supplementary materials


HTML versionpdf versioncif file3d viewstructure factorssupplementary materialsCIF check reportsimilar papers Open access

Acta Cryst. (2008). E64, o2171    [ doi:10.1107/S1600536808033023 ]

Diethylammonium anilino(methoxy)phosphinate

Z. Fu and X. Liu

Abstract top

The title compound, [Et2NH2][(EtO)PO2(C6H5NH)] or C4H12N+·C8H11NO3P-, is a molecular salt with two anions containing PO3N groupings and two cations in the asymmetric unit. A network of N-H...O hydrogen bonds link the cations and anions into a two-dimensional network.

Comment top

N-substituted phosphoramidic acids are useful agents in the synthesis of pyrophosphate groups (Quin & Jankowski,1994). However the structures of these kinds of materials have not been well characterized. By the use of the O,N-substituted phosphoramidic acids as ligands in the preparation of new metal phosphate frameworks, we obtained the title compound as a salt of the O,N-substituted phosphoramidic acid.

As shown in Fig. 1, the asymmetric unit of the title compound is composed of two diethyl-amine cations, and two N-ethoxyphosphoryl-phenylamide anions. The geometrical parameters of the independent anions are similar. The phosphorus atoms have tetrahedral coordination geometries. The shortest P—O bond lengths correspond to the P=O double bonds. The longest P—O distances are due to the influence of the –OEt group (Andrianov et al.,1977). The O—P—O and O—P—N bond angles range from 102.961 (98)–119.158 (108)° and 105.126 (113)–112.197 (117)°, indicating that the geometries of the tetrahedra are slightly distorted.

Hydrogen bonds exist between the diethyl-amine cations and the N-ethoxyphosphoryl-phenylamide anions. The N—H···O connections result a two dimensional packing motif (Fig. 2).

Related literature top

For background on N-substituted phosphoramidic acids, see: Quin & Jankowski (1994). For a corresponding dimer complex with similar P—O and P—N connections, see: Andrianov et al. (1977).

Experimental top

A solution of aniline (12.5 mmol) and 12.5 mmol of Et2NH in 15 ml of ether was added to a solution of 12.5 mmol of ethyl phosphorodichloridate in 15 ml of ether. After 20 h, the solution was filtered and the filtrate was evaporated to give a powder. The powder was dissolved in 30 ml of an acetone-water mixture (1:1) containing 1 g of NaOH. After 10 min, the solvent was evaporated and the residue dried in vacuo. Recrystalization of the precipitate from a chloroform solution yielded crystals of the title compound.

Refinement top

H atoms were positioned geometrically and refined using a riding model, with N—H = 0.86–0.90 Å, C—H = 0.93–0.97 Å and with Uiso(H) = 1.2 (1.5 for methyl groups) times Ueq(C). >.

