(Z)-Ethyl 3-(4-chloro­phen­yl)-2-cyano-3-(2,6-difluoro­benzamido)acrylate

Dehua, Z.; Xiaoyan, Z.

doi:10.1107/S1600536808034818

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 64| Part 12| December 2008| Page o2254

doi:10.1107/S1600536808034818

Open

access

(Z)-Ethyl 3-(4-chlorophenyl)-2-cyano-3-(2,6-difluorobenzamido)acrylate

Zhang Dehua ^a and Zhang Xiaoyan ^b ^*

^aDepartment of Chemistry and Environmental Engineering, Hubei Normal University, Huangshi 435002, People's Republic of China, and ^bSchool of Mathematics and Physics, Huangshi Institute of Tecnology, Huangshi 435003, People's Republic of China
^*Correspondence e-mail: zhangdehua200@163.com

(Received 16 September 2008; accepted 24 October 2008; online 8 November 2008)

The title compound, C₁₉H₁₃ClF₂N₂O₃, was prepared by the reaction of (Z)-ethyl 3-amino-3-(4-chlorophenyl)-2-cyanoacrylate and 2,6-difluorobenzoyl chloride. The dihedral angle between the chlorobenzene and fluorobenzene rings is 37.0 (1)°. The ethyl group is disordered over two positions [occupancies = 0.52 (2):0.48 (2)]. In addition to intramolecular N—H⋯O and N—H⋯F hydrogen bonds, the crystal packing shows the molecules to be connected by intermolecular C—H⋯O and C—H⋯N hydrogen bonds.

Related literature

The title compound is useful as an inhibitor of Pyricularia oryzae, Rhizoctonia solani, Botrytis cinerea and Gibberella zeae, see: Heller et al. (2004 ); Creagh & Hubbell (1992 ); Ibers & Hamilton (1964 ).

Experimental

Crystal data

C₁₉H₁₃ClF₂N₂O₃
M_r = 390.76
Triclinic, $[P \overline 1]$
a = 8.919 (5) Å
b = 9.7560 (6) Å
c = 11.2717 (7) Å
α = 91.9710 (10)°
β = 110.0940 (10)°
γ = 91.4490 (10)°
V = 919.9 (5) Å³
Z = 2
Mo Kα radiation
μ = 0.25 mm⁻¹
T = 298 (2) K
0.23 × 0.20 × 0.10 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: none
7196 measured reflections
3556 independent reflections
2524 reflections with I > 2σ(I)
R_int = 0.053

Refinement

R[F² > 2σ(F²)] = 0.052
wR(F²) = 0.154
S = 1.10
3556 reflections
265 parameters
6 restraints
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.31 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O2	0.86	2.05	2.674 (2)	129
N1—H1⋯F1	0.86	2.36	2.827 (2)	115
C18—H18B⋯O1ⁱ	0.97	2.58	2.990 (7)	106
C10—H10⋯N2ⁱⁱ	0.93	2.62	3.302 (3)	131
C5—H5⋯N2ⁱⁱⁱ	0.93	2.59	3.432 (3)	150
Symmetry codes: (i) x, y+1, z; (ii) -x, -y+2, -z+1; (iii) x+1, y, z+1.

Data collection: SMART (Bruker, 1998 ); cell refinement: SAINT (Bruker, 1999 ); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808034818/fl2223sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808034818/fl2223Isup2.hkl

checkCIF report

Comment top

Recently, 2-cyanoacrylates have been in widespread used as agrochemicals because of their unique mechanism of action and good environmental profiles. The title compound is useful as an inhibitor of Pyricularia oryzae, Rhizoctonia solani, Botrytis cinerea and Gibberella zeae (Heller et al., 2004; Creagh & Hubbell, 1992; Ibers & Hamilton, 1964).

In the title compound(Fig.1),all bond lengths and angles are unexceptional.The planar chlorobenzene ring is approximately perpendicular to the fluorobenzene ring with a dihedral angle of 37.0 (1)°. The ethyl group is disordered over two positions occupancies (0.52 (2):0.48 (2)).The molecular conformation is stabilized by C—H···O and N—H···O hydrogen bonds (Table 1). The crystal packing is governed by additional N—H···O and N—H···F Interactions (Fig. 2).

Related literature top

For background information see: Heller et al. (2004); Creagh & Hubbell (1992); Ibers & Hamilton (1964).

