1.09Δρmax = 0.21 e Å3
1778 reflectionsΔρmin = 0.21 e Å3
161 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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
xyzUiso*/Ueq
C10.7933 (2)0.16285 (9)0.08870 (17)0.0407 (4)
C20.6198 (2)0.16921 (10)0.08652 (19)0.0466 (4)
C30.5674 (2)0.10396 (11)0.1617 (2)0.0509 (4)
H30.451 (3)0.1097 (13)0.161 (3)0.072 (6)*
C40.6785 (2)0.03318 (10)0.2356 (2)0.0488 (4)
C50.8489 (2)0.02819 (9)0.2331 (2)0.0466 (4)
H50.934 (3)0.0186 (12)0.288 (2)0.055 (5)*
C60.9094 (2)0.09227 (9)0.16142 (18)0.0421 (4)
C70.4899 (3)0.24369 (15)0.0026 (3)0.0701 (5)
H7A0.369 (5)0.236 (2)0.009 (5)0.139 (12)*
H7B0.479 (4)0.2576 (19)0.111 (5)0.115 (9)*
H7C0.530 (4)0.292 (2)0.078 (4)0.111 (9)*
C80.6158 (4)0.03631 (15)0.3157 (3)0.0718 (6)
H8A0.481 (5)0.056 (2)0.237 (5)0.132 (11)*
H8B0.694 (6)0.085 (3)0.348 (5)0.152 (13)*
H8C0.611 (4)0.0151 (19)0.415 (5)0.116 (9)*
C91.0959 (2)0.08575 (13)0.1626 (3)0.0571 (4)
H9A1.083 (3)0.0893 (13)0.040 (3)0.073 (6)*
H9B1.161 (4)0.0329 (16)0.214 (3)0.088 (7)*
H9C1.179 (3)0.1299 (15)0.234 (3)0.078 (6)*
N10.85323 (19)0.22763 (8)0.01026 (18)0.0489 (4)
H10.868 (3)0.2161 (12)0.078 (3)0.060 (5)*
C100.9063 (3)0.30398 (11)0.0798 (2)0.0579 (5)
H100.947 (2)0.3419 (11)0.007 (2)0.056 (5)*
O10.9086 (2)0.33069 (8)0.21640 (18)0.0792 (5)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0488 (8)0.0413 (7)0.0360 (7)0.0034 (6)0.0240 (6)0.0044 (5)
C20.0491 (8)0.0497 (8)0.0436 (8)0.0045 (6)0.0247 (6)0.0013 (6)
C30.0446 (8)0.0618 (10)0.0526 (8)0.0046 (7)0.0287 (7)0.0060 (7)
C40.0568 (9)0.0480 (8)0.0452 (8)0.0113 (7)0.0277 (7)0.0062 (6)
C50.0549 (9)0.0397 (8)0.0463 (8)0.0015 (6)0.0256 (7)0.0010 (6)
C60.0443 (7)0.0450 (8)0.0387 (7)0.0013 (6)0.0218 (6)0.0057 (5)
C70.0683 (12)0.0706 (13)0.0771 (13)0.0254 (10)0.0400 (10)0.0154 (11)
C80.0884 (15)0.0662 (13)0.0719 (12)0.0216 (11)0.0480 (12)0.0007 (10)
C90.0499 (9)0.0671 (11)0.0600 (10)0.0033 (8)0.0313 (8)0.0011 (8)
N10.0682 (8)0.0471 (7)0.0426 (7)0.0035 (6)0.0359 (6)0.0011 (5)
C100.0854 (12)0.0489 (9)0.0507 (8)0.0124 (8)0.0422 (9)0.0005 (7)
O10.1406 (13)0.0553 (8)0.0656 (8)0.0296 (8)0.0691 (9)0.0155 (6)
Geometric parameters (Å, º) top
C1—C21.394 (2)C7—H7B0.95 (3)
C1—C61.396 (2)C7—H7C0.95 (3)
C1—N11.4303 (18)C8—H8A1.00 (4)
C2—C31.385 (2)C8—H8B0.95 (4)
C2—C71.508 (2)C8—H8C0.92 (3)
C3—C41.382 (2)C9—H9A0.99 (2)
C3—H30.94 (2)C9—H9B0.97 (3)
C4—C51.387 (2)C9—H9C0.95 (2)
C4—C81.506 (2)N1—C101.325 (2)
C5—C61.390 (2)N1—H10.83 (2)
C5—H50.96 (2)C10—O11.219 (2)
C6—C91.503 (2)C10—H101.023 (18)
C7—H7A0.94 (4)
C2—C1—C6121.16 (13)C2—C7—H7C113.3 (18)
C2—C1—N1120.43 (13)H7A—C7—H7C100 (3)
C6—C1—N1118.38 (13)H7B—C7—H7C109 (3)
C3—C2—C1117.98 (14)C4—C8—H8A114.8 (19)
C3—C2—C7120.32 (16)C4—C8—H8B114 (2)
C1—C2—C7121.70 (15)H8A—C8—H8B107 (3)
C4—C3—C2122.68 (14)C4—C8—H8C108.2 (19)
C4—C3—H3120.4 (13)H8A—C8—H8C101 (3)
C2—C3—H3117.0 (13)H8B—C8—H8C111 (3)
C3—C4—C5117.91 (14)C6—C9—H9A113.2 (12)
C3—C4—C8120.91 (16)C6—C9—H9B112.6 (14)
C5—C4—C8121.18 (16)H9A—C9—H9B105.7 (19)
C4—C5—C6121.78 (14)C6—C9—H9C110.0 (13)
C4—C5—H5121.0 (11)H9A—C9—H9C107.6 (18)
C6—C5—H5117.1 (11)H9B—C9—H9C107.3 (19)
C5—C6—C1118.48 (13)C10—N1—C1124.38 (12)
C5—C6—C9120.70 (14)C10—N1—H1116.2 (13)
C1—C6—C9120.83 (14)C1—N1—H1119.1 (13)
C2—C7—H7A113 (2)O1—C10—N1126.09 (15)
C2—C7—H7B110.9 (19)O1—C10—H10120.0 (10)
H7A—C7—H7B111 (3)N1—C10—H10113.9 (10)
C6—C1—C2—C31.1 (2)C4—C5—C6—C10.7 (2)
N1—C1—C2—C3178.93 (13)C4—C5—C6—C9179.23 (14)
C6—C1—C2—C7177.86 (16)C2—C1—C6—C50.4 (2)
N1—C1—C2—C70.0 (2)N1—C1—C6—C5178.22 (12)
C1—C2—C3—C40.9 (2)C2—C1—C6—C9179.75 (14)
C7—C2—C3—C4178.09 (16)N1—C1—C6—C91.9 (2)
C2—C3—C4—C50.1 (2)C2—C1—N1—C1070.1 (2)
C2—C3—C4—C8179.94 (16)C6—C1—N1—C10112.01 (18)
C3—C4—C5—C60.9 (2)C1—N1—C10—O11.5 (3)
C8—C4—C5—C6179.26 (15)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.83 (2)2.05 (2)2.8775 (18)171.4 (19)
Symmetry code: (i) x, y+1/2, z1/2.

