{[μ,η²-Bis­(tri­methyl­stannyl)]­acetyl­ene}hexa­carbonyl­dicobalt

The structure of the title compound, [Co₂(C₈H₁₈Sn₂)(CO)₆], a distannyl-substituted dicobaltatetrahedrane, shows geo­metrical parameters noticeably different from those observed in the only monostannyl-substituted dicobaltatetrahedrane structurally studied so far. Thus, the complexed acetyl­enic bond in the title compound is shorter, and the cobalt–cobalt and cobalt–carbon bonds are longer, while the Sn—C—C angles are much smaller than in the complex with monostannyl-substituted ligand.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.034
• wR factor = 0.091
• Data-to-parameter ratio = 21.0

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



ABSTM_02  Alert C The ratio of expected to reported Tmax/Tmin(RR) is > 1.10
          Tmin and Tmax reported:      0.620     0.997
          Tmin and Tmax expected:      0.490     0.906
          RR =      1.149
          Please check that your absorption correction is appropriate.

PLAT_320  Alert C Check Hybridisation of  C(7)   in main residue          ?

PLAT_320  Alert C Check Hybridisation of  C(8)   in main residue          ?

General Notes



ABSTM_02  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      0.908
          Tmax scaled      0.906 Tmin scaled      0.563


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 3 Alert Level C = Please check

---

S1. Comment

The title compound (I) was prepared thirty years ago, but the nature of the bonding in the crystal remained unknown until now. The tin–carbon bond in stannyl alkynes is relatively labile, though these can be used in Stille-type palladium-catalysed cross-coupling reactions with organyl halides (Mitchell, 1998). However, the reactivity of the carbon–carbon triple bond is such that oligomeric and polymeric side-products are obtained in large amounts. Complexation of the carbon–carbon triple bond by the dicobalt hexacarbonyl moiety to give a dicobaltatetrahedrane structure does not hinder cross-coupling with activated organyl halides (Zavgorodnii et al., 2000). The title compound is air- and moisture-insensitive, whereas the uncomplexed bis(trimethylstannyl)acetylene is easily hydrolysed by atmospheric moisture.

Only one dicobaltatetrahedrane derived from a stannyl alkyne has so far been studied by X-ray crystallography (Wrackmeyer et al., 1997) but this compound (A) could be atypical for steric reasons, as it is prepared by reacting diphenyldiethynyltin Ph₂Sn(C≡CH)₂ with dicobalt octacarbonyl, both acetylenic bonds being converted to dicobaltatetrahedrane moieties.

The structure of (I) is shown in Fig. 1. The length of the complexed acetylenic triple bond in this structure is 1.309 (5) Å, as compared with 1.238 Å in the uncomplexed stannyl acetylene and 1.212 (1) Å in acetylene itself (Khaikin et al., 2000); it is markedly shorter than in (A) [1.322 (9) and 1.335 (9) Å]. The cobalt–cobalt distance (2.5043 (9) Å) is considerably longer than in (A) [2.4788 (2) and 2.487 (2) Å]. While in (A) the cobalt–carbon bond lengths in the dicobaltatetrahedrane moiety lie between 1.944 and 1.990 Å (the authors describe these as "normal" values), all four Co—C bonds in the title compound are equal or longer than 2.000 Å (up to 2.007 Å). The originally linear Sn—C—C—Sn arrangement is naturally considerably bent, the angles Sn—C—C being 144.7 (3)° and 145.7 (3)°; in (A), however, the bond angles are much larger at 150.5 (5) and 151.5 (5)°.

S2. Experimental

The compound was prepared in 66% yield as a dark red solid, decomposing at 373 K, according to the procedure described previously (Seyferth & White, 1971).

S3. Refinement

Hydrogen atoms were placed in calculated positions and included in the refinement in the riding motion approximation with U_iso constrained to be 1.5 times U_eq of the carrier atom for the methyl-H and 1.2 times U_eq for the remaining H atoms. The highest peak in the final difference map is at a distance of 0.84 Å from Sn2.

Computing details

Data collection: CAD4 Version 5.0 (Nonius, 1989); cell refinement: CAD4 Version 5.0 (Nonius, 1989); data reduction: XCAD4 (Harms, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL-Plus (Sheldrick, 1991); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997), PARST95 (Nardelli, 1995).

Figures

Fig. 1. : View of the title compound showing the labelling of all non-H atoms. Displacement ellipsoids are shown at the 30% probability level. H atoms are omitted for clarity.

(I)

Crystal data

[Co2(C8H18Sn2)(CO)6]	Z = 2
Mr = 637.52	F(000) = 608
Triclinic, P1	Dx = 1.942 Mg m^−3
a = 8.659 (4) Å	Ag Kα radiation, λ = 0.56083 Å
b = 10.0360 (17) Å	Cell parameters from 25 reflections
c = 13.292 (3) Å	θ = 12.1–15.4°
α = 91.731 (16)°	µ = 1.98 mm^−1
β = 91.17 (3)°	T = 293 K
γ = 109.09 (2)°	Plate, red-brown
V = 1090.5 (6) Å^3	0.40 × 0.30 × 0.05 mm

Data collection

Nonius CAD-4 diffractometer	3813 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.019
Graphite monochromator	θmax = 21.0°, θmin = 3.0°
ω/2θ scans	h = −11→11
Absorption correction: ψ scan (WinGX; Farrugia, 1999; North et al., 1968)	k = −12→12
Tmin = 0.620, Tmax = 0.997	l = −16→16
9426 measured reflections	3 standard reflections every 60 min
4713 independent reflections	intensity decay: none

