O,O′-Diisopropyl S-[2-(benzene­sulfon­amido)­eth­yl]phospho­rodithio­ate

Wu, H.-F.; Liu, X.-Y.; Zhang, F.-H.; He, Y.-X.

doi:10.1107/S160053681105536X

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 68| Part 2| February 2012| Page o282

doi:10.1107/S160053681105536X

Open

access

O,O′-Diisopropyl S-[2-(benzenesulfonamido)ethyl]phosphorodithioate

Hai-Feng Wu,^a ^* Xin-Yi Liu,^a Fan-Hua Zhang ^a and Yun-Xiao He ^a

^aSinochem Ningbo (Group) Co. Ltd, Ningbo, Zhejiang 315000, People's Republic of China
^*Correspondence e-mail: wuhaifeng@sinochem.com

(Received 7 December 2011; accepted 23 December 2011; online 7 January 2012)

The molecular conformation of the title compound, C₁₄H₂₄NO₄PS₃, the selective herbicide bensulide, is stabilized by a weak intramolecular C—H⋯S interaction. In the crystal, chains are formed through intermolecular N—H⋯S hydrogen bonds.

Related literature

For applications of N-(β-diorganodithiophosphorylethyl) aryl and alkyl sulfonamides in the field of agrochemicals, see: Llewellyn & Chester (1963 ). Bensulide is a selective organophosphate herbicide which is mainly used on vegetable crops such as carrots, cucumbers, peppers and melons, see: Meister (1992 ). For the synthesis, see: Llewellyn & Jeffrey (1978 ).

Experimental

Crystal data

C₁₄H₂₄NO₄PS₃
M_r = 397.49
Monoclinic, P 2₁ /n
a = 8.6431 (17) Å
b = 24.465 (5) Å
c = 9.875 (2) Å
β = 104.99 (3)°
V = 2017.1 (8) Å³
Z = 4
Mo Kα radiation
μ = 0.46 mm⁻¹
T = 293 K
0.37 × 0.35 × 0.27 mm

Data collection

Rigaku R-AXIS RAPID CCD diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ) T_min = 0.843, T_max = 0.883
19632 measured reflections
4605 independent reflections
3083 reflections with I > 2σ(I)
R_int = 0.029

Refinement

R[F² > 2σ(F²)] = 0.041
wR(F²) = 0.127
S = 1.11
4605 reflections
208 parameters
H-atom parameters constrained
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.40 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N—H0A⋯S1ⁱ	0.86	2.86	3.496 (2)	132
C7—H7B⋯S1	0.97	2.83	3.447 (3)	122
Symmetry code: (i) $[x+{\script{1\over 2}}, -y+{\script{3\over 2}}, z+{\script{1\over 2}}]$ .

Data collection: RAPID-AUTO (Rigaku, 1998 ); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2004 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPII (Johnson, 1976 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053681105536X/zs2173sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053681105536X/zs2173Isup2.hkl

Supporting information file. DOI: 10.1107/S160053681105536X/zs2173Isup3.cml

checkCIF report

Comment top

N-(β-Diorganodithiophosphorylethyl) aryl and alkyl sulfonamides are known for their applications in the field of agrochemicals because of their significant biological properties (Llewellyn et al., 1963). The title compound C₁₄H₂₄NO₄PS₃ (I), with the common name bensulide, is a selective organophosphate herbicide which is mainly used on vegetable crops such as carrots, cucumbers, peppers and melons (Meister, 1992). This typical organic phosphorus compound is one of our plant products that can be synthesized by combining the sodium salt of 2-(phenylsulfonamido)ethyl sulfate (II) and O,O'-diisopropyl phosphorodithioate (III) (Llewellyn et al., 1978) (Fig. 3).

In the title compound (Fig. 1), bond distances and angles are as expected. The P atom is coordinated by two S atoms and two O atoms. The O1—P—S1, S1—P—S2 and O2—P—S1 bond angles [117.91 (7), 114.48 (5), 111.46 (7)°, respectively] are larger than those for angles O2—P—S2, O1—P—O2 and O1—P—S2 [108.85 (8), 102.35 (9), 100.58 (7)°, respectively], indicating a distorted tetrahedral configuration. The molecular conformation is stabilized by weak intramolecular C—H···S and C—H···O interactions and one-dimensional chains are formed through intermolecular N—H···S hydrogen bonds (Table 1, Fig. 2).

