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Bubbling acetyl­ene gas slowly through a methanol solution of [(CO)6Fe2{μ-SSe}] containing sodium acetate for 48 h at room temperature yields the double-butterfly complex μ-[ethane-1,1,2,2-tetra(selenido/sulfido)]bis[hexacarbonyldiiron(FeFe)], [Fe4(C2H2S2Se2)(CO)12]. The molecular structure was established by single-crystal X-ray diffraction techniques. The structure consists of two Fe2SSe butterfly units linked to each other through a bridging HC—CH group. The mol­ecule has twofold symmetry and the two Fe atoms have distorted octahedral geometries.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100001037/da1109sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270100001037/da1109Isup2.hkl
Contains datablock I

Comment top

Bonding and reactivity studies of alkynes attached to metal centres is of considerable interest because of the potential of the coordinated alkynes to be transformed into useful organic species (Katz & Hacker, 1985). In contrast to the large number of reports on the different bonding modes between alkynes and transition metals (Sappa et al., 1985), studies of complexes in which alkynes are attached to main group elements are more recent and relatively few (Mathur, 1997). Recent successes in the area of incorporating group-16 elements into transition metal carbonyl complexes has evoked interest in studying the interaction of alkynes with these ligands. The facile addition of phenylacetylene to (CO)6Fe2(µ-Se2) and (CO)6Fe2(µ-EE') occurs at room temperature to form (CO)6Fe2{µ-SeC(H)=C(Ph)Se} and (CO)6Fe2{µ-EC(H) C(Ph)E'} respectively, whereas (CO)6Fe2(µ-S2) and (CO)6Fe2(µ-Te2) are inert towards such addition under similar reaction conditions (Mathur, Hossain et al., 1995). In (CO)6Fe2{µ-SeC(H)C(Ph)Se} the reactive Se sites are blocked, and addition of Pt(PPh3)2 (Mathur, Hossain, Das & Sinha et al., 1993) and (CO)6Fe2(µ-Se2) (Mathur & Hossain, 1993) occurs readily across the C=C bond to yield products in which the acetylenic bond is reduced. Similarly, addition of organometallic groups across the Fe—Fe bond can be carried out thermolytically, as in the formation of Se-bridged mixed-metal clusters Cp2Mo2Fe2(CO)64-Se)(µ3-Se)2 (Mathur, Hossain & Rheingold, 1993). Here we report the structural characterization of a mixed-chalcogenide double butterfly complex, (I), obtained from the reaction of (CO)6Fe2(µ-SSe) with acetylene. The starting material provides an important probe to the active metallic centre in enzymatic processes (Pombeiro & Richards, 1990) \sch

In this structure the Se and S positions are disordered with equal occupany (50%). The molecule contains a twofold axis bisecting the C7—C7' bond. The structure can be described as two Fe2SSe core units linked to each other through a bridging HC—CH group. As a result of the acetylene addition to the Fe2SSe tetrahedron, the acetylenic bond is reduced to beyond an olefinic bond order. The C7—C7' bond distance of 1.511 (16) Å in [{(CO)6Fe2SSe}2{µ-C(H)—C(H)}] is similar to that observed in [{(CO)6Fe2SSe}2{µ-C(H)—C(Ph)}] (1.53 (1) Å) (Mathur, Dash et al., 1996), whereas it is longer than the corresponding bond lengths of 1.48 (1) Å in [{(CO)6Fe2Se2}2{µ-C(H)—C(Ph)}] (Mathur & Hossain, 1993), 1.47 (1) Å in (CO)6Fe2{µ-Te(CH2)2Te} (Shieh & Shieh, 1994), 1.494 Å in (CO)6Fe2{µ-Se(CH2)2Se} (Mathur, Manimaran et al., 1996) and 1.42 (1) Å in [(CO)6Fe2{µ-SeC(H)—C(Ph)}Pt(PPh3)2] (Mathur, Hossain & Rheingold, 1993). Each Fe atom has three CO groups bonded to it. The CO groups, the µ3-S ligand, the µ3-Se ligand and the Fe—Fe bond define a distorted octahedral geometry around each Fe centre.

Experimental top

In a typical procedure, acetylene gas was bubbled at a slow rate with constant stirring into a methanol solution (15 ml) containing freshly prepared (CO)6Fe2(µ-SSe) (0.6 g, 1.53 mmol) (Mathur, Sekar et al., 1995) and anhydrous sodium acetate (0.25 g). The reaction was monitored by thin layer chromatography (TLC) and terminated after 48 h at room temperature, when all the (CO)6Fe2(µ-SSe) had been consumed. Chromatographic work up on silica gel TLC plates using 2:3 solution mixture of CH2Cl2:hexane yielded an orange band of [{(CO)6Fe2SSe}2{µ-C(H)—C(H)}] in 28% yield. Rectangular-shaped air-stable crystals of [{(CO)6Fe2SSe}2{µ-C(H)—C(H)}] were obtained by slow evaporation from a mixture of CH2Cl2/hexane solutions at 263 K. IR data: (ν, CH2Cl2) 2080(s), 2068 (s), 2042 (s), 2009 (s), 1997 (m) cm-1.

Refinement top

The data were originally collected in the monoclinic system and the structure solved in space group Cc. Additional symmetry was observed, and the structure was found to transform to the orthorhombic system, space group Fdd2. The Se and S positions were found to be disordered, so their occupancies were fixed at 50% and they were constrained to have the same positional coordinates and the same anisotropic thermal parameters. The hydrogen atom was fixed geometrically and not refined. During refinement, the structure was treated as a racemic twin. The occupancy of the major component refined to a value of 0.515.

Computing details top

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: NRCVAX (Gabe et al., 1989); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: NRCVAX; software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The structure of the title compound showing 30% probability displacement ellipsoids.
(I) top
Crystal data top
[Fe4(C2H2S2Se2)(CO)12]Dx = 2.262 Mg m3
Mr = 807.60Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Fdd2Cell parameters from 25 reflections
a = 6.531 (2) Åθ = 8.0–12.2°
b = 44.759 (4) ŵ = 5.70 mm1
c = 16.224 (2) ÅT = 293 K
V = 4742.6 (16) Å3Rectangular, orange
Z = 80.38 × 0.13 × 0.13 mm
F(000) = 3088
Data collection top
Enraf-Nonius CAD4
diffractometer
2188 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.034
Graphite monochromatorθmax = 27.4°, θmin = 1.8°
ω/2θ scansh = 80
Absorption correction: ψ scan
(North et al., 1968)
k = 1858
Tmin = 0.323, Tmax = 0.488l = 1921
6094 measured reflections3 standard reflections every 60 min
2449 independent reflections intensity decay: 2%
Refinement top
Refinement on F2Primary atom site location: heavy-atom
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.037Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.108H-atom parameters constrained
S = 1.10 w = 1/[σ2(Fo2) + (0.0473P)2 + 78.9306P]
where P = (Fo2 + 2Fc2)/3
2449 reflections(Δ/σ)max = 0.001
154 parametersΔρmax = 0.48 e Å3
1 restraintΔρmin = 0.48 e Å3
Crystal data top
[Fe4(C2H2S2Se2)(CO)12]V = 4742.6 (16) Å3
Mr = 807.60Z = 8
Orthorhombic, Fdd2Mo Kα radiation
a = 6.531 (2) ŵ = 5.70 mm1
b = 44.759 (4) ÅT = 293 K
c = 16.224 (2) Å0.38 × 0.13 × 0.13 mm
Data collection top
Enraf-Nonius CAD4
diffractometer
2188 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.034
Tmin = 0.323, Tmax = 0.4883 standard reflections every 60 min
6094 measured reflections intensity decay: 2%
2449 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0371 restraint
wR(F2) = 0.108H-atom parameters constrained
S = 1.10 w = 1/[σ2(Fo2) + (0.0473P)2 + 78.9306P]
where P = (Fo2 + 2Fc2)/3
2449 reflectionsΔρmax = 0.48 e Å3
154 parametersΔρmin = 0.48 e Å3
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Se10.54003 (17)0.77886 (2)0.05105 (7)0.0334 (3)0.5
Se20.08860 (15)0.78785 (2)0.00076 (6)0.0239 (2)0.5
Fe10.32371 (18)0.82009 (2)0.06395 (7)0.0337 (3)
Fe20.39615 (17)0.79592 (2)0.07283 (7)0.0306 (2)
S10.54003 (17)0.77886 (2)0.05105 (7)0.0334 (3)0.5
S20.08860 (15)0.78785 (2)0.00076 (6)0.0239 (2)0.5
O10.0963 (14)0.87131 (13)0.0035 (6)0.073 (2)
O20.1397 (18)0.8162 (2)0.2256 (5)0.100 (4)
O30.6805 (14)0.85641 (19)0.1043 (6)0.082 (3)
O40.5112 (14)0.75006 (18)0.1933 (6)0.072 (2)
O50.7465 (11)0.83563 (18)0.0979 (5)0.066 (2)
O60.1609 (13)0.8288 (2)0.1983 (6)0.081 (3)
C10.1892 (16)0.8520 (2)0.0235 (7)0.049 (2)
C20.2155 (19)0.8180 (2)0.1636 (7)0.061 (3)
C30.5412 (17)0.84249 (19)0.0872 (7)0.053 (2)
C40.4660 (15)0.76641 (18)0.1451 (6)0.044 (2)
C50.6128 (14)0.82003 (18)0.0883 (6)0.0412 (19)
C60.2509 (15)0.8162 (2)0.1493 (6)0.046 (2)
C70.3620 (12)0.74577 (16)0.0727 (5)0.0324 (16)
H70.39370.73900.12870.050*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Se10.0312 (5)0.0293 (5)0.0396 (6)0.0041 (4)0.0032 (5)0.0054 (4)
Se20.0233 (4)0.0202 (4)0.0282 (5)0.0021 (4)0.0028 (4)0.0017 (4)
Fe10.0424 (6)0.0280 (5)0.0308 (5)0.0075 (4)0.0071 (5)0.0025 (4)
Fe20.0316 (5)0.0319 (5)0.0283 (5)0.0009 (4)0.0065 (5)0.0023 (4)
S10.0312 (5)0.0293 (5)0.0396 (6)0.0041 (4)0.0032 (5)0.0054 (4)
S20.0233 (4)0.0202 (4)0.0282 (5)0.0021 (4)0.0028 (4)0.0017 (4)
O10.090 (5)0.031 (3)0.097 (6)0.011 (4)0.001 (5)0.006 (4)
O20.137 (9)0.116 (7)0.046 (5)0.058 (7)0.046 (6)0.023 (4)
O30.070 (6)0.079 (5)0.099 (7)0.044 (5)0.008 (5)0.018 (5)
O40.085 (5)0.065 (4)0.066 (5)0.000 (4)0.027 (5)0.020 (4)
O50.053 (4)0.085 (5)0.061 (5)0.023 (4)0.009 (4)0.017 (4)
O60.067 (5)0.111 (7)0.064 (6)0.017 (5)0.003 (5)0.042 (5)
C10.055 (5)0.038 (5)0.053 (5)0.008 (4)0.015 (4)0.006 (4)
C20.080 (8)0.058 (6)0.047 (6)0.036 (5)0.010 (6)0.011 (4)
C30.064 (6)0.037 (4)0.057 (6)0.012 (4)0.007 (5)0.005 (4)
C40.052 (5)0.041 (4)0.040 (5)0.006 (4)0.015 (4)0.005 (3)
C50.040 (4)0.044 (4)0.040 (5)0.000 (4)0.000 (4)0.011 (3)
C60.044 (5)0.050 (5)0.045 (5)0.001 (4)0.008 (4)0.004 (4)
C70.035 (4)0.032 (4)0.030 (4)0.000 (3)0.002 (3)0.003 (3)
Geometric parameters (Å, º) top
Se1/S1—C71.916 (7)Fe2—C61.805 (10)
Se1/S1—Fe12.334 (2)Fe2—C41.824 (8)
Se1/S1—Fe22.346 (2)O1—C11.145 (13)
Se2/S2—C7i1.931 (8)O2—C21.124 (13)
Se2/S2—Fe12.343 (1)O3—C31.137 (12)
Se2/S2—Fe22.364 (1)O4—C41.111 (11)
Fe1—C21.766 (11)O5—C51.128 (11)
Fe1—C31.779 (10)O6—C61.139 (12)
Fe1—C11.799 (11)C7—C7i1.511 (16)
Fe1—Fe22.514 (2)C7—H70.9800
Fe2—C51.797 (9)
C7—Se1/S1—Fe1103.2 (2)C5—Fe2—Se1/S190.0 (3)
C7—Se1/S1—Fe299.5 (2)C6—Fe2—Se1/S1164.2 (3)
Fe1—Se1/S1—Fe265.0 (1)C4—Fe2—Se1/S1102.4 (3)
C7i—Se2/S2—Fe196.1 (2)C5—Fe2—Se2/S2146.2 (3)
C7i—Se2/S2—Fe2106.4 (2)C6—Fe2—Se2/S288.7 (3)
Fe1—Se2/S2—Fe264.5 (1)C4—Fe2—Se2/S2115.2 (3)
C2—Fe1—C399.0 (5)Se1/S1—Fe2—Se2/S281.8 (1)
C2—Fe1—C1100.4 (5)C5—Fe2—Fe190.8 (3)
C3—Fe1—C191.2 (5)C6—Fe2—Fe1107.0 (3)
C2—Fe1—Se1/S1106.4 (4)C4—Fe2—Fe1157.8 (3)
C3—Fe1—Se1/S188.9 (3)Se1/S1—Fe2—Fe157.3 (1)
C1—Fe1—Se1/S1152.9 (3)Se2/S2—Fe2—Fe157.3 (1)
C2—Fe1—Se2/S296.0 (3)O1—C1—Fe1176.7 (10)
C3—Fe1—Se2/S2164.4 (3)O2—C2—Fe1177.3 (11)
C1—Fe1—Se2/S290.5 (3)O3—C3—Fe1178.0 (11)
Se1/S1—Fe1—Se2/S282.6 (1)O4—C4—Fe2174.8 (9)
C2—Fe1—Fe2149.3 (3)O5—C5—Fe2178.7 (9)
C3—Fe1—Fe2106.2 (3)O6—C6—Fe2179.1 (10)
C1—Fe1—Fe296.4 (3)C7i—C7—Se1/S1113.2 (6)
Se1/S1—Fe1—Fe257.8 (1)C7i—C7—Se2/S2i110.9 (5)
Se2/S2—Fe1—Fe258.1 (1)Se1/S1—C7—Se2/S2i113.0 (4)
C5—Fe2—C691.0 (4)C7i—C7—H7106.4
C5—Fe2—C498.5 (4)Se1/S1—C7—H7106.4
C6—Fe2—C493.0 (4)Se2/S2i—C7—H7106.4
Symmetry code: (i) x+1/2, y+3/2, z.

Experimental details

Crystal data
Chemical formula[Fe4(C2H2S2Se2)(CO)12]
Mr807.60
Crystal system, space groupOrthorhombic, Fdd2
Temperature (K)293
a, b, c (Å)6.531 (2), 44.759 (4), 16.224 (2)
V3)4742.6 (16)
Z8
Radiation typeMo Kα
µ (mm1)5.70
Crystal size (mm)0.38 × 0.13 × 0.13
Data collection
DiffractometerEnraf-Nonius CAD4
diffractometer
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.323, 0.488
No. of measured, independent and
observed [I > 2σ(I)] reflections
6094, 2449, 2188
Rint0.034
(sin θ/λ)max1)0.648
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.037, 0.108, 1.10
No. of reflections2449
No. of parameters154
No. of restraints1
H-atom treatmentH-atom parameters constrained
w = 1/[σ2(Fo2) + (0.0473P)2 + 78.9306P]
where P = (Fo2 + 2Fc2)/3
Δρmax, Δρmin (e Å3)0.48, 0.48

Computer programs: CAD-4 Software (Enraf-Nonius, 1989), CAD-4 Software, NRCVAX (Gabe et al., 1989), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), NRCVAX, SHELXL97.

Selected geometric parameters (Å, º) top
Se1/S1—C71.916 (7)Se2/S2—Fe12.343 (1)
Se1/S1—Fe12.334 (2)Se2/S2—Fe22.364 (1)
Se1/S1—Fe22.346 (2)Fe1—Fe22.514 (2)
Se2/S2—C7i1.931 (8)
C7—Se1/S1—Fe1103.2 (2)C1—Fe1—Fe296.4 (3)
C7—Se1/S1—Fe299.5 (2)Se1/S1—Fe1—Fe257.8 (1)
Fe1—Se1/S1—Fe265.0 (1)Se2/S2—Fe1—Fe258.1 (1)
C7i—Se2/S2—Fe196.1 (2)C5—Fe2—C691.0 (4)
C7i—Se2/S2—Fe2106.4 (2)C5—Fe2—C498.5 (4)
Fe1—Se2/S2—Fe264.5 (1)C6—Fe2—C493.0 (4)
C2—Fe1—C399.0 (5)C5—Fe2—Se1/S190.0 (3)
C2—Fe1—C1100.4 (5)C6—Fe2—Se1/S1164.2 (3)
C3—Fe1—C191.2 (5)C4—Fe2—Se1/S1102.4 (3)
C2—Fe1—Se1/S1106.4 (4)C5—Fe2—Se2/S2146.2 (3)
C3—Fe1—Se1/S188.9 (3)C6—Fe2—Se2/S288.7 (3)
C1—Fe1—Se1/S1152.9 (3)C4—Fe2—Se2/S2115.2 (3)
C2—Fe1—Se2/S296.0 (3)Se1/S1—Fe2—Se2/S281.8 (1)
C3—Fe1—Se2/S2164.4 (3)C5—Fe2—Fe190.8 (3)
C1—Fe1—Se2/S290.5 (3)C6—Fe2—Fe1107.0 (3)
Se1/S1—Fe1—Se2/S282.6 (1)C4—Fe2—Fe1157.8 (3)
C2—Fe1—Fe2149.3 (3)Se1/S1—Fe2—Fe157.3 (1)
C3—Fe1—Fe2106.2 (3)Se2/S2—Fe2—Fe157.3 (1)
Symmetry code: (i) x+1/2, y+3/2, z.
 

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