1,2-Bis­(di­phenyl­arsino)­ethane

The title compound, Ph₂AsCH₂CH₂AsPh₂ or C₂₆H₂₄As₂, contains discrete mol­ecules located on an inversion centre. Changes in the C-As-C angle upon coordination are noted.

Key indicators

• Single-crystal X-ray study
• T = 150 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.024
• wR factor = 0.067
• Data-to-parameter ratio = 15.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

During the course of our work on antimony(III) and bismuth(III) complexes of multidentate tertiary phosphine and arsine ligands (Genge et al., 2001), 1,2-bis(diphenylarsino)ethane [(I), dpae] was isolated as colourless needles from an attempted preparation of the complex [SbCl₃(dpae)]. This ligand is commercially available and has been widely used although the crystal structure has not been reported.

The literature contains a number of structural reports concerning transition metal complexes of this ligand: [Pd₃(µ₃-S)₂(dpae)₃][BPh₄]₂ (Matsumoto et al., 1999), [Ru(dpae)₂I₂][BF₄] (Champness et al., 1996), [Os(N)Cl₃(dpae)] (Lam et al., 1993), [ReN(dpae)₂Cl][ClO₄] (Yam et al., 1992), [ReH₅(PPh₃)₂(dpae)] (Costello et al., 1991), [Re₂Cl₄(dpae)₂] and [ReCl(dpae)₂]₂[Re₂Cl₈] (Ferry et al., 1989), and [Ag(NO₃)₂(dpae)] (Pelizzi et al., 1985).

The title structure contains discrete centrosymmetric molecules (Fig. 1 and Table 1) with typical values for the C—C and As—C bond lengths. It has been noted for Ph₃M complexes (M = Sb or As) (Holmes et al., 1998) that the mean C—M—C angle increases upon coordination and the same trend is observed in the compound under study. Inspection of the Cambridge Structural Database (CSD; Allen & Kennard, 1993) gave the average C—As—C bond angle in the small sample (22 observations) of dpae complexes of 103.9° (maximum 106.9°, minimum 98.9°), compared with an angle of 98.4° in the free ligand.

S2. Experimental

The title compound was prepared according to the literature method of Tzschach & Lange (1962). Crystals of suitable quality for single-crystal X-ray diffraction studies were obtained by evaporation of a 1:1 v/v dichloromethane/acetonitrile solution of dpae and SbCl₃ during the attempted preparation of a complex.

Computing details

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1988); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN for Windows (Molecular Structure Corporation, 1997-1999); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976).

Figures

Fig. 1. The molecular structure of (I) showing the atom-labelling scheme. Ellipsoids are drawn at the 40% probability level and H atoms have been omitted for clarity.

1,2-bis(diphenylarsino)ethane

Crystal data

C26H24As2	F(000) = 492
Mr = 486.29	Dx = 1.469 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 9.078 (1) Å	Cell parameters from 25 reflections
b = 5.761 (2) Å	θ = 19.2–23.8°
c = 21.372 (2) Å	µ = 3.05 mm^−1
β = 100.341 (8)°	T = 150 K
V = 1099.6 (4) Å^3	Needle, colourless
Z = 2	0.60 × 0.45 × 0.38 mm

Data collection

Rigaku AFC-7S diffractometer	1700 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.016
Graphite monochromator	θmax = 25.0°, θmin = 2.3°
ω–2θ scans	h = 0→10
Absorption correction: ψ scan (North et al., 1968)	k = 0→6
Tmin = 0.224, Tmax = 0.314	l = −25→24
2061 measured reflections	3 standard reflections every 150 reflections
1932 independent reflections	intensity decay: none

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.024	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.067	Only H-atom displacement parameters refined
S = 1.10	w = 1/[σ^2(Fo^2) + (0.032P)^2 + 0.5P] where P = (Fo^2 + 2Fc^2)/3
1932 reflections	(Δ/σ)max = 0.007
128 parameters	Δρmax = 0.23 e Å^−3
0 restraints	Δρmin = −0.44 e Å^−3

Special details

Experimental. The large collimator (1.0 mm dia) was used because of the large crystal size.

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.

H atoms although observed in later electron density maps were placed in calculated positions and given a common refined adp.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
As1	0.70352 (3)	0.21943 (4)	0.051511 (11)	0.02686 (11)
C1	0.5816 (3)	−0.0362 (4)	0.00791 (11)	0.0283 (5)
H1A	0.6179	−0.0770	−0.0317	0.045 (2)*
H1B	0.5917	−0.1750	0.0357	0.045 (2)*
C2	0.8936 (3)	0.0559 (5)	0.07924 (11)	0.0298 (6)
C3	0.9284 (3)	−0.1583 (5)	0.05606 (13)	0.0376 (6)
H3	0.8545	−0.2411	0.0275	0.045 (2)*
C4	1.0703 (4)	−0.2526 (6)	0.07429 (17)	0.0515 (9)
H4	1.0928	−0.3989	0.0578	0.045 (2)*
C5	1.1782 (3)	−0.1375 (7)	0.11570 (17)	0.0589 (10)
H5	1.2751	−0.2031	0.1279	0.045 (2)*
C6	1.1447 (3)	0.0753 (7)	0.13961 (15)	0.0556 (10)
H6	1.2192	0.1559	0.1684	0.045 (2)*
C7	1.0037 (3)	0.1724 (6)	0.12201 (13)	0.0412 (7)
H7	0.9818	0.3182	0.1390	0.045 (2)*
C8	0.6284 (3)	0.2035 (4)	0.13179 (11)	0.0258 (5)
C9	0.5453 (3)	0.3902 (4)	0.14893 (12)	0.0318 (6)
H9	0.5250	0.5202	0.1214	0.045 (2)*
C10	0.4924 (3)	0.3864 (5)	0.20615 (12)	0.0352 (6)
H10	0.4355	0.5132	0.2174	0.045 (2)*
C11	0.5224 (3)	0.1988 (5)	0.24640 (13)	0.0353 (6)
H11	0.4868	0.1972	0.2856	0.045 (2)*
C12	0.6041 (3)	0.0128 (5)	0.23007 (12)	0.0333 (6)
H12	0.6242	−0.1164	0.2579	0.045 (2)*
C13	0.6566 (3)	0.0151 (5)	0.17289 (11)	0.0297 (5)
H13	0.7123	−0.1132	0.1618	0.045 (2)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
As1	0.02922 (16)	0.02813 (17)	0.02292 (16)	−0.00342 (10)	0.00383 (11)	0.00190 (10)
C1	0.0296 (13)	0.0321 (13)	0.0230 (12)	−0.0022 (11)	0.0042 (10)	−0.0030 (10)
C2	0.0257 (13)	0.0398 (15)	0.0246 (13)	−0.0041 (11)	0.0065 (10)	0.0058 (11)
C3	0.0379 (15)	0.0428 (16)	0.0344 (15)	0.0029 (13)	0.0124 (12)	0.0065 (13)
C4	0.0519 (19)	0.056 (2)	0.054 (2)	0.0174 (16)	0.0288 (17)	0.0229 (16)
C5	0.0305 (16)	0.091 (3)	0.058 (2)	0.0135 (18)	0.0170 (15)	0.040 (2)
C6	0.0301 (15)	0.089 (3)	0.0447 (18)	−0.0183 (17)	−0.0018 (13)	0.0208 (19)
C7	0.0351 (14)	0.0522 (18)	0.0369 (15)	−0.0138 (14)	0.0077 (12)	0.0047 (14)
C8	0.0248 (12)	0.0300 (13)	0.0212 (12)	−0.0046 (10)	0.0004 (9)	−0.0028 (10)
C9	0.0348 (14)	0.0256 (13)	0.0338 (14)	0.0000 (11)	0.0029 (11)	0.0000 (11)
C10	0.0346 (14)	0.0375 (15)	0.0335 (14)	0.0038 (12)	0.0062 (11)	−0.0077 (12)
C11	0.0335 (14)	0.0485 (17)	0.0242 (13)	−0.0034 (12)	0.0064 (11)	−0.0058 (12)
C12	0.0353 (14)	0.0392 (15)	0.0248 (12)	−0.0006 (12)	0.0042 (10)	0.0030 (11)
C13	0.0302 (13)	0.0329 (13)	0.0251 (12)	0.0015 (11)	0.0025 (10)	−0.0007 (11)

Geometric parameters (Å, º)

As1—C8	1.959 (2)	C6—C7	1.385 (4)
As1—C2	1.962 (3)	C6—H6	0.9500
As1—C1	1.973 (2)	C7—H7	0.9500
C1—C1^i	1.518 (5)	C8—C13	1.391 (3)
C1—H1A	0.9900	C8—C9	1.400 (4)
C1—H1B	0.9900	C9—C10	1.392 (4)
C2—C3	1.387 (4)	C9—H9	0.9500
C2—C7	1.399 (4)	C10—C11	1.378 (4)
C3—C4	1.388 (4)	C10—H10	0.9500
C3—H3	0.9500	C11—C12	1.383 (4)
C4—C5	1.368 (5)	C11—H11	0.9500
C4—H4	0.9500	C12—C13	1.389 (3)
C5—C6	1.383 (5)	C12—H12	0.9500
C5—H5	0.9500	C13—H13	0.9500
C8—As1—C2	97.95 (10)	C7—C6—H6	119.6
C8—As1—C1	97.18 (10)	C6—C7—C2	120.0 (3)
C2—As1—C1	99.93 (11)	C6—C7—H7	120.0
C1^i—C1—As1	110.0 (2)	C2—C7—H7	120.0
C1^i—C1—H1A	109.7	C13—C8—C9	118.8 (2)
As1—C1—H1A	109.7	C13—C8—As1	122.43 (19)
C1^i—C1—H1B	109.7	C9—C8—As1	118.81 (19)
As1—C1—H1B	109.7	C10—C9—C8	120.3 (2)
H1A—C1—H1B	108.2	C10—C9—H9	119.8
C3—C2—C7	118.6 (3)	C8—C9—H9	119.8
C3—C2—As1	124.3 (2)	C11—C10—C9	120.0 (2)
C7—C2—As1	117.0 (2)	C11—C10—H10	120.0
C2—C3—C4	120.5 (3)	C9—C10—H10	120.0
C2—C3—H3	119.8	C10—C11—C12	120.3 (2)
C4—C3—H3	119.8	C10—C11—H11	119.8
C5—C4—C3	120.8 (3)	C12—C11—H11	119.8
C5—C4—H4	119.6	C11—C12—C13	119.9 (3)
C3—C4—H4	119.6	C11—C12—H12	120.0
C4—C5—C6	119.3 (3)	C13—C12—H12	120.0
C4—C5—H5	120.3	C12—C13—C8	120.7 (2)
C6—C5—H5	120.3	C12—C13—H13	119.7
C5—C6—C7	120.7 (3)	C8—C13—H13	119.7
C5—C6—H6	119.6

Symmetry code: (i) −x+1, −y, −z.