Computing details top

Data collection: SMART (Bruker, 1996); cell refinement: SAINT (Bruker, 1996); data reduction: SAINT (Bruker, 1996); 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
[Figure 1] Fig. 1. The molecular structure of (I), with atom labels and 50% probability displacement ellipsoids for non-H atoms. The red dashed lines indicate the hydrogen bonds.
[Figure 2] Fig. 2. The packing of (I), viewed down the b axis, showing the N—H···O hydrogen bonds between the diethylamine cations and the N-ethoxy phosphoryl-phenylamide anions. H-atoms have been omitted for clarity.
Diethylammonium anilino(methoxy)phosphinate top
Crystal data top
C4H12N+·C8H11NO3P−F(000) = 1184
Mr = 274.29Dx = 1.242 Mg m−3
Orthorhombic, Pna21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P2c-2nCell parameters from 4847 reflections
a = 14.341 (3) Åθ = 3.3–25.0°
b = 12.785 (2) ŵ = 0.19 mm−1
c = 15.997 (3) ÅT = 173 K
V = 2933.0 (9) Å3Needle-like, colorless
Z = 80.4 × 0.2 × 0.08 mm
Data collection top
Bruker SMART CCD
diffractometer		4847 independent reflections
Radiation source: fine-focus sealed tube4043 reflections with I > 2σ(I)
graphiteRint = 0.002
ω scansθmax = 25.0°, θmin = 3.3°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		h = −17→17
Tmin = 0.957, Tmax = 0.989k = −15→15
5062 measured reflectionsl = −19→18
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.039H-atom parameters constrained
wR(F2) = 0.081 w = 1/[σ2(Fo2) + (0.0363P)2 + 0.5497P]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max = 0.001
4847 reflectionsΔρmax = 0.16 e Å−3
325 parametersΔρmin = −0.23 e Å−3
1 restraintAbsolute structure: Flack (1983), 2649 Friedel pairs
Primary atom site location: structure-invariant direct methodsFlack parameter: 0.06 (4)
Crystal data top
C4H12N+·C8H11NO3P−V = 2933.0 (9) Å3
Mr = 274.29Z = 8
Orthorhombic, Pna21Mo Kα radiation
a = 14.341 (3) ŵ = 0.19 mm−1
b = 12.785 (2) ÅT = 173 K
c = 15.997 (3) Å0.4 × 0.2 × 0.08 mm
Data collection top
Bruker SMART CCD
diffractometer		4847 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		4043 reflections with I > 2σ(I)
Tmin = 0.957, Tmax = 0.989Rint = 0.002
5062 measured reflectionsθmax = 25.0°
Refinement top
R[F2 > 2σ(F2)] = 0.039H-atom parameters constrained
wR(F2) = 0.081Δρmax = 0.16 e Å−3
S = 1.03Δρmin = −0.23 e Å−3
4847 reflectionsAbsolute structure: Flack (1983), 2649 Friedel pairs
325 parametersFlack parameter: 0.06 (4)
1 restraint
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
xyzUiso*/Ueq
N10.50725 (13)0.16964 (16)0.52519 (13)0.0230 (5)
H1B0.53740.22420.54140.028*
N40.30305 (14)−0.01440 (16)0.74774 (12)0.0265 (5)
H4A0.3436−0.00130.70610.032*
H4B0.2451−0.00690.72700.032*
C10.4316 (2)0.1694 (2)0.27143 (19)0.0359 (7)
H1A0.41510.16960.21520.043*
C20.45479 (18)0.2624 (2)0.31172 (18)0.0336 (7)
H2A0.45410.32510.28230.040*
C30.47881 (17)0.2616 (2)0.39546 (16)0.0269 (6)
H3A0.49370.32420.42190.032*
C40.48107 (16)0.1682 (2)0.44095 (16)0.0220 (6)
C50.45765 (17)0.0754 (2)0.39961 (16)0.0242 (6)
H5A0.45830.01220.42850.029*
C60.43349 (18)0.0772 (2)0.31564 (18)0.0315 (7)
H6A0.41830.01500.28880.038*
C70.63999 (18)−0.0209 (2)0.5543 (2)0.0407 (7)
H7A0.67030.00430.60460.049*
H7B0.65560.02610.50870.049*
C80.6729 (2)−0.1300 (2)0.53435 (19)0.0415 (7)
H8A0.7393−0.12970.52660.062*
H8B0.6432−0.15400.48410.062*
H8C0.6572−0.17600.57970.062*
C210.3111 (3)−0.1992 (2)0.7038 (2)0.0540 (9)
H21A0.3195−0.26930.72400.081*
H21B0.3596−0.18280.66450.081*
H21C0.2516−0.19350.67690.081*
C220.3154 (2)−0.1243 (2)0.77572 (17)0.0351 (7)
H22A0.2671−0.14170.81570.042*
H22B0.3752−0.13120.80360.042*
C230.3172 (2)0.0639 (2)0.81480 (18)0.0359 (7)
H23A0.37850.05450.83910.043*
H23B0.27130.05290.85850.043*
C240.3086 (2)0.1737 (2)0.7821 (2)0.0434 (8)
H24A0.31850.22240.82690.065*
H24B0.24740.18380.75910.065*
H24C0.35440.18510.73930.065*
P10.48758 (4)0.07915 (5)0.59834 (4)0.02230 (16)
O10.52914 (12)0.12003 (13)0.67646 (11)0.0297 (4)
O20.54000 (11)−0.02352 (13)0.56616 (11)0.0259 (4)
O30.38708 (11)0.04682 (12)0.59813 (12)0.0272 (4)
N20.55256 (14)0.33041 (17)0.73990 (14)0.0283 (5)
H2B0.55020.26870.71870.034*
N30.72854 (14)0.40960 (16)0.50343 (13)0.0267 (5)
H3B0.78200.42250.53100.032*
H3C0.68260.40460.54160.032*
C90.55185 (17)0.3353 (2)0.82782 (16)0.0233 (6)
C100.55401 (18)0.2428 (2)0.87430 (17)0.0302 (7)
H10A0.55600.17890.84660.036*
C110.55331 (19)0.2445 (2)0.96026 (18)0.0343 (7)
H11A0.55520.18200.98990.041*
C120.54987 (18)0.3381 (2)1.00280 (18)0.0346 (7)
H12A0.54920.33911.06090.042*
C130.5474 (2)0.4306 (2)0.95808 (18)0.0336 (7)
H13A0.54510.49410.98630.040*
C140.54840 (19)0.4294 (2)0.87124 (17)0.0298 (7)
H14A0.54670.49220.84190.036*
C150.37515 (18)0.4351 (2)0.66248 (18)0.0357 (7)
H15A0.38790.36130.65420.043*
H15B0.34790.46240.61150.043*
C160.3085 (2)0.4486 (3)0.7328 (2)0.0479 (8)
H16A0.25160.41210.72050.072*
H16B0.29550.52160.74040.072*
H16C0.33530.42070.78310.072*
C170.7673 (2)0.2234 (2)0.5187 (2)0.0412 (7)
H17A0.77250.15850.48890.062*
H17B0.72200.21640.56250.062*
H17C0.82670.24130.54240.062*
C180.73711 (19)0.3085 (2)0.45931 (17)0.0315 (6)
H18A0.78240.31490.41460.038*
H18B0.67750.29000.43470.038*
C190.70839 (19)0.4987 (2)0.44723 (17)0.0326 (6)
H19A0.64870.48760.42010.039*
H19B0.75590.50230.40410.039*
C200.7060 (2)0.6010 (2)0.4943 (2)0.0475 (8)
H20A0.69280.65700.45620.071*
H20B0.76530.61280.52040.071*
H20C0.65830.59810.53640.071*
P20.55732 (4)0.42782 (5)0.67233 (4)0.02279 (16)
O40.56495 (11)0.37700 (13)0.58821 (11)0.0282 (4)
O50.62869 (12)0.50728 (13)0.69568 (10)0.0306 (4)
O60.46099 (11)0.48965 (13)0.68041 (12)0.0294 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0269 (11)0.0204 (12)0.0219 (11)−0.0046 (9)−0.0028 (9)−0.0019 (9)
N40.0218 (12)0.0335 (13)0.0241 (11)0.0008 (9)−0.0012 (9)0.0045 (10)
C10.0436 (17)0.0395 (18)0.0247 (15)0.0050 (14)−0.0059 (13)−0.0015 (14)
C20.0404 (16)0.0300 (16)0.0304 (16)0.0006 (13)−0.0034 (12)0.0025 (14)
C30.0305 (14)0.0226 (15)0.0276 (16)0.0018 (12)0.0013 (11)−0.0045 (12)
C40.0181 (13)0.0249 (15)0.0231 (15)0.0032 (11)0.0024 (10)−0.0017 (11)
C50.0255 (14)0.0204 (14)0.0268 (16)−0.0006 (11)−0.0014 (11)−0.0014 (12)
C60.0319 (16)0.0342 (16)0.0284 (16)−0.0013 (12)−0.0040 (12)−0.0077 (14)
C70.0223 (15)0.0437 (18)0.0561 (19)0.0006 (13)0.0027 (13)−0.0137 (15)
C80.0409 (17)0.0400 (18)0.0435 (18)0.0134 (14)0.0066 (14)−0.0004 (14)
C210.073 (2)0.0354 (18)0.054 (2)−0.0014 (17)−0.0147 (17)0.0019 (16)
C220.0366 (16)0.0322 (16)0.0365 (17)0.0011 (13)−0.0049 (13)0.0116 (14)
C230.0386 (17)0.0401 (17)0.0291 (15)0.0011 (13)−0.0048 (13)−0.0042 (14)
C240.0464 (18)0.0368 (17)0.0470 (19)−0.0006 (14)0.0049 (15)−0.0052 (14)
P10.0261 (4)0.0211 (3)0.0197 (3)0.0005 (3)−0.0011 (3)0.0006 (3)
O10.0411 (11)0.0250 (9)0.0230 (10)0.0006 (8)−0.0046 (9)0.0006 (9)
O20.0239 (10)0.0239 (10)0.0298 (11)0.0019 (7)0.0000 (7)−0.0027 (8)
O30.0225 (9)0.0320 (10)0.0272 (10)−0.0021 (7)0.0011 (9)0.0028 (9)
N20.0400 (13)0.0201 (12)0.0247 (13)−0.0001 (10)0.0015 (10)−0.0041 (9)
N30.0250 (12)0.0307 (13)0.0245 (12)0.0010 (9)−0.0009 (9)0.0021 (10)
C90.0230 (14)0.0255 (15)0.0213 (15)−0.0023 (11)−0.0003 (11)−0.0002 (12)
C100.0362 (16)0.0238 (15)0.0306 (17)−0.0010 (12)0.0000 (12)−0.0010 (13)
C110.0428 (18)0.0298 (16)0.0304 (17)−0.0056 (14)−0.0008 (12)0.0090 (13)
C120.0383 (17)0.0454 (19)0.0202 (16)−0.0005 (13)−0.0033 (12)0.0007 (13)
C130.0422 (18)0.0308 (17)0.0279 (16)0.0054 (13)−0.0027 (12)−0.0089 (13)
C140.0374 (16)0.0256 (15)0.0264 (16)0.0020 (12)−0.0050 (12)0.0008 (12)
C150.0281 (14)0.0456 (17)0.0334 (16)−0.0015 (13)−0.0007 (14)−0.0054 (14)
C160.0383 (18)0.060 (2)0.045 (2)−0.0006 (16)0.0093 (15)−0.0028 (16)
C170.0384 (16)0.0291 (16)0.056 (2)−0.0014 (13)0.0010 (14)0.0036 (14)
C180.0276 (15)0.0327 (16)0.0341 (16)−0.0017 (12)0.0008 (11)−0.0017 (13)
C190.0342 (16)0.0357 (17)0.0277 (14)0.0065 (13)0.0007 (11)0.0078 (13)
C200.054 (2)0.0384 (18)0.050 (2)0.0042 (15)0.0052 (16)0.0090 (15)
P20.0246 (3)0.0225 (3)0.0213 (3)−0.0017 (3)0.0002 (3)−0.0004 (3)
O40.0334 (10)0.0304 (10)0.0208 (10)−0.0043 (8)0.0031 (8)−0.0011 (9)
O50.0292 (10)0.0307 (10)0.0320 (11)−0.0062 (8)−0.0044 (8)0.0011 (8)
O60.0264 (9)0.0299 (10)0.0319 (10)0.0012 (8)−0.0018 (8)−0.0045 (9)
Geometric parameters (Å, °) top
N1—C41.399 (3)N2—C91.408 (3)
N1—P11.670 (2)N2—P21.651 (2)
N1—H1B0.8600N2—H2B0.8600
N4—C231.481 (3)N3—C181.478 (3)
N4—C221.485 (3)N3—C191.480 (3)
N4—H4A0.9000N3—H3B0.9000
N4—H4B0.9000N3—H3C0.9000
C1—C61.374 (4)C9—C141.391 (4)
C1—C21.393 (4)C9—C101.397 (4)
C1—H1A0.9300C10—C111.375 (4)
C2—C31.383 (4)C10—H10A0.9300
C2—H2A0.9300C11—C121.378 (4)
C3—C41.399 (4)C11—H11A0.9300
C3—H3A0.9300C12—C131.382 (4)
C4—C51.399 (3)C12—H12A0.9300
C5—C61.387 (4)C13—C141.389 (4)
C5—H5A0.9300C13—H13A0.9300
C6—H6A0.9300C14—H14A0.9300
C7—O21.447 (3)C15—O61.444 (3)
C7—C81.507 (4)C15—C161.487 (4)
C7—H7A0.9700C15—H15A0.9700
C7—H7B0.9700C15—H15B0.9700
C8—H8A0.9600C16—H16A0.9600
C8—H8B0.9600C16—H16B0.9600
C8—H8C0.9600C16—H16C0.9600
C21—C221.498 (4)C17—C181.507 (4)
C21—H21A0.9600C17—H17A0.9600
C21—H21B0.9600C17—H17B0.9600
C21—H21C0.9600C17—H17C0.9600
C22—H22A0.9700C18—H18A0.9700
C22—H22B0.9700C18—H18B0.9700
C23—C241.504 (4)C19—C201.509 (4)
C23—H23A0.9700C19—H19A0.9700
C23—H23B0.9700C19—H19B0.9700
C24—H24A0.9600C20—H20A0.9600
C24—H24B0.9600C20—H20B0.9600
C24—H24C0.9600C20—H20C0.9600
P1—O11.4798 (19)P2—O51.4897 (18)
P1—O31.4994 (17)P2—O41.4983 (19)
P1—O21.5979 (18)P2—O61.5969 (17)
C4—N1—P1128.36 (18)C9—N2—P2128.40 (19)
C4—N1—H1B115.8C9—N2—H2B115.8
P1—N1—H1B115.8P2—N2—H2B115.8
C23—N4—C22113.87 (19)C18—N3—C19113.6 (2)
C23—N4—H4A108.8C18—N3—H3B108.9
C22—N4—H4A108.8C19—N3—H3B108.9
C23—N4—H4B108.8C18—N3—H3C108.9
C22—N4—H4B108.8C19—N3—H3C108.9
H4A—N4—H4B107.7H3B—N3—H3C107.7
C6—C1—C2119.3 (3)C14—C9—C10117.9 (2)
C6—C1—H1A120.4C14—C9—N2122.5 (2)
C2—C1—H1A120.4C10—C9—N2119.6 (2)
C3—C2—C1120.1 (3)C11—C10—C9121.2 (3)
C3—C2—H2A120.0C11—C10—H10A119.4
C1—C2—H2A120.0C9—C10—H10A119.4
C2—C3—C4121.1 (3)C10—C11—C12120.6 (3)
C2—C3—H3A119.5C10—C11—H11A119.7
C4—C3—H3A119.5C12—C11—H11A119.7
C3—C4—N1119.7 (2)C11—C12—C13119.2 (3)
C3—C4—C5118.2 (2)C11—C12—H12A120.4
N1—C4—C5122.1 (2)C13—C12—H12A120.4
C6—C5—C4120.2 (2)C12—C13—C14120.6 (3)
C6—C5—H5A119.9C12—C13—H13A119.7
C4—C5—H5A119.9C14—C13—H13A119.7
C1—C6—C5121.2 (3)C13—C14—C9120.6 (3)
C1—C6—H6A119.4C13—C14—H14A119.7
C5—C6—H6A119.4C9—C14—H14A119.7
O2—C7—C8108.4 (2)O6—C15—C16110.0 (2)
O2—C7—H7A110.0O6—C15—H15A109.7
C8—C7—H7A110.0C16—C15—H15A109.7
O2—C7—H7B110.0O6—C15—H15B109.7
C8—C7—H7B110.0C16—C15—H15B109.7
