supplementary materials


wm2756 scheme

Acta Cryst. (2013). E69, m473-m474    [ doi:10.1107/S1600536813019284 ]

Bis(cyclohexylammonium) tetrachlorido(oxalato)stannate(IV)

M. Sarr, A. Diasse-Sarr, W. Diallo, L. Plasseraud and H. Cattey

Abstract top

The title salt, (C6H14N)2[Sn(C2O4)Cl4], was obtained as a by-product from the reaction between 2C6H14N+·C2O42-·1.5H2O and SnCl2·2H2O. The cyclohexylammonium cation has a chair conformation. The complex anion consists of an oxalate anion chelating the SnCl4 moiety, resulting in a distorted octahedral coordination sphere of the SnIV atom with the O atoms in equatorial cis positions. In the crystal, cations and anions are linked through N-H...O and N-H...Cl interactions into a layered arrangement parallel to (100).

Comment top

Various applications of organotin(IV) compounds exist in many fields, e.g. related to agriculture, medicine, anti-fouling paints and wood preservatives (Evans & Karpel, 1985). Therefore new organotin compounds have been the research subject of many groups (Ballmann et al., 2009; Meriem et al., 1989; Ng & Kumar Das, 1997; Zhang et al., 2006). Our group has previously reported several halogenidotin(IV) derivatives (Diallo et al., 2009; Qamar-Kane & Diop, 2010). In this work, we report the results of the reaction between (C6H14N)2(C2O4).1.5H2O with SnCl2.2H2O leading to the formation of the title compound, (C6H14N)2[Sn(C2O4)Cl4], (I).

The asymmetric unit of (I) consists of an oxalate anion chelating a SnCl4 moiety (Fig. 1). The C—O distances in the oxalate anion [C1—O3 = 1.227 (4) Å; C2—O4 = 1.217 (4) Å; C1—O1 = 1.286 (4) Å; C2—O2 = 1.290 (4) Å] indicate double and single bonds, respectively. The Sn—O distances [Sn1—O1 = 2.155 (2) Å; Sn1—O2 = 2.121 (2) Å] and the Sn—Cl distances [Sn1—Cl1 = 2.3794 (9) Å; Sn1—Cl2 = 2.3667 (9) Å, Sn1—Cl3 = 2.3547 (9) Å and Sn1—Cl4 = 2.4407 (8) Å] (Table 1) are in good agreement with those of previously reported Sn—O and Sn—Cl bonds of related compounds (Willey et al.,1998; Skapski et al., 1974; Sow et al., 2010, 2013). The coordination sphere around the SnIV atom can be described as a slightly distorted octahedron with the O atoms of the oxalate ligand occupying equatorial cis-positions. The greatest deviation from the ideal octahedral geometry is manifested in the contraction of the Cl2—Sn1—Cl4 angle to 171.25 (3) °.

The stannate(IV) anion interacts with the two distinct cyclohexylammonium cations (both with chair conformation) through N—H···O and N—H···Cl hydrogen bonds (Table 2), leading to a two-dimensional network extending parallel to (100) (Fig. 2).

Related literature top

For applications of organotin(IV) compounds, see: Evans & Karpel (1985). For background to organotin(IV) chemistry, see: Ballmann et al. (2009); Meriem et al. (1989); Ng & Kumar Das (1997); Yin & Wang (2004); Zhang et al. (2006). For background to halogenidotin(IV) chemistry, see: Sarr & Diop (1990); Qamar-Kane & Diop (2010); Willey et al. (1998); Diallo et al. (2009). For related crystal structures with an oxalatotin(IV) moiety, see: Skapski et al. (1974); Gueye et al. (2012); Sow et al. (2010, 2013).

Experimental top

Chemicals were purchased from Sigma-Aldrich, and used without further purification. The title compound was obtained by reacting (C6H14N)2(C2O4).1.5H2O (0.09 g, 0.286 mmol) with SnCl2.2H2O (0,20 g, 0.890 mmol) in 25 ml of ethanol (96%). After slow solvent evaporation of the solvent at room temperature, colourless crystals suitable for X-ray diffraction analysis were obtained.

Refinement top

All H atoms, on carbon and nitrogen atoms, were placed at calculated positions using a riding model with C—H = 0.97 Å (methylene) or 0.98 Å (methine) and N—H = 0.89 Å with Uiso(H) = 1.2Ueq(C) and Uiso(H) = 1.5Ueq(N).

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2006); software used to prepare material for publication: WinGX (Farrugia, 2012).

Figures top
[Figure 1] Fig. 1. A view of the molecular entities of compound (I) with atom labelling. Displacement ellipsoids are draw at the 30% probability level.
[Figure 2] Fig. 2. The crystal packing of compound (I) viewed approximately along [100]. Hydrogen atoms are omitted for clarity. Intermolecular hydrogen-bonding interactions of the types N—H···O and O—H···O are shown by dotted lines. Displacement ellipsoids are draw at the 30% probability level. Colour code: Sn dark grey, O red, N blue, Cl green, C grey.
Bis(cyclohexylammonium) tetrachlorido(oxalato)stannate(IV) top
Crystal data top
(C6H14N)2[Sn(C2O4)Cl4]F(000) = 1104
Mr = 548.87Dx = 1.611 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 41791 reflections
a = 11.2293 (9) Åθ = 1.0–27.5°
b = 15.715 (1) ŵ = 1.62 mm1
c = 12.8464 (10) ÅT = 115 K
β = 93.238 (2)°Prism, colourless
V = 2263.4 (3) Å30.17 × 0.08 × 0.03 mm
Z = 4
Data collection top
Nonius KappaCCD
diffractometer
4979 independent reflections
Radiation source: fine-focus sealed tube4503 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.025
φ scans (κ = 0) + additional ω scansθmax = 27.5°, θmin = 2.7°
Absorption correction: multi-scan
(Blessing, 1995)
h = 1410
Tmin = 0.770, Tmax = 0.953k = 2012
9402 measured reflectionsl = 1616
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.035Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.083H-atom parameters constrained
S = 1.12 w = 1/[σ2(Fo2) + (0.0196P)2 + 5.6981P]
where P = (Fo2 + 2Fc2)/3
4979 reflections(Δ/σ)max = 0.001
228 parametersΔρmax = 1.03 e Å3
0 restraintsΔρmin = 0.99 e Å3
Crystal data top
(C6H14N)2[Sn(C2O4)Cl4]V = 2263.4 (3) Å3
Mr = 548.87Z = 4
Monoclinic, P21/cMo Kα radiation
a = 11.2293 (9) ŵ = 1.62 mm1
b = 15.715 (1) ÅT = 115 K
c = 12.8464 (10) Å0.17 × 0.08 × 0.03 mm
β = 93.238 (2)°
Data collection top
Nonius KappaCCD
diffractometer
4979 independent reflections
Absorption correction: multi-scan
(Blessing, 1995)
4503 reflections with I > 2σ(I)
Tmin = 0.770, Tmax = 0.953Rint = 0.025
9402 measured reflectionsθmax = 27.5°
Refinement top
R[F2 > 2σ(F2)] = 0.035H-atom parameters constrained
wR(F2) = 0.083Δρmax = 1.03 e Å3
S = 1.12Δρmin = 0.99 e Å3
4979 reflectionsAbsolute structure: ?
228 parametersAbsolute structure parameter: ?
0 restraintsRogers parameter: ?
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
Sn10.67656 (2)0.922515 (13)0.212827 (17)0.02314 (7)
C10.5332 (3)0.8427 (2)0.3693 (2)0.0240 (6)
C20.5332 (3)0.77851 (19)0.2768 (2)0.0222 (6)
O10.5778 (2)0.91628 (13)0.35167 (16)0.0231 (5)
O20.5826 (2)0.80588 (14)0.19492 (17)0.0248 (5)
O30.4905 (2)0.82201 (15)0.45140 (17)0.0326 (6)
O40.4875 (2)0.70888 (14)0.28564 (17)0.0282 (5)
Cl10.74421 (8)1.05949 (5)0.26855 (7)0.0349 (2)
Cl20.83254 (8)0.84828 (6)0.30516 (8)0.0403 (2)
Cl30.75536 (10)0.91018 (6)0.04748 (8)0.0428 (2)
Cl40.49591 (7)0.98965 (5)0.13685 (6)0.02334 (16)
N10.5547 (2)0.58436 (17)0.1384 (2)0.0254 (6)
H1A0.53440.61790.19040.038*
H1B0.50450.54060.13250.038*
H1C0.55150.61380.07920.038*
C30.6796 (3)0.5518 (2)0.1610 (3)0.0317 (7)
H30.67780.51290.22040.038*
C40.7205 (3)0.5014 (2)0.0690 (3)0.0305 (7)
H4A0.72080.53790.00810.037*
H4B0.66540.45500.05360.037*
C50.8453 (4)0.4659 (3)0.0929 (3)0.0397 (9)
H5A0.84350.42520.14960.048*
H5B0.87200.43650.03210.048*
C60.9310 (4)0.5365 (3)0.1229 (4)0.0478 (11)
H6A0.93880.57380.06360.057*
H6B1.00880.51240.14150.057*
C70.8886 (4)0.5888 (3)0.2157 (3)0.0439 (10)
H7A0.88930.55320.27740.053*
H7B0.94280.63600.22990.053*
C80.7630 (3)0.6227 (3)0.1914 (3)0.0418 (9)
H8A0.73520.65160.25220.050*
H8B0.76410.66370.13490.050*
N20.3881 (3)0.65674 (19)0.4780 (2)0.0357 (7)
H2A0.39400.64150.41180.054*
H2B0.42760.61970.51940.054*
H2C0.41910.70840.48800.054*
C90.2600 (3)0.6577 (2)0.5030 (3)0.0305 (7)
H90.22610.60120.48840.037*
C100.1935 (4)0.7220 (3)0.4339 (3)0.0507 (12)
H10A0.20130.70730.36130.061*
H10B0.22740.77810.44590.061*
C110.0621 (5)0.7226 (4)0.4580 (4)0.0613 (14)
H11A0.02080.76570.41570.074*
H11B0.02710.66790.43950.074*
C120.0451 (4)0.7404 (3)0.5710 (4)0.0463 (10)
H12A0.03880.73540.58410.056*
H12B0.06990.79830.58710.056*
C130.1164 (4)0.6793 (3)0.6413 (4)0.0460 (10)
H13A0.08360.62250.63260.055*
H13B0.10950.69600.71340.055*
C140.2475 (3)0.6780 (3)0.6171 (3)0.0357 (8)
H14A0.28310.73300.63330.043*
H14B0.28920.63550.65990.043*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Sn10.02712 (12)0.02014 (12)0.02230 (12)0.00106 (8)0.00262 (8)0.00254 (8)
C10.0337 (17)0.0208 (15)0.0172 (14)0.0033 (13)0.0001 (12)0.0019 (11)
C20.0309 (17)0.0183 (14)0.0176 (14)0.0010 (12)0.0023 (12)0.0001 (11)
O10.0344 (12)0.0175 (10)0.0173 (10)0.0006 (9)0.0015 (9)0.0013 (8)
O20.0372 (13)0.0199 (11)0.0180 (10)0.0011 (9)0.0073 (9)0.0024 (8)
O30.0566 (17)0.0251 (12)0.0170 (11)0.0004 (11)0.0104 (11)0.0013 (9)
O40.0425 (14)0.0202 (11)0.0227 (11)0.0028 (10)0.0078 (10)0.0031 (9)
Cl10.0358 (5)0.0249 (4)0.0430 (5)0.0060 (3)0.0077 (4)0.0024 (3)
Cl20.0355 (5)0.0359 (5)0.0487 (5)0.0104 (4)0.0055 (4)0.0070 (4)
Cl30.0523 (6)0.0416 (5)0.0369 (5)0.0105 (4)0.0239 (4)0.0083 (4)
Cl40.0294 (4)0.0237 (4)0.0168 (3)0.0014 (3)0.0000 (3)0.0001 (3)
N10.0298 (15)0.0261 (14)0.0206 (13)0.0021 (11)0.0031 (11)0.0023 (10)
C30.0303 (18)0.0380 (19)0.0271 (17)0.0054 (15)0.0022 (14)0.0047 (14)
C40.0336 (18)0.0315 (18)0.0265 (17)0.0019 (14)0.0022 (14)0.0053 (14)
C50.037 (2)0.039 (2)0.043 (2)0.0051 (17)0.0044 (17)0.0049 (17)
C60.034 (2)0.046 (2)0.063 (3)0.0009 (18)0.004 (2)0.015 (2)
C70.034 (2)0.049 (2)0.047 (2)0.0044 (18)0.0078 (18)0.0111 (19)
C80.038 (2)0.038 (2)0.049 (2)0.0018 (17)0.0006 (18)0.0200 (18)
N20.054 (2)0.0232 (14)0.0315 (15)0.0092 (13)0.0196 (14)0.0088 (12)
C90.042 (2)0.0235 (16)0.0261 (16)0.0048 (14)0.0021 (15)0.0010 (13)
C100.071 (3)0.057 (3)0.0249 (18)0.030 (2)0.0033 (19)0.0093 (18)
C110.059 (3)0.072 (3)0.051 (3)0.024 (3)0.022 (2)0.000 (2)
C120.038 (2)0.044 (2)0.058 (3)0.0096 (18)0.0054 (19)0.005 (2)
C130.042 (2)0.049 (2)0.048 (2)0.0089 (19)0.0129 (19)0.012 (2)
C140.039 (2)0.045 (2)0.0228 (17)0.0058 (17)0.0025 (15)0.0030 (15)
Geometric parameters (Å, º) top
Sn1—O22.121 (2)C7—C81.524 (6)
Sn1—O12.155 (2)C7—H7A0.9700
Sn1—Cl32.3547 (9)C7—H7B0.9700
Sn1—Cl22.3667 (9)C8—H8A0.9700
Sn1—Cl12.3794 (9)C8—H8B0.9700
Sn1—Cl42.4407 (8)N2—C91.491 (5)
C1—O31.227 (4)N2—H2A0.8900
C1—O11.286 (4)N2—H2B0.8900
C1—C21.559 (4)N2—H2C0.8900
C2—O41.217 (4)C9—C101.514 (5)
C2—O21.290 (4)C9—C141.514 (5)
N1—C31.505 (4)C9—H90.9800
N1—H1A0.8900C10—C111.524 (7)
N1—H1B0.8900C10—H10A0.9700
N1—H1C0.8900C10—H10B0.9700
C3—C81.493 (5)C11—C121.501 (7)
C3—C41.515 (5)C11—H11A0.9700
C3—H30.9800C11—H11B0.9700
C4—C51.524 (5)C12—C131.515 (6)
C4—H4A0.9700C12—H12A0.9700
C4—H4B0.9700C12—H12B0.9700
C5—C61.504 (6)C13—C141.521 (5)
C5—H5A0.9700C13—H13A0.9700
C5—H5B0.9700C13—H13B0.9700
C6—C71.544 (6)C14—H14A0.9700
C6—H6A0.9700C14—H14B0.9700
C6—H6B0.9700
O2—Sn1—O176.97 (8)C8—C7—H7A109.6
O2—Sn1—Cl392.35 (6)C6—C7—H7A109.6
O1—Sn1—Cl3168.53 (7)C8—C7—H7B109.6
O2—Sn1—Cl288.73 (7)C6—C7—H7B109.6
O1—Sn1—Cl287.92 (6)H7A—C7—H7B108.1
Cl3—Sn1—Cl296.10 (4)C3—C8—C7110.6 (3)
O2—Sn1—Cl1164.34 (6)C3—C8—H8A109.5
O1—Sn1—Cl187.86 (6)C7—C8—H8A109.5
Cl3—Sn1—Cl1102.47 (4)C3—C8—H8B109.5
Cl2—Sn1—Cl194.62 (3)C7—C8—H8B109.5
O2—Sn1—Cl486.17 (7)H8A—C8—H8B108.1
O1—Sn1—Cl484.01 (6)C9—N2—H2A109.5
Cl3—Sn1—Cl491.21 (3)C9—N2—H2B109.5
Cl2—Sn1—Cl4171.25 (3)H2A—N2—H2B109.5
Cl1—Sn1—Cl488.47 (3)C9—N2—H2C109.5
O3—C1—O1124.4 (3)H2A—N2—H2C109.5
O3—C1—C2120.1 (3)H2B—N2—H2C109.5
O1—C1—C2115.5 (3)N2—C9—C10109.3 (3)
O4—C2—O2125.4 (3)N2—C9—C14110.7 (3)
O4—C2—C1119.5 (3)C10—C9—C14110.9 (3)
O2—C2—C1115.1 (3)N2—C9—H9108.6
C1—O1—Sn1114.25 (19)C10—C9—H9108.6
C2—O2—Sn1115.71 (19)C14—C9—H9108.6
C3—N1—H1A109.5C9—C10—C11109.7 (4)
C3—N1—H1B109.5C9—C10—H10A109.7
H1A—N1—H1B109.5C11—C10—H10A109.7
C3—N1—H1C109.5C9—C10—H10B109.7
H1A—N1—H1C109.5C11—C10—H10B109.7
H1B—N1—H1C109.5H10A—C10—H10B108.2
C8—C3—N1111.1 (3)C12—C11—C10112.0 (4)
C8—C3—C4112.4 (3)C12—C11—H11A109.2
N1—C3—C4110.4 (3)C10—C11—H11A109.2
C8—C3—H3107.6C12—C11—H11B109.2
N1—C3—H3107.6C10—C11—H11B109.2
C4—C3—H3107.6H11A—C11—H11B107.9
C3—C4—C5110.5 (3)C11—C12—C13111.5 (4)
C3—C4—H4A109.6C11—C12—H12A109.3
C5—C4—H4A109.6C13—C12—H12A109.3
C3—C4—H4B109.6C11—C12—H12B109.3
C5—C4—H4B109.6C13—C12—H12B109.3
H4A—C4—H4B108.1H12A—C12—H12B108.0
C6—C5—C4110.4 (3)C12—C13—C14111.8 (3)
C6—C5—H5A109.6C12—C13—H13A109.3
C4—C5—H5A109.6C14—C13—H13A109.3
C6—C5—H5B109.6C12—C13—H13B109.3
C4—C5—H5B109.6C14—C13—H13B109.3
H5A—C5—H5B108.1H13A—C13—H13B107.9
C5—C6—C7111.7 (4)C9—C14—C13110.2 (3)
C5—C6—H6A109.3C9—C14—H14A109.6
C7—C6—H6A109.3C13—C14—H14A109.6
C5—C6—H6B109.3C9—C14—H14B109.6
C7—C6—H6B109.3C13—C14—H14B109.6
H6A—C6—H6B107.9H14A—C14—H14B108.1
C8—C7—C6110.5 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O40.891.972.853 (3)169
N1—H1B···O1i0.892.183.038 (4)163
N1—H1C···O3ii0.892.012.875 (4)162
N2—H2A···O40.892.252.887 (4)129
N2—H2A···Cl4i0.892.783.315 (3)120
N2—H2B···Cl4iii0.892.383.262 (3)169
N2—H2C···O30.892.022.869 (4)158
Symmetry codes: (i) x+1, y1/2, z+1/2; (ii) x, y+3/2, z1/2; (iii) x, y+3/2, z+1/2.
Selected bond lengths (Å) top
Sn1—O22.121 (2)Sn1—Cl22.3667 (9)
Sn1—O12.155 (2)Sn1—Cl12.3794 (9)
Sn1—Cl32.3547 (9)Sn1—Cl42.4407 (8)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O40.891.972.853 (3)169.4
N1—H1B···O1i0.892.183.038 (4)163.0
N1—H1C···O3ii0.892.012.875 (4)162.4
N2—H2A···O40.892.252.887 (4)128.8
N2—H2A···Cl4i0.892.783.315 (3)120.3
N2—H2B···Cl4iii0.892.383.262 (3)168.8
N2—H2C···O30.892.022.869 (4)158.2
Symmetry codes: (i) x+1, y1/2, z+1/2; (ii) x, y+3/2, z1/2; (iii) x, y+3/2, z+1/2.
Acknowledgements top