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.034	H-atom parameters constrained
wR(F^2) = 0.091	w = 1/[σ^2(Fo^2) + (0.0639P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max = 0.002
4713 reflections	Δρmax = 1.15 e Å^−3
224 parameters	Δρmin = −1.54 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0075 (11)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Sn1	0.23433 (3)	0.46053 (3)	0.251823 (19)	0.04642 (10)
Sn2	0.54726 (3)	0.94962 (3)	0.21592 (2)	0.04575 (10)
Co1	0.09136 (6)	0.76295 (5)	0.17469 (4)	0.04472 (14)
Co2	0.16469 (6)	0.78922 (6)	0.35914 (4)	0.04702 (14)
O1	0.0671 (6)	1.0421 (4)	0.1399 (4)	0.1016 (13)
O2	−0.2450 (5)	0.5692 (5)	0.1871 (4)	0.1063 (15)
O3	0.1587 (6)	0.6853 (6)	−0.0283 (3)	0.1123 (15)
O4	−0.1387 (6)	0.5951 (6)	0.4359 (4)	0.126 (2)
O5	0.1589 (6)	1.0769 (4)	0.3971 (3)	0.1030 (14)
O6	0.3909 (6)	0.7805 (5)	0.5218 (3)	0.1100 (16)
C1	0.0780 (6)	0.9363 (5)	0.1549 (3)	0.0631 (11)
C2	−0.1150 (5)	0.6445 (5)	0.1830 (3)	0.0638 (11)
C3	0.1323 (6)	0.7160 (5)	0.0501 (3)	0.0666 (11)
C4	−0.0236 (7)	0.6703 (6)	0.4058 (4)	0.0759 (14)
C5	0.1607 (6)	0.9664 (5)	0.3817 (3)	0.0643 (11)
C6	0.3017 (6)	0.7841 (5)	0.4595 (3)	0.0662 (12)
C7	0.2264 (4)	0.6713 (4)	0.2535 (3)	0.0418 (7)
C8	0.3120 (4)	0.8039 (4)	0.2425 (3)	0.0412 (7)
C9	0.4148 (6)	0.4613 (6)	0.3624 (4)	0.0697 (12)
H9A	0.5213	0.5099	0.3381	0.105*
H9B	0.4066	0.3660	0.3762	0.105*
H9C	0.3980	0.5085	0.4231	0.105*
C10	0.3025 (8)	0.4188 (6)	0.1041 (4)	0.0757 (14)
H10A	0.4168	0.4682	0.0965	0.114*
H10B	0.2398	0.4500	0.0554	0.114*
H10C	0.2815	0.3192	0.0938	0.114*
C11	−0.0033 (6)	0.3260 (5)	0.2861 (4)	0.0756 (14)
H11A	0.0011	0.2343	0.3010	0.113*
H11B	−0.0765	0.3179	0.2293	0.113*
H11C	−0.0418	0.3650	0.3434	0.113*
C12	0.5244 (6)	1.1542 (4)	0.2171 (4)	0.0655 (11)
H12A	0.4192	1.1482	0.1890	0.098*
H12B	0.6085	1.2150	0.1777	0.098*
H12C	0.5351	1.1918	0.2851	0.098*
C13	0.7062 (6)	0.9255 (6)	0.3335 (4)	0.0750 (13)
H13A	0.6663	0.9439	0.3975	0.113*
H13B	0.8141	0.9907	0.3255	0.113*
H13C	0.7097	0.8308	0.3304	0.113*
C14	0.6169 (7)	0.8873 (7)	0.0737 (4)	0.0803 (15)
H14A	0.6323	0.7972	0.0786	0.120*
H14B	0.7171	0.9561	0.0547	0.120*
H14C	0.5326	0.8805	0.0239	0.120*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sn1	0.04805 (17)	0.04004 (15)	0.05211 (17)	0.01603 (11)	−0.00076 (11)	−0.00017 (10)
Sn2	0.03709 (15)	0.04657 (16)	0.05209 (16)	0.01188 (11)	0.00044 (10)	0.00039 (10)
Co1	0.0395 (3)	0.0487 (3)	0.0464 (3)	0.0152 (2)	−0.00260 (19)	0.0017 (2)
Co2	0.0472 (3)	0.0536 (3)	0.0437 (3)	0.0215 (2)	0.0020 (2)	−0.0023 (2)
O1	0.120 (4)	0.073 (2)	0.127 (4)	0.053 (3)	0.000 (3)	0.019 (2)
O2	0.052 (2)	0.123 (4)	0.116 (3)	−0.008 (2)	0.001 (2)	0.009 (3)
O3	0.129 (4)	0.156 (4)	0.054 (2)	0.052 (3)	0.002 (2)	−0.013 (2)
O4	0.085 (3)	0.158 (5)	0.101 (3)	−0.010 (3)	0.039 (3)	0.016 (3)
O5	0.136 (4)	0.078 (3)	0.113 (3)	0.063 (3)	−0.021 (3)	−0.028 (2)
O6	0.126 (4)	0.160 (5)	0.066 (2)	0.082 (3)	−0.028 (2)	−0.009 (3)
C1	0.058 (3)	0.070 (3)	0.067 (3)	0.029 (2)	−0.008 (2)	0.005 (2)
C2	0.046 (2)	0.075 (3)	0.064 (3)	0.012 (2)	−0.0060 (18)	0.002 (2)
C3	0.064 (3)	0.088 (3)	0.048 (2)	0.026 (2)	−0.0059 (19)	−0.004 (2)
C4	0.071 (3)	0.094 (4)	0.057 (3)	0.020 (3)	0.014 (2)	−0.003 (2)
C5	0.067 (3)	0.077 (3)	0.060 (2)	0.042 (2)	−0.007 (2)	−0.010 (2)
C6	0.080 (3)	0.083 (3)	0.044 (2)	0.040 (3)	−0.003 (2)	−0.0070 (19)
C7	0.0419 (18)	0.0432 (17)	0.0431 (17)	0.0182 (14)	0.0008 (13)	−0.0003 (13)
C8	0.0364 (16)	0.0440 (17)	0.0446 (18)	0.0153 (14)	−0.0009 (13)	0.0002 (14)
C9	0.069 (3)	0.078 (3)	0.071 (3)	0.038 (3)	−0.011 (2)	0.001 (2)
C10	0.096 (4)	0.076 (3)	0.063 (3)	0.040 (3)	0.008 (2)	−0.011 (2)
C11	0.061 (3)	0.057 (3)	0.096 (4)	0.002 (2)	0.002 (2)	0.010 (2)
C12	0.064 (3)	0.043 (2)	0.086 (3)	0.0130 (19)	−0.004 (2)	0.000 (2)
C13	0.055 (3)	0.090 (3)	0.080 (3)	0.024 (2)	−0.017 (2)	0.007 (3)
C14	0.081 (4)	0.101 (4)	0.064 (3)	0.038 (3)	0.015 (3)	−0.007 (3)

Geometric parameters (Å, º)

Sn1—C9	2.121 (5)	O4—C4	1.125 (6)
Sn1—C11	2.127 (5)	O5—C5	1.127 (6)
Sn1—C10	2.131 (5)	O6—C6	1.130 (6)
Sn1—C7	2.138 (3)	C7—C8	1.309 (5)
Sn2—C12	2.126 (4)	C9—H9A	0.9600
Sn2—C8	2.127 (4)	C9—H9B	0.9600
Sn2—C13	2.133 (5)	C9—H9C	0.9600
Sn2—C14	2.133 (5)	C10—H10A	0.9600
Co1—C3	1.781 (5)	C10—H10B	0.9600
Co1—C2	1.801 (5)	C10—H10C	0.9600
Co1—C1	1.808 (5)	C11—H11A	0.9600
Co1—C7	2.006 (4)	C11—H11B	0.9600
Co1—C8	2.006 (4)	C11—H11C	0.9600
Co1—Co2	2.5043 (9)	C12—H12A	0.9600
Co2—C6	1.780 (5)	C12—H12B	0.9600
Co2—C5	1.806 (5)	C12—H12C	0.9600
Co2—C4	1.811 (5)	C13—H13A	0.9600
Co2—C7	2.000 (3)	C13—H13B	0.9600
Co2—C8	2.007 (4)	C13—H13C	0.9600
O1—C1	1.119 (6)	C14—H14A	0.9600
O2—C2	1.136 (6)	C14—H14B	0.9600
O3—C3	1.127 (6)	C14—H14C	0.9600
C9—Sn1—C11	112.9 (2)	C8—C7—Co2	71.2 (2)
C9—Sn1—C10	112.0 (2)	C8—C7—Co1	71.0 (2)
C11—Sn1—C10	112.4 (2)	Co2—C7—Co1	77.38 (12)
C9—Sn1—C7	105.74 (17)	C8—C7—Sn1	144.7 (3)
C11—Sn1—C7	107.10 (18)	Co2—C7—Sn1	132.34 (18)
C10—Sn1—C7	106.14 (17)	Co1—C7—Sn1	132.51 (18)
C12—Sn2—C8	107.24 (17)	C7—C8—Co1	70.9 (2)
C12—Sn2—C13	113.1 (2)	C7—C8—Co2	70.7 (2)
C8—Sn2—C13	106.30 (17)	Co1—C8—Co2	77.22 (13)
C12—Sn2—C14	113.0 (2)	C7—C8—Sn2	145.7 (3)
C8—Sn2—C14	106.23 (19)	Co1—C8—Sn2	133.33 (18)
C13—Sn2—C14	110.5 (2)	Co2—C8—Sn2	130.94 (17)
C3—Co1—C2	99.2 (2)	Sn1—C9—H9A	109.5
C3—Co1—C1	100.1 (2)	Sn1—C9—H9B	109.5
C2—Co1—C1	106.8 (2)	H9A—C9—H9B	109.5
C3—Co1—C7	99.67 (19)	Sn1—C9—H9C	109.5
C2—Co1—C7	104.20 (19)	H9A—C9—H9C	109.5
C1—Co1—C7	139.71 (18)	H9B—C9—H9C	109.5
C3—Co1—C8	100.80 (19)	Sn1—C10—H10A	109.5
C2—Co1—C8	139.81 (18)	Sn1—C10—H10B	109.5
C1—Co1—C8	103.50 (18)	H10A—C10—H10B	109.5
C7—Co1—C8	38.10 (14)	Sn1—C10—H10C	109.5
C3—Co1—Co2	149.37 (16)	H10A—C10—H10C	109.5
C2—Co1—Co2	97.65 (15)	H10B—C10—H10C	109.5
C1—Co1—Co2	99.27 (15)	Sn1—C11—H11A	109.5
C7—Co1—Co2	51.21 (10)	Sn1—C11—H11B	109.5
C8—Co1—Co2	51.39 (10)	H11A—C11—H11B	109.5
C6—Co2—C5	99.0 (2)	Sn1—C11—H11C	109.5
C6—Co2—C4	99.5 (2)	H11A—C11—H11C	109.5
C5—Co2—C4	107.0 (3)	H11B—C11—H11C	109.5
C6—Co2—C7	100.43 (18)	Sn2—C12—H12A	109.5
C5—Co2—C7	140.47 (19)	Sn2—C12—H12B	109.5
C4—Co2—C7	103.3 (2)	H12A—C12—H12B	109.5
C6—Co2—C8	99.72 (19)	Sn2—C12—H12C	109.5
C5—Co2—C8	104.60 (19)	H12A—C12—H12C	109.5
C4—Co2—C8	139.60 (19)	H12B—C12—H12C	109.5
C7—Co2—C8	38.15 (14)	Sn2—C13—H13A	109.5
C6—Co2—Co1	149.34 (15)	Sn2—C13—H13B	109.5
C5—Co2—Co1	98.63 (15)	H13A—C13—H13B	109.5
C4—Co2—Co1	99.08 (17)	Sn2—C13—H13C	109.5
C7—Co2—Co1	51.41 (10)	H13A—C13—H13C	109.5
C8—Co2—Co1	51.39 (10)	H13B—C13—H13C	109.5
O1—C1—Co1	177.9 (5)	Sn2—C14—H14A	109.5
O2—C2—Co1	179.2 (5)	Sn2—C14—H14B	109.5
O3—C3—Co1	179.3 (5)	H14A—C14—H14B	109.5
O4—C4—Co2	178.6 (6)	Sn2—C14—H14C	109.5
O5—C5—Co2	179.0 (4)	H14A—C14—H14C	109.5
O6—C6—Co2	178.6 (5)	H14B—C14—H14C	109.5
C3—Co1—Co2—C6	6.1 (5)	C11—Sn1—C7—C8	179.0 (5)
C2—Co1—Co2—C6	129.0 (4)	C10—Sn1—C7—C8	−60.8 (5)
C1—Co1—Co2—C6	−122.5 (4)	C9—Sn1—C7—Co2	−63.9 (3)
C7—Co1—Co2—C6	26.9 (4)	C11—Sn1—C7—Co2	56.7 (3)
C8—Co1—Co2—C6	−22.5 (4)	C10—Sn1—C7—Co2	177.0 (3)
C3—Co1—Co2—C5	130.5 (4)	C9—Sn1—C7—Co1	−179.6 (2)
C2—Co1—Co2—C5	−106.6 (2)	C11—Sn1—C7—Co1	−59.0 (3)
C1—Co1—Co2—C5	1.9 (2)	C10—Sn1—C7—Co1	61.3 (3)
C7—Co1—Co2—C5	151.3 (2)	Co2—C7—C8—Co1	−82.72 (10)
C8—Co1—Co2—C5	101.8 (2)	Sn1—C7—C8—Co1	138.6 (4)
C3—Co1—Co2—C4	−120.6 (4)	Co1—C7—C8—Co2	82.72 (10)
C2—Co1—Co2—C4	2.3 (2)	Sn1—C7—C8—Co2	−138.6 (4)
C1—Co1—Co2—C4	110.8 (3)	Co2—C7—C8—Sn2	135.9 (5)
C7—Co1—Co2—C4	−99.8 (2)	Co1—C7—C8—Sn2	−141.4 (5)
C8—Co1—Co2—C4	−149.2 (2)	Sn1—C7—C8—Sn2	−2.8 (8)
C3—Co1—Co2—C7	−20.8 (3)	C3—Co1—C8—C7	−91.9 (3)
C2—Co1—Co2—C7	102.1 (2)	C2—Co1—C8—C7	26.6 (4)
C1—Co1—Co2—C7	−149.4 (2)	C1—Co1—C8—C7	164.9 (3)
C8—Co1—Co2—C7	−49.44 (18)	Co2—Co1—C8—C7	73.7 (2)
C3—Co1—Co2—C8	28.6 (4)	C3—Co1—C8—Co2	−165.62 (18)
C2—Co1—Co2—C8	151.5 (2)	C2—Co1—C8—Co2	−47.1 (3)
C1—Co1—Co2—C8	−99.9 (2)	C1—Co1—C8—Co2	91.17 (18)
C7—Co1—Co2—C8	49.44 (18)	C7—Co1—C8—Co2	−73.7 (2)
C6—Co2—C7—C8	−92.5 (3)	C3—Co1—C8—Sn2	59.2 (3)
C5—Co2—C7—C8	25.7 (4)	C2—Co1—C8—Sn2	177.7 (3)
C4—Co2—C7—C8	165.0 (3)	C1—Co1—C8—Sn2	−44.1 (3)
Co1—Co2—C7—C8	73.9 (2)	C7—Co1—C8—Sn2	151.1 (4)
C6—Co2—C7—Co1	−166.43 (19)	Co2—Co1—C8—Sn2	−135.2 (3)
C5—Co2—C7—Co1	−48.3 (3)	C6—Co2—C8—C7	94.6 (3)
C4—Co2—C7—Co1	91.1 (2)	C5—Co2—C8—C7	−163.5 (2)
C8—Co2—C7—Co1	−73.9 (2)	C4—Co2—C8—C7	−22.8 (4)
C6—Co2—C7—Sn1	56.4 (3)	Co1—Co2—C8—C7	−74.0 (2)
C5—Co2—C7—Sn1	174.6 (3)	C6—Co2—C8—Co1	168.56 (18)
C4—Co2—C7—Sn1	−46.0 (3)	C5—Co2—C8—Co1	−89.44 (17)
C8—Co2—C7—Sn1	148.9 (4)	C4—Co2—C8—Co1	51.2 (4)
Co1—Co2—C7—Sn1	−137.1 (3)	C7—Co2—C8—Co1	74.0 (2)
C3—Co1—C7—C8	95.2 (3)	C6—Co2—C8—Sn2	−54.1 (3)
C2—Co1—C7—C8	−162.6 (2)	C5—Co2—C8—Sn2	47.9 (3)
C1—Co1—C7—C8	−23.1 (4)	C4—Co2—C8—Sn2	−171.5 (3)
Co2—Co1—C7—C8	−74.2 (2)	C7—Co2—C8—Sn2	−148.7 (4)
C3—Co1—C7—Co2	169.41 (18)	Co1—Co2—C8—Sn2	137.3 (3)
C2—Co1—C7—Co2	−88.44 (18)	C12—Sn2—C8—C7	−179.1 (5)
C1—Co1—C7—Co2	51.1 (3)	C13—Sn2—C8—C7	−57.9 (5)
C8—Co1—C7—Co2	74.2 (2)	C14—Sn2—C8—C7	59.8 (5)
C3—Co1—C7—Sn1	−53.6 (3)	C12—Sn2—C8—Co1	55.0 (3)
C2—Co1—C7—Sn1	48.5 (3)	C13—Sn2—C8—Co1	176.3 (3)
C1—Co1—C7—Sn1	−172.0 (3)	C14—Sn2—C8—Co1	−66.0 (3)
C8—Co1—C7—Sn1	−148.8 (4)	C12—Sn2—C8—Co2	−59.5 (3)
Co2—Co1—C7—Sn1	137.0 (3)	C13—Sn2—C8—Co2	61.7 (3)
C9—Sn1—C7—C8	58.3 (5)	C14—Sn2—C8—Co2	179.4 (3)