Related literature top

For applications of N-(β-diorganodithiophosphorylethyl) aryl and alkyl sulfonamides in the field of agrochemicals, see: Llewellyn & Chester (1963). Bensulide is a selective organophosphate herbicide which is mainly used on vegetable crops such as carrots, cucumbers, peppers and melons, see: Meister (1992). For the synthesis, see: Llewellyn & Jeffrey (1978).

Experimental top

A 30% aqueous solution of sodium 2-(phenylsulfonamido)ethyl sulfate [(II), 0.5mol] was added to a 30% aqueous solution of sodium O,O'-diisopropyl phosphorodithioate [(III), 0.5 mol]. Addition of 50% aqueous sodium hydroxide brought the pH to 10.5. The mixture was then heated to 85 °C for 4 h with vigorous stirring after which the reaction flask was cooled to 25 °C. The pH was lowered from 12 to approximately 8 by the addition of concentrated sulfuric acid. The product was extracted with toluene (400 ml), washed with 2% sodium bicarbonate solution followed by a saturated sodium chloride solution, then dried and evaporated. Recrystallization from toluene gave colourless blocks of (I).

Computing details top

Data collection: RAPID-AUTO (Rigaku, 1998); cell refinement: RAPID-AUTO (Rigaku, 1998); data reduction: CrystalStructure (Rigaku/MSC, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. An ORTEP view of the title compound with displacement ellipsoids drawn at the 35% probability level.
	Fig. 2. Part of the crystal packing of (I). Weak intermolecular interactions are shown as dashed lines.
	Fig. 3. Reaction scheme for the synthesis of (I).

O,O'-Diisopropyl S-[2-(benzenesulfonamido)ethyl]dithiophosphate top

Crystal data top

C₁₄H₂₄NO₄PS₃	F(000) = 840
M_r = 397.49	D_x = 1.309 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 19632 reflections
a = 8.6431 (17) Å	θ = 3.3–27.5°
b = 24.465 (5) Å	µ = 0.46 mm⁻¹
c = 9.875 (2) Å	T = 293 K
β = 104.99 (3)°	Block, colorless
V = 2017.1 (8) Å³	0.37 × 0.35 × 0.27 mm
Z = 4

Data collection top

Rigaku R-AXIS RAPID CCD diffractometer	4605 independent reflections
Radiation source: fine-focus sealed tube	3083 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.029
ω scans	θ_max = 27.5°, θ_min = 3.3°
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	h = −11→10
T_min = 0.843, T_max = 0.883	k = −31→31
19632 measured reflections	l = −12→12

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)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.127	H-atom parameters constrained
S = 1.11	w = 1/[σ²(F_o²) + (0.0534P)² + 0.6749P] where P = (F_o² + 2F_c²)/3
4605 reflections	(Δ/σ)_max = 0.001
208 parameters	Δρ_max = 0.35 e Å⁻³
0 restraints	Δρ_min = −0.40 e Å⁻³

Crystal data top

C₁₄H₂₄NO₄PS₃	V = 2017.1 (8) Å³
M_r = 397.49	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 8.6431 (17) Å	µ = 0.46 mm⁻¹
b = 24.465 (5) Å	T = 293 K
c = 9.875 (2) Å	0.37 × 0.35 × 0.27 mm
β = 104.99 (3)°

Data collection top

Rigaku R-AXIS RAPID CCD diffractometer	4605 independent reflections
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	3083 reflections with I > 2σ(I)
T_min = 0.843, T_max = 0.883	R_int = 0.029
19632 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.041	0 restraints
wR(F²) = 0.127	H-atom parameters constrained
S = 1.11	Δρ_max = 0.35 e Å⁻³
4605 reflections	Δρ_min = −0.40 e Å⁻³
208 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
P	0.25939 (7)	0.64011 (3)	0.36909 (6)	0.04780 (17)
S1	0.36714 (8)	0.63940 (4)	0.22205 (8)	0.0740 (2)
S2	0.40173 (9)	0.66439 (3)	0.56352 (7)	0.0654 (2)
S3	0.47902 (8)	0.85949 (3)	0.34382 (7)	0.05828 (19)
N	0.5557 (2)	0.81061 (8)	0.4499 (2)	0.0591 (5)
H0A	0.6574	0.8085	0.4858	0.071*
O1	0.19173 (18)	0.58432 (6)	0.40940 (18)	0.0543 (4)
O2	0.10605 (17)	0.67690 (7)	0.33022 (17)	0.0520 (4)
O3	0.6077 (2)	0.89486 (8)	0.3366 (2)	0.0812 (6)
O4	0.3819 (3)	0.83522 (9)	0.2196 (2)	0.0808 (6)
C1	0.2942 (3)	0.53593 (10)	0.4530 (3)	0.0570 (6)
H1A	0.4064	0.5460	0.4633	0.068*
C2	0.2453 (5)	0.49360 (13)	0.3407 (4)	0.0934 (11)
H2A	0.2640	0.5072	0.2551	0.140*
H2B	0.1336	0.4855	0.3263	0.140*
H2C	0.3070	0.4610	0.3686	0.140*
C3	0.2729 (5)	0.51819 (14)	0.5913 (4)	0.0915 (10)
H3A	0.3072	0.5469	0.6587	0.137*
H3B	0.3358	0.4860	0.6219	0.137*
H3C	0.1620	0.5102	0.5825	0.137*
C4	−0.0043 (3)	0.68091 (10)	0.4232 (3)	0.0551 (6)
H4A	0.0481	0.6651	0.5148	0.066*
C5	−0.1513 (3)	0.64868 (14)	0.3583 (4)	0.0869 (10)
H5A	−0.1231	0.6110	0.3520	0.130*
H5B	−0.1995	0.6625	0.2661	0.130*
H5C	−0.2258	0.6518	0.4150	0.130*
C6	−0.0328 (4)	0.74050 (12)	0.4411 (4)	0.0874 (10)
H6A	0.0667	0.7580	0.4862	0.131*
H6B	−0.1070	0.7449	0.4978	0.131*
H6C	−0.0763	0.7569	0.3510	0.131*
C7	0.5288 (3)	0.71656 (11)	0.5167 (3)	0.0647 (7)
H7A	0.6232	0.7214	0.5941	0.078*
H7B	0.5640	0.7041	0.4363	0.078*
C8	0.4462 (3)	0.76989 (10)	0.4830 (3)	0.0601 (6)
H8A	0.3538	0.7657	0.4035	0.072*
H8B	0.4088	0.7823	0.5623	0.072*
C9	0.3490 (3)	0.89472 (9)	0.4243 (2)	0.0505 (5)
C10	0.4098 (4)	0.93520 (10)	0.5218 (3)	0.0628 (7)
H10A	0.5180	0.9441	0.5437	0.075*
C11	0.3071 (4)	0.96202 (12)	0.5857 (3)	0.0766 (8)
H11A	0.3463	0.9896	0.6502	0.092*
C12	0.1486 (4)	0.94845 (13)	0.5552 (3)	0.0768 (8)
H12A	0.0810	0.9666	0.5996	0.092*
C13	0.0884 (4)	0.90801 (14)	0.4589 (3)	0.0757 (8)
H13A	−0.0196	0.8988	0.4388	0.091*
C14	0.1885 (3)	0.88125 (11)	0.3926 (3)	0.0623 (7)
H14A	0.1481	0.8542	0.3267	0.075*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
P	0.0387 (3)	0.0591 (4)	0.0454 (3)	0.0051 (3)	0.0104 (2)	0.0005 (3)
S1	0.0534 (4)	0.1117 (6)	0.0642 (5)	0.0140 (4)	0.0283 (3)	0.0037 (4)
S2	0.0685 (4)	0.0623 (4)	0.0540 (4)	−0.0086 (3)	−0.0046 (3)	0.0056 (3)
S3	0.0680 (4)	0.0611 (4)	0.0495 (4)	−0.0070 (3)	0.0221 (3)	−0.0053 (3)
N	0.0486 (11)	0.0557 (12)	0.0750 (15)	−0.0015 (10)	0.0195 (10)	−0.0034 (10)
O1	0.0462 (8)	0.0532 (9)	0.0630 (11)	0.0029 (7)	0.0130 (8)	−0.0035 (8)
O2	0.0439 (8)	0.0652 (10)	0.0501 (10)	0.0141 (7)	0.0181 (7)	0.0079 (7)
O3	0.0895 (14)	0.0746 (12)	0.0930 (16)	−0.0182 (11)	0.0482 (12)	0.0031 (11)
O4	0.0968 (15)	0.0956 (15)	0.0493 (11)	−0.0054 (12)	0.0176 (10)	−0.0195 (10)
C1	0.0523 (13)	0.0521 (13)	0.0626 (16)	0.0069 (11)	0.0076 (11)	−0.0040 (11)
C2	0.101 (2)	0.0698 (19)	0.095 (3)	0.0190 (18)	−0.001 (2)	−0.0266 (17)
C3	0.121 (3)	0.078 (2)	0.080 (2)	0.010 (2)	0.035 (2)	0.0165 (17)
C4	0.0505 (13)	0.0622 (14)	0.0597 (15)	0.0066 (12)	0.0268 (11)	−0.0014 (12)
C5	0.0572 (16)	0.097 (2)	0.116 (3)	−0.0085 (16)	0.0391 (18)	−0.025 (2)
C6	0.089 (2)	0.0681 (18)	0.123 (3)	0.0079 (17)	0.061 (2)	−0.0056 (18)
C7	0.0460 (13)	0.0616 (15)	0.0792 (19)	0.0012 (12)	0.0031 (12)	0.0021 (13)
C8	0.0564 (14)	0.0547 (14)	0.0730 (18)	−0.0022 (12)	0.0237 (13)	−0.0054 (12)
C9	0.0616 (14)	0.0488 (12)	0.0403 (12)	−0.0011 (11)	0.0118 (10)	0.0044 (9)
C10	0.0729 (17)	0.0571 (14)	0.0581 (16)	−0.0088 (13)	0.0165 (13)	−0.0068 (12)
C11	0.103 (2)	0.0637 (17)	0.0653 (19)	0.0023 (17)	0.0264 (17)	−0.0104 (14)
C12	0.090 (2)	0.0785 (19)	0.0666 (19)	0.0278 (18)	0.0287 (17)	0.0078 (15)
C13	0.0605 (16)	0.096 (2)	0.069 (2)	0.0095 (16)	0.0140 (14)	0.0131 (17)
C14	0.0616 (15)	0.0693 (16)	0.0513 (15)	−0.0022 (13)	0.0059 (12)	−0.0012 (12)

Geometric parameters (Å, º) top

P—O2	1.5654 (16)	C4—H4A	0.9800
P—O1	1.5761 (18)	C5—H5A	0.9600
P—S1	1.9171 (10)	C5—H5B	0.9600
P—S2	2.0811 (11)	C5—H5C	0.9600
S2—C7	1.820 (3)	C6—H6A	0.9600
S3—O4	1.425 (2)	C6—H6B	0.9600
S3—O3	1.4254 (19)	C6—H6C	0.9600
S3—N	1.615 (2)	C7—C8	1.484 (4)
S3—C9	1.761 (3)	C7—H7A	0.9700
N—C8	1.468 (3)	C7—H7B	0.9700
N—H0A	0.8600	C8—H8A	0.9700
O1—C1	1.474 (3)	C8—H8B	0.9700
O2—C4	1.489 (3)	C9—C14	1.381 (3)
C1—C3	1.489 (4)	C9—C10	1.386 (3)
C1—C2	1.496 (4)	C10—C11	1.381 (4)
C1—H1A	0.9800	C10—H10A	0.9300
C2—H2A	0.9600	C11—C12	1.365 (4)
C2—H2B	0.9600	C11—H11A	0.9300
C2—H2C	0.9600	C12—C13	1.377 (4)
C3—H3A	0.9600	C12—H12A	0.9300
C3—H3B	0.9600	C13—C14	1.378 (4)
C3—H3C	0.9600	C13—H13A	0.9300
C4—C5	1.492 (4)	C14—H14A	0.9300
C4—C6	1.497 (4)