H7A—C7—H7B108.4H15A—C15—H15B108.2
C7—C8—H8A109.5C15—C16—H16A109.5
C7—C8—H8B109.5C15—C16—H16B109.5
H8A—C8—H8B109.5H16A—C16—H16B109.5
C7—C8—H8C109.5C15—C16—H16C109.5
H8A—C8—H8C109.5H16A—C16—H16C109.5
H8B—C8—H8C109.5H16B—C16—H16C109.5
C22—C21—H21A109.5C18—C17—H17A109.5
C22—C21—H21B109.5C18—C17—H17B109.5
H21A—C21—H21B109.5H17A—C17—H17B109.5
C22—C21—H21C109.5C18—C17—H17C109.5
H21A—C21—H21C109.5H17A—C17—H17C109.5
H21B—C21—H21C109.5H17B—C17—H17C109.5
N4—C22—C21111.6 (2)N3—C18—C17110.7 (2)
N4—C22—H22A109.3N3—C18—H18A109.5
C21—C22—H22A109.3C17—C18—H18A109.5
N4—C22—H22B109.3N3—C18—H18B109.5
C21—C22—H22B109.3C17—C18—H18B109.5
H22A—C22—H22B108.0H18A—C18—H18B108.1
N4—C23—C24111.6 (2)N3—C19—C20111.6 (2)
N4—C23—H23A109.3N3—C19—H19A109.3
C24—C23—H23A109.3C20—C19—H19A109.3
N4—C23—H23B109.3N3—C19—H19B109.3
C24—C23—H23B109.3C20—C19—H19B109.3
H23A—C23—H23B108.0H19A—C19—H19B108.0
C23—C24—H24A109.5C19—C20—H20A109.5
C23—C24—H24B109.5C19—C20—H20B109.5
H24A—C24—H24B109.5H20A—C20—H20B109.5
C23—C24—H24C109.5C19—C20—H20C109.5
H24A—C24—H24C109.5H20A—C20—H20C109.5
H24B—C24—H24C109.5H20B—C20—H20C109.5
O1—P1—O3119.11 (11)O5—P2—O4118.09 (10)
O1—P1—O2111.87 (10)O5—P2—O6103.68 (10)
O3—P1—O2103.01 (9)O4—P2—O6110.52 (10)
O1—P1—N1106.21 (10)O5—P2—N2112.25 (11)
O3—P1—N1110.60 (10)O4—P2—N2105.31 (11)
O2—P1—N1105.30 (10)O6—P2—N2106.54 (10)
C7—O2—P1119.30 (16)C15—O6—P2118.84 (16)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1B···O40.862.132.954 (3)161
N2—H2B···O10.862.042.895 (3)173
N3—H3C···O40.901.882.742 (3)160
N4—H4A···O30.901.942.792 (3)158
N3—H3B···O3i0.901.892.788 (3)174
N4—H4B···O5ii0.901.742.637 (3)172
Symmetry codes: (i) x+1/2, −y+1/2, z; (ii) x−1/2, −y+1/2, z.
Table 1
Selected geometric parameters (Å) top
P1—O11.4798 (19)P2—O51.4897 (18)
P1—O31.4994 (17)P2—O41.4983 (19)
P1—O21.5979 (18)P2—O61.5969 (17)
Table 2
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1B···O40.862.132.954 (3)161
N2—H2B···O10.862.042.895 (3)173
N3—H3C···O40.901.882.742 (3)160
N4—H4A···O30.901.942.792 (3)158
N3—H3B···O3i0.901.892.788 (3)174
N4—H4B···O5ii0.901.742.637 (3)172
Symmetry codes: (i) x+1/2, −y+1/2, z; (ii) x−1/2, −y+1/2, z.
Acknowledgements top

The authors thank the NSFFPC (No. 2003 F006) and the SRP program of the SCUT for financial support.

references
References top

Andrianov, V. G., Kalinin, A. E. & Struchkov, Yu. T. (1977). Zh. Strukt. Khim. 18, 310–317.

Bruker (1996). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.

Flack, H. D. (1983). Acta Cryst. A39, 876–881.

Quin, L. D. & Jankowski, S. (1994). J. Org. Chem. 59, 4402–4409.

Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.