Experimental top

To a solution of (Z)-ethyl 3-amino-3-(4-chlorophenyl)-2-cyanoacrylate (1.25 g,0.0050 mol) in CH₂Cl₂(18 ml), 2,6-difluorobenzoyl chloride (2.65 g,0.015 mol) was added. Subsequently, Et₃N(1.52 g,0.015 mol) waa dropped into the solution under stirring. Then, the reaction mixture was heated to reflux and stirred for 4 h and then cooled to room temperature. The reaction solution was filtered off and some white solid was separated. The organic phase was washed with water and then dried over Na₂SO₄. After removal of the solvent, a brown dope was obtained. After column chromatography using ethylacetate/light petroleum (1:6) as the eluent. Small single crystals were grown from a solution of ethyl acetate/petroleum ether(3:1) after 45 days,at room temperature.

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SMART (Bruker, 1998); data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of the title compound, showing 30% probability displacement ellipsoids and the atom-numbering scheme.
	Fig. 2. The packing of the title compound, viewed down the c axis.

(Z)-Ethyl 3-(4-chlorophenyl)-2-cyano-3-(2,6-difluorobenzamido)acrylate top

Crystal data top

C₁₉H₁₃ClF₂N₂O₃	Z = 2
M_r = 390.76	F(000) = 400
Triclinic, P1	D_x = 1.411 Mg m⁻³
a = 8.919 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.7560 (6) Å	Cell parameters from 2672 reflections
c = 11.2717 (7) Å	θ = 2.4–26.8°
α = 91.971 (1)°	µ = 0.25 mm⁻¹
β = 110.094 (1)°	T = 298 K
γ = 91.449 (1)°	Block, colorless
V = 919.9 (5) Å³	0.23 × 0.20 × 0.10 mm

Data collection top

Bruker SMART CCD area-detector diffractometer	2524 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.053
Graphite monochromator	θ_max = 26.0°, θ_min = 1.9°
ϕ and ω scans	h = −10→9
7196 measured reflections	k = −12→12
3556 independent reflections	l = −10→13

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)] = 0.052	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.154	H-atom parameters constrained
S = 1.10	w = 1/[σ²(F_o²) + (0.0794P)² + 0.0184P] where P = (F_o² + 2F_c²)/3
3556 reflections	(Δ/σ)_max < 0.001
265 parameters	Δρ_max = 0.22 e Å⁻³
6 restraints	Δρ_min = −0.31 e Å⁻³

Crystal data top

C₁₉H₁₃ClF₂N₂O₃	γ = 91.449 (1)°
M_r = 390.76	V = 919.9 (5) Å³
Triclinic, P1	Z = 2
a = 8.919 (5) Å	Mo Kα radiation
b = 9.7560 (6) Å	µ = 0.25 mm⁻¹
c = 11.2717 (7) Å	T = 298 K
α = 91.971 (1)°	0.23 × 0.20 × 0.10 mm
β = 110.094 (1)°