The authors gratefully acknowledge the Cheikh Anta Diop University of Dakar (Senegal), the Centre National de la Recherche Scientifique (CNRS, France) and the University of Burgundy (Dijon, France).

references
References top

Altomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl. Cryst. 26, 343–350.

Ballmann, J., Fuchs, M. G. G., Dechert, S., John, M. & Meyer, F. (2009). Inorg. Chem. 48, 90–99.

Blessing, R. H. (1995). Acta Cryst. A51, 33–38.

Diallo, W., Diassé-Sarr, A. D., Diop, L., Mahieu, B., Biesemans, M., Willem, R., Kociok-Köhn, G. & Molloy, K. C. (2009). St. Cerc. St. CICBIA, 10, 207–212.

Evans, C. J. & Karpel, S. (1985). Organotin Compounds in Modern Technology. J. Organomet. Chem. Library, Vol. 16. Amsterdam: Elsevier.

Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.

Gueye, N., Diop, L., Molloy, K. C. & Kociok-Köhn, G. (2012). Acta Cryst. E68, m854–m855.

Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457.

Meriem, A., Gielen, M. & Willem, R. (1989). J. Organomet. Chem. 365, 91–101.

Ng, S. W. & Kumar Das, V. G. (1997). Acta Cryst. C53, 1034–1036.

Nonius (1998). COLLECT. Nonius BV, Delft, The Netherlands.

Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press.

Qamar-Kane, H. & Diop, L. (2010). St. Cerc. St. CICBIA, 11, 389–392.

Sarr, O. & Diop, L. (1990). Spectrochim. Acta Part A, 46, 1239–1244.

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

Skapski, A. C., Guerchais, J.-E. & Calves, J.-Y. (1974). C. R. Acad. Sci. Ser. C Chim. 278, 1377–1379.

Sow, Y., Diop, L., Kociok-Köhn, G. & Molloy, K. C. (2010). Main Group Met. Chem. 33, 205–208.

Sow, Y., Diop, L., Molloy, K. C. & Kociok-Köhn, G. (2013). Acta Cryst. E69, m106–m107.

Willey, G. R., Woodman, T. J., Deeth, R. J. & Errington, W. (1998). Main Group Met. Chem. 21, 583–591.

Yin, H.-D. & Wang, C.-H. (2004). Appl. Organomet. Chem. 18, 411–412.

Zhang, W.-L., Ma, J.-F. & Jiang, H. (2006). Acta Cryst. E62, m460–m461.