O2—P—O1	102.35 (9)	C4—C5—H5A	109.5
O2—P—S1	111.46 (7)	C4—C5—H5B	109.5
O1—P—S1	117.91 (7)	H5A—C5—H5B	109.5
O2—P—S2	108.85 (8)	C4—C5—H5C	109.5
O1—P—S2	100.58 (7)	H5A—C5—H5C	109.5
S1—P—S2	114.48 (5)	H5B—C5—H5C	109.5
C7—S2—P	102.56 (10)	C4—C6—H6A	109.5
O4—S3—O3	120.22 (14)	C4—C6—H6B	109.5
O4—S3—N	107.55 (13)	H6A—C6—H6B	109.5
O3—S3—N	106.68 (13)	C4—C6—H6C	109.5
O4—S3—C9	106.87 (12)	H6A—C6—H6C	109.5
O3—S3—C9	108.84 (12)	H6B—C6—H6C	109.5
N—S3—C9	105.83 (11)	C8—C7—S2	112.74 (18)
C8—N—S3	117.80 (17)	C8—C7—H7A	109.0
C8—N—H0A	121.1	S2—C7—H7A	109.0
S3—N—H0A	121.1	C8—C7—H7B	109.0
C1—O1—P	122.36 (15)	S2—C7—H7B	109.0
C4—O2—P	121.58 (15)	H7A—C7—H7B	107.8
O1—C1—C3	107.1 (2)	N—C8—C7	110.2 (2)
O1—C1—C2	107.8 (2)	N—C8—H8A	109.6
C3—C1—C2	113.6 (3)	C7—C8—H8A	109.6
O1—C1—H1A	109.4	N—C8—H8B	109.6
C3—C1—H1A	109.4	C7—C8—H8B	109.6
C2—C1—H1A	109.4	H8A—C8—H8B	108.1
C1—C2—H2A	109.5	C14—C9—C10	120.4 (2)
C1—C2—H2B	109.5	C14—C9—S3	120.14 (19)
H2A—C2—H2B	109.5	C10—C9—S3	119.4 (2)
C1—C2—H2C	109.5	C11—C10—C9	118.9 (3)
H2A—C2—H2C	109.5	C11—C10—H10A	120.5
H2B—C2—H2C	109.5	C9—C10—H10A	120.5
C1—C3—H3A	109.5	C12—C11—C10	120.7 (3)
C1—C3—H3B	109.5	C12—C11—H11A	119.7
H3A—C3—H3B	109.5	C10—C11—H11A	119.7
C1—C3—H3C	109.5	C11—C12—C13	120.4 (3)
H3A—C3—H3C	109.5	C11—C12—H12A	119.8
H3B—C3—H3C	109.5	C13—C12—H12A	119.8
O2—C4—C5	108.1 (2)	C12—C13—C14	119.8 (3)
O2—C4—C6	106.8 (2)	C12—C13—H13A	120.1
C5—C4—C6	114.7 (2)	C14—C13—H13A	120.1
O2—C4—H4A	109.0	C13—C14—C9	119.7 (3)
C5—C4—H4A	109.0	C13—C14—H14A	120.1
C6—C4—H4A	109.0	C9—C14—H14A	120.1

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N—H0A···S1ⁱ	0.86	2.86	3.496 (2)	132
C7—H7B···S1	0.97	2.83	3.447 (3)	122
C8—H8A···O4	0.97	2.55	2.980 (3)	107
C14—H14A···O4	0.93	2.55	2.908 (4)	103

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

Experimental details

Crystal data
Chemical formula	C₁₄H₂₄NO₄PS₃
M_r	397.49
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	293
a, b, c (Å)	8.6431 (17), 24.465 (5), 9.875 (2)
β (°)	104.99 (3)
V (Å³)	2017.1 (8)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.46
Crystal size (mm)	0.37 × 0.35 × 0.27

Data collection
Diffractometer	Rigaku R-AXIS RAPID CCD diffractometer
Absorption correction	Multi-scan (ABSCOR; Higashi, 1995)
T_min, T_max	0.843, 0.883
No. of measured, independent and observed [I > 2σ(I)] reflections	19632, 4605, 3083
R_int	0.029
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.041, 0.127, 1.11
No. of reflections	4605
No. of parameters	208
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.35, −0.40

Computer programs: RAPID-AUTO (Rigaku, 1998), CrystalStructure (Rigaku/MSC, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEPII (Johnson, 1976).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N—H0A···S1ⁱ	0.86	2.86	3.496 (2)	132
C7—H7B···S1	0.97	2.83	3.447 (3)	122

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

Acknowledgements

We thank Professor Yueqing Zheng (Ningbo University, Ningbo, China) for helpful discussions and Wenxiang Huang for the X-ray data collection.

References

Higashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan. Google Scholar
Johnson, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National Laboratory, Tennessee, USA. Google Scholar
Llewellyn, W. & Chester, L. (1963). US Patent No. 3 205 253. Google Scholar
Llewellyn, W. & Jeffrey, D. (1978). US Patent No. 4 117 043. Google Scholar
Meister, R. T. (1992). Farm Chemicals Handbook. Willoghby, OH: Meister Publishing Company. Google Scholar
Rigaku (1998). RAPID-AUTO. Rigaku Corporation, Tokyo, Japan. Google Scholar
Rigaku/MSC (2004). CrystalStructure. Rigaku/MSC Inc., The Woodlands, Texas, USA. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar