Diphenyl­phosphane selenide

Dornhaus, F.; Lerner, H.-W.; Bolte, M.

doi:10.1107/S1600536807062575

Diphenylphosphane selenide

The title compound, C₁₂H₁₁PSe, crystallizes with two molecules in the asymmetric unit. The bond lengths and angles of these two molecules are similar but they differ significantly in the dihedral angle between the two phenyl rings [72.70 (10) and 82.07 (9)°]. The molecules are connected by P—H

Se hydrogen bonds into zigzag chains running along the a axis.

Read article Similar articles

Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807062575/at2507sup1.cif Contains datablocks I, global
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536807062575/at2507Isup2.hkl Contains datablock I

CCDC reference: 673093

checkCIF report

Key indicators

Single-crystal X-ray study
T = 173 K
Mean (C-C) = 0.005 Å
R factor = 0.041
wR factor = 0.107
Data-to-parameter ratio = 16.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.93
PLAT166_ALERT_4_C S.U's Given on Coordinates for calc-flagged ....         H1
PLAT166_ALERT_4_C S.U's Given on Coordinates for calc-flagged ....        H1A

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.934
            Tmax scaled      0.539 Tmin scaled      0.325

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

Comment top

Transition metal complexes with phosphine ligands, PR₃ (R = alkyl, aryl, H) play a big role in homogeneous catalysis. A disadvantage of these ligands is their air sensitivity. Phosphoranes and phosphine chalcogenides are to be found compared with phosphines much more stable toward air oxidation. We report here the synthesis and the X-ray crystal structure analysis of Ph₂HPSe (Ph = C₆H₅). The synthesis of the title compound was achieved by the reaction of Ph₂PH (Dornhaus et al., 2006) with grey Se in THF at room temperature as indicated in the equation below.

The title compound, C₁₂H₁₁PSe, crystallizes with two molecules in the asymmetric unit. Bond lengths and angles of these two molecules are similar but they differ significantly in the dihedral angle between the two phenyl rings [72.70 (10)° and 82.07 (9)°, respectively]. The molecules are connected by P—H···Se hydrogen bonds to zigzag chains running along the a axis.

Related literature top

For related literature, see: Dornhaus et al. (2006).

Experimental top

A mixture of diphenylphosphine Ph₂PH (1.5 g, 8 mmol) and grey Se (1.0 g, 12.7 mmol) in 10 ml tetrahydrofuran was stirred for 24 h at room temperature. After filtering single crystals of Ph₂HPSe were obtained from the filtrate at room temperature (yield 70%).

Computing details top

Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA (Stoe & Cie, 2001); data reduction: X-AREA (Stoe & Cie, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 1991); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).

Figures top

	Fig. 1. Perspective view of the two molecules of the title compound with the atom numbering scheme; displacement ellipsoids are at the 50% probability level. H atoms are drawn as small spheres of arbitrary radii.
	Fig. 2. Partial packing diagram of the title compound. H atoms bonded to C have been omitted. Hydrogen bonds are shown as dashed lines.
	Fig. 3. Preparation of the title compound.

Diphenylphosphane selenide top

Crystal data top

C₁₂H₁₁PSe	F(000) = 1056
M_r = 265.14	D_x = 1.563 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 32153 reflections
a = 6.0901 (3) Å	θ = 2.0–26.0°
b = 32.3775 (18) Å	µ = 3.43 mm⁻¹
c = 11.5057 (6) Å	T = 173 K
β = 96.741 (4)°	Rod, colourless
V = 2253.0 (2) Å³	0.39 × 0.22 × 0.18 mm
Z = 8

Data collection top

Stoe IPDSII two-circle diffractometer	4221 independent reflections
Radiation source: fine-focus sealed tube	3625 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.071
ω scans	θ_max = 25.6°, θ_min = 1.9°
Absorption correction: multi-scan (MULABS; Spek, 2003; Blessing, 1995)	h = −7→7
T_min = 0.348, T_max = 0.577	k = −39→39
31769 measured reflections	l = −13→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)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.107	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ²(F_o²) + (0.0645P)² + 0.5807P] where P = (F_o² + 2F_c²)/3
4221 reflections	(Δ/σ)_max = 0.001
255 parameters	Δρ_max = 0.60 e Å⁻³
0 restraints	Δρ_min = −0.82 e Å⁻³

Crystal data top

C₁₂H₁₁PSe	V = 2253.0 (2) Å³
M_r = 265.14	Z = 8
Monoclinic, P2₁/c	Mo Kα radiation
a = 6.0901 (3) Å	µ = 3.43 mm⁻¹
b = 32.3775 (18) Å	T = 173 K
c = 11.5057 (6) Å	0.39 × 0.22 × 0.18 mm
β = 96.741 (4)°

Data collection top

Stoe IPDSII two-circle diffractometer	4221 independent reflections
Absorption correction: multi-scan (MULABS; Spek, 2003; Blessing, 1995)	3625 reflections with I > 2σ(I)
T_min = 0.348, T_max = 0.577	R_int = 0.071
31769 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.041	0 restraints
wR(F²) = 0.107	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	Δρ_max = 0.60 e Å⁻³
4221 reflections	Δρ_min = −0.82 e Å⁻³
255 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
P1	0.09835 (13)	0.33963 (3)	0.69820 (7)	0.03192 (19)
H1	−0.047 (4)	0.34283 (9)	0.778 (2)	0.038*
Se1	0.41802 (5)	0.342757 (11)	0.79157 (3)	0.03972 (13)
C1	0.0409 (5)	0.38172 (10)	0.5955 (3)	0.0350 (7)
C2	−0.1574 (6)	0.40311 (11)	0.5927 (4)	0.0474 (9)
H2	−0.2620	0.3957	0.6442	0.057*
C3	−0.2018 (8)	0.43557 (13)	0.5136 (4)	0.0593 (11)
H3	−0.3369	0.4504	0.5118	0.071*
C4	−0.0525 (8)	0.44628 (13)	0.4389 (4)	0.0594 (11)
H4	−0.0839	0.4685	0.3856	0.071*
C5	0.1453 (7)	0.42461 (14)	0.4409 (4)	0.0593 (11)
H5	0.2482	0.4317	0.3883	0.071*
C6	0.1913 (6)	0.39280 (12)	0.5196 (3)	0.0485 (9)
H6	0.3275	0.3783	0.5218	0.058*
C11	0.0369 (5)	0.29206 (9)	0.6194 (3)	0.0322 (6)
C12	0.1862 (6)	0.27636 (11)	0.5477 (3)	0.0401 (7)
H12	0.3223	0.2902	0.5427	0.048*
C13	0.1371 (6)	0.24062 (11)	0.4838 (3)	0.0459 (8)
H13	0.2381	0.2302	0.4341	0.055*
C14	−0.0590 (6)	0.22023 (11)	0.4927 (3)	0.0466 (9)
H14	−0.0922	0.1956	0.4492	0.056*
C15	−0.2081 (6)	0.23531 (11)	0.5645 (3)	0.0444 (8)
H15	−0.3427	0.2210	0.5701	0.053*
C16	−0.1609 (5)	0.27127 (10)	0.6284 (3)	0.0394 (7)
H16	−0.2627	0.2816	0.6778	0.047*
P1A	0.62143 (12)	0.40880 (2)	0.04919 (7)	0.03085 (19)
H1A	0.450 (4)	0.40567 (8)	−0.032 (2)	0.037*
Se1A	0.90789 (5)	0.403223 (11)	−0.03664 (3)	0.03914 (13)
C1A	0.5929 (5)	0.36893 (10)	0.1560 (3)	0.0317 (6)
C2A	0.3935 (6)	0.34771 (11)	0.1572 (3)	0.0395 (8)
H2A	0.2705	0.3545	0.1019	0.047*
C3A	0.3743 (6)	0.31662 (12)	0.2392 (4)	0.0481 (9)
H3A	0.2386	0.3022	0.2397	0.058*
C4A	0.5534 (6)	0.30689 (12)	0.3198 (3)	0.0485 (9)
H4A	0.5413	0.2855	0.3751	0.058*
C5A	0.7517 (7)	0.32840 (13)	0.3200 (3)	0.0496 (9)
H5A	0.8736	0.3218	0.3762	0.059*
C6A	0.7721 (6)	0.35908 (12)	0.2394 (3)	0.0416 (8)
H6A	0.9078	0.3736	0.2402	0.050*
C11A	0.5967 (5)	0.45790 (10)	0.1226 (3)	0.0313 (6)
C12A	0.7636 (5)	0.48738 (11)	0.1288 (3)	0.0379 (7)
H12A	0.8942	0.4823	0.0933	0.045*
C13A	0.7382 (6)	0.52438 (10)	0.1875 (3)	0.0415 (8)
H13A	0.8526	0.5445	0.1923	0.050*
C14A	0.5483 (6)	0.53210 (11)	0.2387 (3)	0.0433 (8)
H14A	0.5326	0.5573	0.2790	0.052*
C15A	0.3807 (6)	0.50289 (11)	0.2312 (3)	0.0453 (8)
H15A	0.2490	0.5084	0.2653	0.054*
C16A	0.4043 (5)	0.46583 (11)	0.1742 (3)	0.0397 (7)
H16A	0.2898	0.4458	0.1702	0.048*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
P1	0.0343 (4)	0.0320 (4)	0.0296 (4)	−0.0020 (3)	0.0044 (3)	−0.0027 (3)
Se1	0.0381 (2)	0.0440 (2)	0.0356 (2)	−0.00395 (13)	−0.00179 (14)	−0.00289 (14)
C1	0.0412 (16)	0.0327 (16)	0.0304 (17)	−0.0033 (13)	0.0010 (13)	−0.0015 (13)
C2	0.049 (2)	0.045 (2)	0.048 (2)	0.0050 (16)	0.0043 (17)	0.0004 (16)
C3	0.067 (3)	0.046 (2)	0.062 (3)	0.0133 (19)	−0.006 (2)	0.0061 (19)
C4	0.085 (3)	0.045 (2)	0.044 (2)	−0.006 (2)	−0.013 (2)	0.0096 (17)
C5	0.067 (3)	0.067 (3)	0.043 (2)	−0.017 (2)	0.0028 (19)	0.0141 (19)
C6	0.048 (2)	0.049 (2)	0.048 (2)	−0.0063 (17)	0.0035 (17)	0.0046 (17)
C11	0.0348 (15)	0.0297 (15)	0.0316 (16)	−0.0012 (12)	0.0023 (12)	−0.0004 (12)
C12	0.0363 (16)	0.0416 (18)	0.043 (2)	−0.0017 (14)	0.0072 (14)	−0.0047 (15)
C13	0.050 (2)	0.043 (2)	0.045 (2)	0.0052 (16)	0.0070 (16)	−0.0130 (16)
C14	0.063 (2)	0.0311 (17)	0.043 (2)	−0.0027 (16)	−0.0056 (17)	−0.0049 (15)
C15	0.0415 (18)	0.0385 (18)	0.051 (2)	−0.0077 (14)	−0.0028 (16)	0.0022 (16)
C16	0.0345 (16)	0.0392 (18)	0.044 (2)	−0.0009 (13)	0.0041 (14)	−0.0005 (15)
P1A	0.0289 (4)	0.0327 (4)	0.0303 (4)	0.0010 (3)	0.0006 (3)	−0.0005 (3)
Se1A	0.0353 (2)	0.0450 (2)	0.0380 (2)	0.00360 (13)	0.00777 (14)	0.00016 (14)
C1A	0.0341 (15)	0.0314 (16)	0.0292 (16)	0.0021 (12)	0.0021 (12)	−0.0008 (12)
C2A	0.0345 (16)	0.0426 (19)	0.041 (2)	0.0030 (14)	0.0044 (14)	0.0026 (14)
C3A	0.0429 (18)	0.048 (2)	0.055 (2)	0.0011 (16)	0.0121 (16)	0.0112 (17)
C4A	0.055 (2)	0.051 (2)	0.041 (2)	0.0041 (17)	0.0118 (16)	0.0115 (16)
C5A	0.058 (2)	0.055 (2)	0.0336 (19)	0.0100 (18)	−0.0036 (16)	0.0056 (16)
C6A	0.0403 (18)	0.045 (2)	0.0378 (19)	−0.0002 (14)	−0.0026 (14)	−0.0015 (15)
C11A	0.0324 (15)	0.0321 (16)	0.0285 (16)	0.0020 (12)	0.0003 (12)	0.0019 (12)
C12A	0.0335 (16)	0.0408 (18)	0.0397 (19)	−0.0030 (13)	0.0060 (13)	0.0019 (14)
C13A	0.0419 (18)	0.0347 (17)	0.047 (2)	−0.0068 (14)	0.0017 (15)	0.0029 (15)
C14A	0.053 (2)	0.0322 (17)	0.044 (2)	0.0031 (15)	0.0042 (16)	−0.0043 (14)
C15A	0.0408 (18)	0.044 (2)	0.053 (2)	0.0030 (15)	0.0130 (16)	−0.0077 (17)
C16A	0.0335 (16)	0.0383 (18)	0.048 (2)	−0.0031 (13)	0.0084 (14)	−0.0030 (15)

Geometric parameters (Å, º) top

P1—C11	1.804 (3)	P1A—C1A	1.804 (3)
P1—C1	1.810 (3)	P1A—C11A	1.815 (3)
P1—Se1	2.1127 (9)	P1A—Se1A	2.1109 (9)
P1—H1	1.3486	P1A—H1A	1.3164
C1—C6	1.385 (5)	C1A—C2A	1.397 (5)
C1—C2	1.389 (5)	C1A—C6A	1.403 (4)
C2—C3	1.395 (5)	C2A—C3A	1.394 (5)
C2—H2	0.9500	C2A—H2A	0.9500
C3—C4	1.367 (7)	C3A—C4A	1.383 (5)
C3—H3	0.9500	C3A—H3A	0.9500
C4—C5	1.392 (7)	C4A—C5A	1.394 (6)
C4—H4	0.9500	C4A—H4A	0.9500
C5—C6	1.378 (6)	C5A—C6A	1.374 (5)
C5—H5	0.9500	C5A—H5A	0.9500
C6—H6	0.9500	C6A—H6A	0.9500
C11—C12	1.393 (5)	C11A—C12A	1.390 (4)
C11—C16	1.395 (4)	C11A—C16A	1.399 (5)
C12—C13	1.385 (5)	C12A—C13A	1.392 (5)
C12—H12	0.9500	C12A—H12A	0.9500
C13—C14	1.379 (5)	C13A—C14A	1.382 (5)
C13—H13	0.9500	C13A—H13A	0.9500
C14—C15	1.386 (5)	C14A—C15A	1.387 (5)
C14—H14	0.9500	C14A—H14A	0.9500
C15—C16	1.388 (5)	C15A—C16A	1.383 (5)
C15—H15	0.9500	C15A—H15A	0.9500
C16—H16	0.9500	C16A—H16A	0.9500

C11—P1—C1	107.56 (14)	C1A—P1A—C11A	106.86 (14)
C11—P1—Se1	114.89 (10)	C1A—P1A—Se1A	114.09 (10)
C1—P1—Se1	113.06 (11)	C11A—P1A—Se1A	114.26 (10)
C11—P1—H1	107.0	C1A—P1A—H1A	107.1
C1—P1—H1	107.0	C11A—P1A—H1A	107.1
Se1—P1—H1	107.0	Se1A—P1A—H1A	107.1
C6—C1—C2	119.6 (3)	C2A—C1A—C6A	119.3 (3)
C6—C1—P1	121.0 (3)	C2A—C1A—P1A	120.8 (2)
C2—C1—P1	119.4 (3)	C6A—C1A—P1A	119.9 (3)
C1—C2—C3	119.5 (4)	C3A—C2A—C1A	120.3 (3)
C1—C2—H2	120.3	C3A—C2A—H2A	119.9
C3—C2—H2	120.3	C1A—C2A—H2A	119.9
C4—C3—C2	120.6 (4)	C4A—C3A—C2A	119.7 (3)
C4—C3—H3	119.7	C4A—C3A—H3A	120.1
C2—C3—H3	119.7	C2A—C3A—H3A	120.1
C3—C4—C5	120.0 (4)	C3A—C4A—C5A	120.2 (3)
C3—C4—H4	120.0	C3A—C4A—H4A	119.9
C5—C4—H4	120.0	C5A—C4A—H4A	119.9
C6—C5—C4	119.8 (4)	C6A—C5A—C4A	120.4 (3)
C6—C5—H5	120.1	C6A—C5A—H5A	119.8
C4—C5—H5	120.1	C4A—C5A—H5A	119.8
C5—C6—C1	120.6 (4)	C5A—C6A—C1A	120.1 (3)
C5—C6—H6	119.7	C5A—C6A—H6A	120.0
C1—C6—H6	119.7	C1A—C6A—H6A	120.0
C12—C11—C16	119.8 (3)	C12A—C11A—C16A	119.7 (3)
C12—C11—P1	119.8 (2)	C12A—C11A—P1A	121.7 (2)
C16—C11—P1	120.3 (2)	C16A—C11A—P1A	118.6 (2)
C13—C12—C11	120.2 (3)	C11A—C12A—C13A	119.6 (3)
C13—C12—H12	119.9	C11A—C12A—H12A	120.2
C11—C12—H12	119.9	C13A—C12A—H12A	120.2
C14—C13—C12	119.7 (3)	C14A—C13A—C12A	120.6 (3)
C14—C13—H13	120.1	C14A—C13A—H13A	119.7
C12—C13—H13	120.1	C12A—C13A—H13A	119.7
C13—C14—C15	120.6 (3)	C13A—C14A—C15A	119.8 (3)
C13—C14—H14	119.7	C13A—C14A—H14A	120.1
C15—C14—H14	119.7	C15A—C14A—H14A	120.1
C14—C15—C16	120.1 (3)	C16A—C15A—C14A	120.3 (3)
C14—C15—H15	120.0	C16A—C15A—H15A	119.8
C16—C15—H15	120.0	C14A—C15A—H15A	119.8
C15—C16—C11	119.5 (3)	C15A—C16A—C11A	120.0 (3)
C15—C16—H16	120.2	C15A—C16A—H16A	120.0
C11—C16—H16	120.2	C11A—C16A—H16A	120.0

C11—P1—C1—C6	−80.3 (3)	C11A—P1A—C1A—C2A	101.1 (3)
Se1—P1—C1—C6	47.6 (3)	Se1A—P1A—C1A—C2A	−131.6 (2)
C11—P1—C1—C2	99.5 (3)	C11A—P1A—C1A—C6A	−78.6 (3)
Se1—P1—C1—C2	−132.6 (3)	Se1A—P1A—C1A—C6A	48.7 (3)
C6—C1—C2—C3	−0.2 (5)	C6A—C1A—C2A—C3A	−1.1 (5)
P1—C1—C2—C3	179.9 (3)	P1A—C1A—C2A—C3A	179.2 (3)
C1—C2—C3—C4	0.4 (6)	C1A—C2A—C3A—C4A	0.2 (6)
C2—C3—C4—C5	0.2 (7)	C2A—C3A—C4A—C5A	0.8 (6)
C3—C4—C5—C6	−0.9 (7)	C3A—C4A—C5A—C6A	−0.8 (6)
C4—C5—C6—C1	1.1 (6)	C4A—C5A—C6A—C1A	−0.1 (6)
C2—C1—C6—C5	−0.5 (6)	C2A—C1A—C6A—C5A	1.0 (5)
P1—C1—C6—C5	179.3 (3)	P1A—C1A—C6A—C5A	−179.3 (3)
C1—P1—C11—C12	78.0 (3)	C1A—P1A—C11A—C12A	122.0 (3)
Se1—P1—C11—C12	−48.9 (3)	Se1A—P1A—C11A—C12A	−5.2 (3)
C1—P1—C11—C16	−101.0 (3)	C1A—P1A—C11A—C16A	−57.7 (3)
Se1—P1—C11—C16	132.2 (2)	Se1A—P1A—C11A—C16A	175.1 (2)
C16—C11—C12—C13	1.2 (5)	C16A—C11A—C12A—C13A	0.6 (5)
P1—C11—C12—C13	−177.8 (3)	P1A—C11A—C12A—C13A	−179.1 (3)
C11—C12—C13—C14	−1.0 (5)	C11A—C12A—C13A—C14A	−0.4 (5)
C12—C13—C14—C15	0.4 (6)	C12A—C13A—C14A—C15A	−0.4 (6)
C13—C14—C15—C16	0.0 (6)	C13A—C14A—C15A—C16A	1.0 (6)
C14—C15—C16—C11	0.2 (5)	C14A—C15A—C16A—C11A	−0.8 (6)
C12—C11—C16—C15	−0.8 (5)	C12A—C11A—C16A—C15A	0.0 (5)
P1—C11—C16—C15	178.2 (3)	P1A—C11A—C16A—C15A	179.8 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
P1A—H1A···Se1ⁱ	1.32	2.87	3.7458 (9)	123
P1—H1···Se1Aⁱⁱ	1.35	2.93	3.9652 (9)	132

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

Experimental details

Crystal data
Chemical formula	C₁₂H₁₁PSe
M_r	265.14
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	173
a, b, c (Å)	6.0901 (3), 32.3775 (18), 11.5057 (6)
β (°)	96.741 (4)
V (Å³)	2253.0 (2)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	3.43
Crystal size (mm)	0.39 × 0.22 × 0.18

Data collection
Diffractometer	Stoe IPDSII two-circle diffractometer
Absorption correction	Multi-scan (MULABS; Spek, 2003; Blessing, 1995)
T_min, T_max	0.348, 0.577
No. of measured, independent and observed [I > 2σ(I)] reflections	31769, 4221, 3625
R_int	0.071
(sin θ/λ)_max (Å⁻¹)	0.608

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.041, 0.107, 1.04
No. of reflections	4221
No. of parameters	255
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.60, −0.82

Computer programs: X-AREA (Stoe & Cie, 2001), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), XP in SHELXTL-Plus (Sheldrick, 1991), SHELXL97 and PLATON (Spek, 2003).