Data collection top

Bruker SMART CCD area-detector diffractometer	2524 reflections with I > 2σ(I)
7196 measured reflections	R_int = 0.053
3556 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.052	6 restraints
wR(F²) = 0.154	H-atom parameters constrained
S = 1.10	Δρ_max = 0.22 e Å⁻³
3556 reflections	Δρ_min = −0.31 e Å⁻³
265 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 > σ(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)
C1	0.7937 (2)	0.8595 (2)	0.98955 (19)	0.0535 (5)
C2	0.9102 (3)	0.7653 (3)	1.0005 (2)	0.0732 (7)
C3	1.0531 (3)	0.7682 (3)	1.0992 (3)	0.0838 (8)
H3	1.1291	0.7036	1.1024	0.101*
C4	1.0803 (3)	0.8678 (3)	1.1917 (3)	0.0803 (8)
H4	1.1756	0.8699	1.2601	0.096*
C5	0.9711 (3)	0.9653 (3)	1.1869 (2)	0.0751 (7)
H5	0.9911	1.0336	1.2506	0.090*
C6	0.8309 (3)	0.9595 (2)	1.0850 (2)	0.0595 (6)
C7	0.6359 (3)	0.8440 (2)	0.8831 (2)	0.0559 (5)
C8	0.4458 (2)	0.97457 (19)	0.71787 (19)	0.0488 (5)
C9	0.3884 (2)	0.85359 (19)	0.62766 (19)	0.0502 (5)
C10	0.2296 (3)	0.8088 (2)	0.5863 (2)	0.0622 (6)
H10	0.1586	0.8521	0.6180	0.075*
C11	0.1759 (3)	0.7012 (2)	0.4989 (2)	0.0750 (8)
H11	0.0695	0.6703	0.4725	0.090*
C12	0.2800 (4)	0.6397 (2)	0.4511 (2)	0.0769 (8)
C13	0.4383 (3)	0.6827 (2)	0.4905 (2)	0.0755 (7)
H13	0.5082	0.6400	0.4573	0.091*
C14	0.4923 (3)	0.7894 (2)	0.5793 (2)	0.0621 (6)
H14	0.5994	0.8184	0.6069	0.074*
C15	0.3749 (2)	1.09761 (19)	0.6912 (2)	0.0513 (5)
C16	0.2483 (2)	1.1126 (2)	0.5730 (2)	0.0560 (5)
C17	0.4278 (3)	1.2223 (2)	0.7746 (2)	0.0620 (6)
C18	0.3811 (12)	1.4663 (7)	0.7837 (10)	0.068 (2)	0.523 (18)
H18A	0.3563	1.5287	0.7150	0.081*	0.523 (18)
H18B	0.4946	1.4746	0.8316	0.081*	0.523 (18)
C19	0.2853 (15)	1.4949 (11)	0.8666 (11)	0.092 (3)	0.523 (18)
H19A	0.1736	1.4875	0.8169	0.138*	0.523 (18)
H19B	0.3120	1.5860	0.9044	0.138*	0.523 (18)
H19C	0.3087	1.4296	0.9317	0.138*	0.523 (18)
H18C	0.3968	1.4029	0.9188	0.105*	0.477 (18)
H18D	0.4638	1.4940	0.8343	0.105*	0.477 (18)
H19D	0.1927	1.5423	0.7192	0.136*	0.477 (18)
H19E	0.2613	1.6103	0.8561	0.136*	0.477 (18)
H19F	0.1498	1.4776	0.8294	0.136*	0.477 (18)
Cl1	0.21456 (12)	0.50444 (8)	0.33944 (8)	0.1331 (5)
F1	0.72205 (17)	1.05606 (16)	1.07956 (13)	0.0850 (5)
F2	0.8855 (2)	0.66854 (19)	0.90845 (19)	0.1238 (7)
N1	0.57876 (19)	0.96329 (16)	0.82386 (16)	0.0544 (5)
H1	0.6319	1.0382	0.8567	0.065*
N2	0.1517 (2)	1.1285 (2)	0.4780 (2)	0.0741 (6)
O1	0.5673 (2)	0.73410 (15)	0.85157 (17)	0.0825 (6)
O2	0.5482 (2)	1.23045 (16)	0.86745 (17)	0.0837 (6)
O3	0.3324 (2)	1.32363 (15)	0.73535 (19)	0.0887 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0522 (12)	0.0567 (11)	0.0446 (11)	−0.0027 (9)	0.0076 (9)	0.0076 (9)
C2	0.0721 (16)	0.0698 (14)	0.0661 (16)	0.0128 (12)	0.0083 (13)	0.0047 (12)
C3	0.0652 (16)	0.0906 (18)	0.082 (2)	0.0167 (13)	0.0062 (15)	0.0179 (16)
C4	0.0527 (14)	0.111 (2)	0.0633 (16)	−0.0062 (14)	0.0010 (12)	0.0252 (15)
C5	0.0707 (16)	0.0961 (18)	0.0465 (14)	−0.0138 (14)	0.0067 (12)	−0.0015 (12)
C6	0.0531 (13)	0.0744 (14)	0.0479 (12)	−0.0006 (10)	0.0138 (10)	0.0029 (10)
C7	0.0562 (12)	0.0551 (11)	0.0467 (12)	−0.0040 (9)	0.0056 (10)	0.0024 (9)
C8	0.0412 (10)	0.0534 (10)	0.0477 (12)	−0.0037 (8)	0.0106 (9)	−0.0004 (9)
C9	0.0500 (11)	0.0491 (10)	0.0445 (11)	0.0017 (8)	0.0076 (9)	0.0003 (8)
C10	0.0521 (12)	0.0533 (11)	0.0711 (15)	0.0009 (9)	0.0098 (11)	−0.0098 (10)
C11	0.0645 (15)	0.0569 (13)	0.0773 (17)	0.0016 (11)	−0.0080 (13)	−0.0112 (12)
C12	0.0947 (19)	0.0522 (12)	0.0568 (15)	0.0208 (12)	−0.0091 (13)	−0.0072 (11)
C13	0.095 (2)	0.0717 (15)	0.0563 (15)	0.0297 (14)	0.0200 (14)	−0.0033 (12)
C14	0.0616 (14)	0.0673 (13)	0.0572 (14)	0.0130 (11)	0.0197 (11)	0.0023 (11)
C15	0.0438 (11)	0.0514 (11)	0.0498 (12)	−0.0033 (8)	0.0056 (9)	−0.0014 (9)
C16	0.0464 (12)	0.0516 (11)	0.0612 (14)	0.0009 (9)	0.0076 (11)	−0.0018 (10)
C17	0.0554 (13)	0.0512 (11)	0.0671 (15)	−0.0036 (10)	0.0063 (12)	−0.0033 (10)
C18	0.084 (4)	0.037 (3)	0.067 (5)	−0.004 (3)	0.007 (4)	0.001 (3)
C19	0.102 (8)	0.082 (6)	0.082 (6)	−0.018 (5)	0.022 (5)	−0.025 (5)
Cl1	0.1606 (9)	0.0804 (5)	0.0965 (6)	0.0416 (5)	−0.0328 (6)	−0.0442 (4)
F1	0.0830 (10)	0.0996 (10)	0.0646 (9)	0.0167 (8)	0.0164 (8)	−0.0169 (8)
F2	0.1283 (15)	0.1036 (12)	0.1083 (14)	0.0450 (11)	0.0014 (11)	−0.0327 (11)
N1	0.0465 (10)	0.0488 (9)	0.0534 (11)	−0.0040 (7)	−0.0005 (8)	−0.0004 (8)
N2	0.0581 (12)	0.0760 (13)	0.0698 (14)	0.0017 (10)	−0.0014 (11)	0.0026 (10)
O1	0.0875 (12)	0.0556 (9)	0.0744 (12)	−0.0176 (8)	−0.0097 (9)	0.0096 (8)
O2	0.0777 (11)	0.0612 (9)	0.0783 (12)	−0.0010 (8)	−0.0145 (10)	−0.0155 (8)
O3	0.0693 (11)	0.0497 (9)	0.1138 (15)	0.0055 (7)	−0.0093 (10)	−0.0193 (9)

Geometric parameters (Å, º) top

C1—C6	1.372 (3)	C11—C12	1.365 (4)
C1—C2	1.382 (3)	C11—H11	0.9300
C1—C7	1.504 (3)	C12—C13	1.376 (4)
C2—F2	1.335 (3)	C12—Cl1	1.734 (2)
C2—C3	1.373 (3)	C13—C14	1.374 (3)
C3—C4	1.355 (4)	C13—H13	0.9300
C3—H3	0.9300	C14—H14	0.9300
C4—C5	1.368 (4)	C15—C16	1.435 (3)
C4—H4	0.9300	C15—C17	1.474 (3)
C5—C6	1.375 (3)	C16—N2	1.139 (3)
C5—H5	0.9300	C17—O2	1.214 (3)
C6—F1	1.358 (3)	C17—O3	1.308 (3)
C7—O1	1.200 (2)	C18—O3	1.475 (6)
C7—N1	1.382 (3)	C18—C19	1.491 (8)
C8—C15	1.365 (3)	C18—H18A	0.9700
C8—N1	1.374 (2)	C18—H18B	0.9700
C8—C9	1.489 (3)	C19—H19A	0.9600
C9—C14	1.379 (3)	C19—H19B	0.9600
C9—C10	1.384 (3)	C19—H19C	0.9600
C10—C11	1.372 (3)	N1—H1	0.8600
C10—H10	0.9300

C6—C1—C2	115.1 (2)	C12—C11—H11	120.3
C6—C1—C7	124.45 (19)	C10—C11—H11	120.3
C2—C1—C7	120.34 (19)	C11—C12—C13	121.0 (2)
F2—C2—C3	117.8 (2)	C11—C12—Cl1	120.3 (2)
F2—C2—C1	118.6 (2)	C13—C12—Cl1	118.7 (2)
C3—C2—C1	123.6 (2)	C14—C13—C12	119.5 (2)
C4—C3—C2	118.2 (3)	C14—C13—H13	120.3
C4—C3—H3	120.9	C12—C13—H13	120.3
C2—C3—H3	120.9	C13—C14—C9	120.3 (2)
C3—C4—C5	121.6 (2)	C13—C14—H14	119.9
C3—C4—H4	119.2	C9—C14—H14	119.9
C5—C4—H4	119.2	C8—C15—C16	119.88 (17)
C4—C5—C6	118.1 (2)	C8—C15—C17	123.52 (18)
C4—C5—H5	121.0	C16—C15—C17	116.48 (17)
C6—C5—H5	121.0	N2—C16—C15	177.2 (2)
F1—C6—C1	118.17 (18)	O2—C17—O3	124.01 (19)
F1—C6—C5	118.3 (2)	O2—C17—C15	123.6 (2)
C1—C6—C5	123.5 (2)	O3—C17—C15	112.34 (18)
O1—C7—N1	123.20 (19)	O3—C18—C19	103.8 (6)
O1—C7—C1	121.33 (19)	O3—C18—H18A	111.0
N1—C7—C1	115.46 (16)	C19—C18—H18A	111.0
C15—C8—N1	120.33 (16)	O3—C18—H18B	111.0
C15—C8—C9	120.59 (17)	C19—C18—H18B	111.0
N1—C8—C9	118.91 (17)	H18A—C18—H18B	109.0
C14—C9—C10	119.25 (19)	C8—N1—C7	126.72 (16)
C14—C9—C8	119.85 (19)	C8—N1—H1	116.6
C10—C9—C8	120.82 (18)	C7—N1—H1	116.6
C11—C10—C9	120.6 (2)	C17—O3—C18	121.6 (5)
C11—C10—H10	119.7	C17—O3—C18'	110.6 (4)
C9—C10—H10	119.7	C18—O3—C18'	26.1 (5)
C12—C11—C10	119.4 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2	0.86	2.05	2.674 (2)	129
N1—H1···F1	0.86	2.36	2.827 (2)	115
C18—H18B···O1ⁱ	0.97	2.58	2.990 (7)	106
C10—H10···N2ⁱⁱ	0.93	2.62	3.302 (3)	131
C5—H5···N2ⁱⁱⁱ	0.93	2.59	3.432 (3)	150

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

Experimental details

Crystal data
Chemical formula	C₁₉H₁₃ClF₂N₂O₃
M_r	390.76
Crystal system, space group	Triclinic, P1
Temperature (K)	298
a, b, c (Å)	8.919 (5), 9.7560 (6), 11.2717 (7)
α, β, γ (°)	91.971 (1), 110.094 (1), 91.449 (1)
V (Å³)	919.9 (5)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.25
Crystal size (mm)	0.23 × 0.20 × 0.10

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	7196, 3556, 2524
R_int	0.053
(sin θ/λ)_max (Å⁻¹)	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.052, 0.154, 1.10
No. of reflections	3556
No. of parameters	265
No. of restraints	6
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.22, −0.31

Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 1999), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2	0.86	2.05	2.674 (2)	128.6
N1—H1···F1	0.86	2.36	2.827 (2)	114.7
C18—H18B···O1ⁱ	0.97	2.58	2.990 (7)	105.6
C10—H10···N2ⁱⁱ	0.93	2.62	3.302 (3)	130.9
C5—H5···N2ⁱⁱⁱ	0.93	2.59	3.432 (3)	150.2

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

References

Bruker (1998). SMART. Bruker AXS Inc., Madison,Wisconsin, USA. Google Scholar
Bruker (1999). SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Creagh, D. C. & Hubbell, J. H. (1992). International Tables for Crystallography, Vol. C, pp. 200–206. Dordrecht: Kluwer. Google Scholar
Heller, D., Drexler, H. J., You, J. & Zhang, S. L. (2004). WO Patent 011 414. Google Scholar
Ibers, J. A. & Hamilton, W. C. (1964). Acta Cryst. 17, 781–782. CrossRef IUCr Journals Web of Science Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. 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.

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 64| Part 12| December 2008| Page o2254

doi:10.1107/S1600536808034818

Open

access