Experimental details

Crystal data
Chemical formulaC10H13NO
Mr163.21
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)8.0659 (7), 15.9004 (13), 8.4290 (7)
β (°) 119.361 (1)
V3)942.17 (14)
Z4
Radiation typeMo Kα
µ (mm1)0.07
Crystal size (mm)0.44 × 0.38 × 0.28
Data collection
DiffractometerBruker P4
Absorption correctionMulti-scan
(SADABS; Bruker, 2001)
Tmin, Tmax0.946, 0.979
No. of measured, independent and
observed [I > 2σ(I)] reflections
4988, 1778, 1607
Rint0.026
(sin θ/λ)max1)0.626
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.138, 1.09
No. of reflections1778
No. of parameters161
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.21, 0.21

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXTL (Sheldrick, 2008) and SHELXL97 (Sheldrick, 2008), POV-RAY (Cason, 2004) and Mercury (Bruno et al., 2002), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.83 (2)2.05 (2)2.8775 (18)171.4 (19)
Symmetry code: (i) x, y+1/2, z1/2.
 

Acknowledgements

Funding received for this work from the University of Pretoria, and the National Research Foundation is acknowledged.

References

First citationBruker (2001). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationBruno, I. J., Cole, J. C., Edgington, P. R., Kessler, M., Macrae, C. F., McCabe, P., Pearson, J. & Taylor, R. (2002). Acta Cryst. B58, 389–397.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationCason, C. J. (2004). POV-RAY for Windows. Persistence of Vision, Raytracer Pty. Ltd, Victoria, Australia. URL: http://www.povray.org.  Google Scholar
First citationDenk, M. K., Rodenzo, J. M., Gupta, S. & Lough, A. (2001). J. Organomet. Chem. 617–618, 242–253.  Web of Science CSD CrossRef CAS Google Scholar
First citationHanson, J. R., Hitchcock, P. B. & Rodriguez-Medina, I. C. (2004). J. Chem. Res. pp. 664–666.  CrossRef Google Scholar
First citationOmondi, B., Fernandes, M. A., Layh, M., Levendis, D. C., Look, J. L. & Mkwizu, T. S. P. (2005). CrystEngComm, 7, 690–700.  Web of Science CSD CrossRef CAS Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS 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.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds