metal-organic compounds
[μ-3-(Methylsulfanyl)benzene-1,2-dithiolato-1:2κ4S,S′:S,S′]bis[tricarbonyliron(I)]
aState Key Laboratory of Fine Chemicals, Dalian University of Technology (DUT), Dalian 116024, People's Republic of China, and bSchool of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, People's Republic of China
*Correspondence e-mail: ssdyok@yahoo.com.cn
The title compound, [Fe2(C7H6S3)(CO)6], was prepared as a biomimic for the active site of [FeFe]-hydrogenases. The central Fe2S2 core is in a butterfly conformation and each FeI atom has a pseudo-square-pyramidal coordination by three O atoms and two S atoms. The Fe—Fe distance is 2.471 (2) Å and the dihedral angle between the two Fe—S—Fe planes is 78.96 (7)°. The least-squares plane through the –S(C7H6S)S– bridge nearly bisects the molecular structure: except for the two Fe(CO)3 units, all atoms are in this plane with an average deviation from the plane of 0.028 (3) Å. In the crystal, the molecules are linked into chains along [001] by C—H⋯π(arene) interactions.
Related literature
For general background to [FeFe]-hydrogenases, see: Capon et al. (2009); Tard & Pickett (2009). For the of the natural enzyme, see: Peters et al. (1998); Nicolet et al. (1999). For related structures and the synthesis, see: Maiolo et al. (1981); Wang et al. (2005); Dong et al. (2006).
Experimental
Crystal data
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Data collection: APEX2 (Bruker, 2007); cell SAINT-Plus (Bruker, 2007); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.
Supporting information
https://doi.org/10.1107/S1600536813009860/vn2067sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536813009860/vn2067Isup2.hkl
All reactions and operations related to the title compound were carried out under a dry, prepurified nitrogen atmosphere with standard Schlenk techniques. All solvents were dried and distilled prior to use according to standard methods. The starting material 3-(methylthio)benzene-1,2-dilthiol was prepared by a similar procedure according to the literature (Maiolo et al., 1981). 3-(Methylthio)benzene-1,2-dilthiol (1 mmol, 0.188 g) and freshly synthesized Fe3(CO)12 (1 mmol, 0.503 g) were refluxed in toluene under N2 atmosphere for 3 h. The color of the solution changed gradually from dark green to dark red. The solvent was removed under reduced pressure. The residue was purified by ν(CO) 2075 (m), 2045 (s), 1999 (versus); 1H NMR (400 MHz, CDCl3): δ 6.92 (s, 1H, C6H3), 6.60 (s, 1H, C6H3), 6.53 (s, 1H, C6H3), 2.41 (s, 3H, SCH3).
on silica gel using hexane as to give the title compound as a red solid (0.294 g, 63%). A single-crystal suitable for X-ray study was obtained by slow evaporation of CH2Cl2/hexane (1:10, v/v) solution at room temperature. IR (CH2Cl2, cm-1):Hydrogen atoms were positioned geometrically and refined as riding atoms, with C–H = 0.93 (CH) and 0.96 (CH3) Å and with Uiso(H) = 1.2 (1.5 for methyl) Ueq(C).
[FeFe]-hydrogenases are important enzymes in numerous microorganisms, which can catalyse hydrogen evolution or uptake. Crystallographic and IR spectroscopic studies on the two types of [FeFe]Hases, CpI (Clostridium pasteurianum) and DdH (Desulfovibrio desulfuricans), revealed that the active site of [FeFe]-hydrogenases is comprised of a 2Fe2S butterfly structure, which contains diatomic ligands CO and CN-, a cysteinyl-S ligand connecting to a 4Fe4S subcluster, and a three-atom linker (–CH2XCH2–, X = CH2,NH or O) bridged between the two S atoms of the Fe2S2 H-cluster (Capon et al., 2009, Tard & Pickett, 2009). It was found that the introduction of a rigid and conjugate bridge to the Fe2S2 complexes could make the electrochemical properties of the complexes apparently different from the Fe2S2 complexes with flexible bridges (Capon et al., 2009).
The structure of the title compound resembles the active site of [FeFe]-hydrogenases, with a butterfly architectonic 2Fe2S core and the usual distorted square-pyramidal geometry around the iron center (Wang et al., 2005, Dong et al., 2006). The length of the Fe–Fe bond [2.471 (2) Å] is slightly shorter than those in the structures of natural enzymes (ca 2.6 Å) (Peters et al., 1998, Nicolet et al., 1999). The dihedral angle between two Fe–S–Fe planes is 78.96 (7) °. The rigid dithiolate bridge is a special feature for the title compound. The molecular structure has an internal pseudo-mirror plane passing through the aromatic ring. The calculated plane of the SRS bridge is nearly a bisecting plane of the molecular structure. Except for two Fe(CO)3 units all atoms are in the plane with the average deviation of 0.0280 Å. The deviations of the iron atoms from the SRS basal plane are 1.266 (5) Å for Fe(1) and 1.205 (5) Å for Fe(2). The molecular structure of the title compound is shown in Figure 1.
For general background to [FeFe]-hydrogenases, see: Capon et al. (2009); Tard & Pickett (2009). For the
of the natural enzyme, see: Peters et al. (1998); Nicolet et al. (1999). For related structures and the synthesis, see: Maiolo et al. (1981); Wang et al. (2005); Dong et al. (2006).Data collection: APEX2 (Bruker, 2007); cell
SAINT-Plus (Bruker, 2007); data reduction: SAINT-Plus (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).Fig. 1. Molecular structure of the title compound, with displacement ellipsoids drawn at the 30% probability level. |
[Fe2(C7H6S3)(CO)6] | F(000) = 928 |
Mr = 466.06 | Dx = 1.801 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 2629 reflections |
a = 16.531 (17) Å | θ = 2.5–27.1° |
b = 7.975 (8) Å | µ = 2.08 mm−1 |
c = 13.047 (13) Å | T = 295 K |
β = 92.055 (13)° | Block, red |
V = 1719 (3) Å3 | 0.39 × 0.24 × 0.08 mm |
Z = 4 |
Bruker APEXII CCD diffractometer | 3024 independent reflections |
Radiation source: fine-focus sealed tube | 2098 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.055 |
φ and ω scans | θmax = 25.0°, θmin = 2.5° |
Absorption correction: multi-scan (SADABS; Bruker, 2001) | h = −19→18 |
Tmin = 0.555, Tmax = 0.847 | k = −9→9 |
8260 measured reflections | l = −15→13 |
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)] = 0.036 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.084 | H-atom parameters constrained |
S = 0.97 | w = 1/[σ2(Fo2) + (0.0341P)2] where P = (Fo2 + 2Fc2)/3 |
3024 reflections | (Δ/σ)max < 0.001 |
217 parameters | Δρmax = 0.44 e Å−3 |
0 restraints | Δρmin = −0.31 e Å−3 |
[Fe2(C7H6S3)(CO)6] | V = 1719 (3) Å3 |
Mr = 466.06 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 16.531 (17) Å | µ = 2.08 mm−1 |
b = 7.975 (8) Å | T = 295 K |
c = 13.047 (13) Å | 0.39 × 0.24 × 0.08 mm |
β = 92.055 (13)° |
Bruker APEXII CCD diffractometer | 3024 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2001) | 2098 reflections with I > 2σ(I) |
Tmin = 0.555, Tmax = 0.847 | Rint = 0.055 |
8260 measured reflections |
R[F2 > 2σ(F2)] = 0.036 | 0 restraints |
wR(F2) = 0.084 | H-atom parameters constrained |
S = 0.97 | Δρmax = 0.44 e Å−3 |
3024 reflections | Δρmin = −0.31 e Å−3 |
217 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Fe1 | 0.17590 (2) | 0.29795 (7) | 0.64150 (4) | 0.04642 (17) | |
Fe2 | 0.18906 (3) | 0.54555 (7) | 0.52941 (4) | 0.04814 (18) | |
S3 | 0.46296 (5) | 0.53167 (12) | 0.73543 (7) | 0.0462 (2) | |
S2 | 0.22860 (5) | 0.28468 (12) | 0.48479 (7) | 0.0475 (2) | |
S1 | 0.27674 (5) | 0.48911 (12) | 0.66349 (7) | 0.0446 (2) | |
C8 | 0.35707 (16) | 0.3899 (4) | 0.5983 (2) | 0.0354 (7) | |
C10 | 0.3893 (2) | 0.2051 (4) | 0.4606 (3) | 0.0481 (9) | |
H10A | 0.3730 | 0.1375 | 0.4055 | 0.058* | |
C2 | 0.0831 (2) | 0.2118 (5) | 0.5909 (3) | 0.0560 (10) | |
C9 | 0.33421 (18) | 0.2915 (4) | 0.5159 (3) | 0.0401 (8) | |
C5 | 0.1075 (2) | 0.5260 (5) | 0.4373 (4) | 0.0605 (11) | |
C1 | 0.21760 (19) | 0.1120 (6) | 0.6991 (3) | 0.0564 (10) | |
C7 | 0.43793 (17) | 0.4062 (4) | 0.6280 (3) | 0.0377 (8) | |
C11 | 0.4698 (2) | 0.2221 (5) | 0.4897 (3) | 0.0514 (9) | |
H11A | 0.5086 | 0.1648 | 0.4535 | 0.062* | |
C12 | 0.49397 (19) | 0.3216 (4) | 0.5709 (3) | 0.0449 (9) | |
H12A | 0.5488 | 0.3324 | 0.5879 | 0.054* | |
O2 | 0.02428 (15) | 0.1593 (4) | 0.5570 (3) | 0.0859 (10) | |
O1 | 0.24308 (17) | −0.0076 (4) | 0.7338 (3) | 0.0867 (11) | |
C4 | 0.2506 (2) | 0.6882 (6) | 0.4606 (4) | 0.0700 (12) | |
O5 | 0.05695 (18) | 0.5075 (4) | 0.3771 (3) | 0.0918 (11) | |
O6 | 0.09707 (19) | 0.7802 (4) | 0.6518 (3) | 0.0961 (12) | |
O4 | 0.2905 (2) | 0.7821 (5) | 0.4201 (3) | 0.1088 (13) | |
O3 | 0.09360 (19) | 0.4359 (5) | 0.8164 (3) | 0.0994 (12) | |
C6 | 0.1338 (2) | 0.6903 (5) | 0.6042 (4) | 0.0643 (12) | |
C3 | 0.1254 (2) | 0.3805 (6) | 0.7494 (4) | 0.0631 (11) | |
C13 | 0.57037 (19) | 0.5072 (4) | 0.7506 (3) | 0.0543 (10) | |
H13A | 0.5900 | 0.5721 | 0.8082 | 0.082* | |
H13B | 0.5956 | 0.5454 | 0.6897 | 0.082* | |
H13C | 0.5831 | 0.3911 | 0.7619 | 0.082* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Fe1 | 0.0379 (3) | 0.0561 (4) | 0.0452 (3) | −0.0011 (2) | 0.0000 (2) | 0.0002 (3) |
Fe2 | 0.0429 (3) | 0.0491 (4) | 0.0522 (4) | 0.0050 (2) | −0.0029 (2) | −0.0011 (3) |
S3 | 0.0421 (4) | 0.0487 (6) | 0.0479 (6) | −0.0040 (4) | 0.0011 (4) | −0.0067 (5) |
S2 | 0.0480 (4) | 0.0519 (6) | 0.0422 (6) | −0.0004 (4) | −0.0046 (4) | −0.0077 (5) |
S1 | 0.0379 (4) | 0.0538 (6) | 0.0423 (6) | 0.0033 (4) | 0.0016 (4) | −0.0123 (4) |
C8 | 0.0392 (15) | 0.036 (2) | 0.0313 (19) | 0.0026 (15) | 0.0060 (13) | −0.0023 (16) |
C10 | 0.061 (2) | 0.046 (2) | 0.038 (2) | 0.0035 (18) | 0.0044 (17) | −0.0051 (18) |
C2 | 0.052 (2) | 0.058 (3) | 0.057 (3) | 0.0055 (19) | −0.0012 (18) | 0.002 (2) |
C9 | 0.0433 (16) | 0.040 (2) | 0.037 (2) | 0.0048 (15) | 0.0035 (14) | 0.0003 (17) |
C5 | 0.052 (2) | 0.061 (3) | 0.068 (3) | 0.0124 (19) | −0.001 (2) | −0.002 (2) |
C1 | 0.0372 (17) | 0.070 (3) | 0.061 (3) | −0.0023 (19) | −0.0012 (17) | −0.001 (2) |
C7 | 0.0405 (16) | 0.0300 (19) | 0.043 (2) | −0.0003 (14) | 0.0051 (14) | 0.0067 (16) |
C11 | 0.056 (2) | 0.050 (2) | 0.050 (3) | 0.0106 (18) | 0.0194 (17) | 0.003 (2) |
C12 | 0.0416 (17) | 0.046 (2) | 0.048 (2) | 0.0045 (16) | 0.0079 (15) | 0.0058 (19) |
O2 | 0.0549 (15) | 0.087 (2) | 0.115 (3) | −0.0205 (15) | −0.0156 (17) | −0.004 (2) |
O1 | 0.0665 (18) | 0.085 (2) | 0.108 (3) | 0.0094 (17) | −0.0127 (18) | 0.028 (2) |
C4 | 0.062 (2) | 0.069 (3) | 0.079 (3) | 0.006 (2) | −0.005 (2) | 0.006 (3) |
O5 | 0.0720 (19) | 0.109 (3) | 0.092 (3) | 0.0123 (17) | −0.034 (2) | −0.008 (2) |
O6 | 0.083 (2) | 0.088 (3) | 0.117 (3) | 0.0311 (18) | −0.0015 (19) | −0.043 (2) |
O4 | 0.101 (2) | 0.096 (3) | 0.130 (4) | −0.025 (2) | 0.021 (2) | 0.030 (3) |
O3 | 0.087 (2) | 0.145 (3) | 0.068 (3) | 0.028 (2) | 0.0250 (19) | −0.007 (2) |
C6 | 0.048 (2) | 0.064 (3) | 0.080 (3) | 0.004 (2) | −0.011 (2) | −0.005 (3) |
C3 | 0.0422 (19) | 0.087 (3) | 0.060 (3) | 0.005 (2) | 0.0038 (19) | 0.007 (3) |
C13 | 0.0432 (18) | 0.055 (3) | 0.064 (3) | −0.0049 (16) | −0.0044 (17) | −0.001 (2) |
Fe1—C1 | 1.789 (5) | C8—C9 | 1.373 (4) |
Fe1—C2 | 1.786 (4) | C10—C9 | 1.368 (5) |
Fe1—C3 | 1.788 (5) | C10—C11 | 1.378 (5) |
Fe1—Fe2 | 2.471 (2) | C10—H10A | 0.9300 |
Fe1—S1 | 2.2695 (19) | C11—C12 | 1.372 (5) |
Fe1—S2 | 2.253 (2) | C11—H11A | 0.9300 |
Fe2—C4 | 1.789 (5) | C12—H12A | 0.9300 |
Fe2—C5 | 1.781 (4) | C13—H13A | 0.9600 |
Fe2—C6 | 1.784 (5) | C13—H13B | 0.9600 |
Fe2—S1 | 2.2763 (19) | C13—H13C | 0.9600 |
Fe2—S2 | 2.263 (2) | O3—C3 | 1.127 (5) |
C1—O1 | 1.131 (4) | O6—C6 | 1.139 (5) |
C2—O2 | 1.133 (4) | S1—C8 | 1.787 (3) |
C4—O4 | 1.140 (5) | S2—C9 | 1.779 (3) |
C5—O5 | 1.135 (5) | S3—C7 | 1.759 (4) |
C7—C12 | 1.385 (5) | S3—C13 | 1.790 (4) |
C8—C7 | 1.385 (4) | ||
C2—Fe1—C3 | 90.77 (19) | C8—S1—Fe1 | 101.39 (13) |
C2—Fe1—C1 | 98.59 (17) | C8—S1—Fe2 | 100.67 (13) |
C3—Fe1—C1 | 99.1 (2) | Fe1—S1—Fe2 | 65.86 (5) |
C2—Fe1—S2 | 90.09 (15) | C9—C8—C7 | 120.6 (3) |
C3—Fe1—S2 | 159.76 (15) | C9—C8—S1 | 115.9 (2) |
C1—Fe1—S2 | 100.74 (14) | C7—C8—S1 | 123.4 (2) |
C2—Fe1—S1 | 157.30 (13) | C9—C10—C11 | 117.3 (3) |
C3—Fe1—S1 | 90.84 (14) | C9—C10—H10A | 121.3 |
C1—Fe1—S1 | 103.50 (13) | C11—C10—H10A | 121.3 |
S2—Fe1—S1 | 80.80 (5) | O2—C2—Fe1 | 178.5 (4) |
C2—Fe1—Fe2 | 100.45 (13) | C10—C9—C8 | 122.1 (3) |
C3—Fe1—Fe2 | 103.00 (16) | C10—C9—S2 | 122.0 (3) |
C1—Fe1—Fe2 | 150.44 (12) | C8—C9—S2 | 115.9 (2) |
S2—Fe1—Fe2 | 57.01 (5) | O5—C5—Fe2 | 177.1 (4) |
S1—Fe1—Fe2 | 57.20 (5) | O1—C1—Fe1 | 178.4 (4) |
C5—Fe2—C6 | 92.06 (19) | C8—C7—C12 | 117.4 (3) |
C5—Fe2—C4 | 98.5 (2) | C8—C7—S3 | 118.3 (2) |
C6—Fe2—C4 | 100.1 (2) | C12—C7—S3 | 124.3 (2) |
C5—Fe2—S2 | 87.98 (13) | C12—C11—C10 | 121.5 (3) |
C6—Fe2—S2 | 153.34 (15) | C12—C11—H11A | 119.3 |
C4—Fe2—S2 | 106.31 (16) | C10—C11—H11A | 119.3 |
C5—Fe2—S1 | 161.32 (14) | C11—C12—C7 | 121.0 (3) |
C6—Fe2—S1 | 91.81 (15) | C11—C12—H12A | 119.5 |
C4—Fe2—S1 | 98.82 (15) | C7—C12—H12A | 119.5 |
S2—Fe2—S1 | 80.45 (5) | O4—C4—Fe2 | 177.5 (5) |
C5—Fe2—Fe1 | 104.41 (14) | O6—C6—Fe2 | 178.4 (4) |
C6—Fe2—Fe1 | 97.78 (16) | O3—C3—Fe1 | 178.5 (5) |
C4—Fe2—Fe1 | 150.30 (13) | S3—C13—H13A | 109.5 |
S2—Fe2—Fe1 | 56.64 (3) | S3—C13—H13B | 109.5 |
S1—Fe2—Fe1 | 56.94 (5) | H13A—C13—H13B | 109.5 |
C7—S3—C13 | 103.30 (16) | S3—C13—H13C | 109.5 |
C9—S2—Fe1 | 101.52 (13) | H13A—C13—H13C | 109.5 |
C9—S2—Fe2 | 101.73 (12) | H13B—C13—H13C | 109.5 |
Fe1—S2—Fe2 | 66.35 (4) |
Cg1 is the centroid of the C7–C12 ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
C13—H13A···Cg1i | 0.96 | 2.69 | 3.590 (5) | 157 |
Symmetry code: (i) −x+1, y+1/2, −z+3/2. |
Experimental details
Crystal data | |
Chemical formula | [Fe2(C7H6S3)(CO)6] |
Mr | 466.06 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 295 |
a, b, c (Å) | 16.531 (17), 7.975 (8), 13.047 (13) |
β (°) | 92.055 (13) |
V (Å3) | 1719 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 2.08 |
Crystal size (mm) | 0.39 × 0.24 × 0.08 |
Data collection | |
Diffractometer | Bruker APEXII CCD |
Absorption correction | Multi-scan (SADABS; Bruker, 2001) |
Tmin, Tmax | 0.555, 0.847 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8260, 3024, 2098 |
Rint | 0.055 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.036, 0.084, 0.97 |
No. of reflections | 3024 |
No. of parameters | 217 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.44, −0.31 |
Computer programs: APEX2 (Bruker, 2007), SAINT-Plus (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
Fe1—C1 | 1.789 (5) | Fe2—C4 | 1.789 (5) |
Fe1—C2 | 1.786 (4) | Fe2—C5 | 1.781 (4) |
Fe1—C3 | 1.788 (5) | Fe2—C6 | 1.784 (5) |
Fe1—S1 | 2.2695 (19) | Fe2—S1 | 2.2763 (19) |
Fe1—S2 | 2.253 (2) | Fe2—S2 | 2.263 (2) |
Cg1 is the centroid of the C7–C12 ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
C13—H13A···Cg1i | 0.96 | 2.69 | 3.590 (5) | 157 |
Symmetry code: (i) −x+1, y+1/2, −z+3/2. |
Acknowledgements
We are grateful to the Chinese National Natural Science Foundation (grant No. 21101057), the Doctoral Fund of Henan University of Technology (No. 2009BS053) and the Science Foundation of the Education Department of Henan Province (No. 2011B150006) for support.
References
Bruker (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (2007). SAINT-Plus and APEX2. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Capon, J.-F., Gloaguen, F., Pétillon, F. Y., Schollhammer, P. & Talarmin, J. (2009). Coord. Chem. Rev. 253, 1476–1494. Web of Science CrossRef CAS Google Scholar
Dong, W., Wang, M., Liu, X., Jin, K., Li, G., Wang, F. & Sun, L. (2006). Chem. Commun. pp. 305–307. Web of Science CSD CrossRef Google Scholar
Maiolo, F., Testaferri, L., Tiecco, M. & Tingoli, M. (1981). J. Org. Chem. 46, 3070–3073. CrossRef CAS Web of Science Google Scholar
Nicolet, Y., Piras, C., Legrand, P., Hatchikian, C. E. & Fontecilla-Camps, J. C. (1999). Structure, 7, 13–23. Web of Science CrossRef PubMed CAS Google Scholar
Peters, J. W., Lanzilotta, W. N., Lemon, B. J. & Seefeldt, L. C. (1998). Science 282, 1853–1858. Web of Science CrossRef CAS PubMed Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Tard, C. & Pickett, C. J. (2009). Chem. Rev. 109, 2245–2274. Web of Science CrossRef PubMed CAS Google Scholar
Wang, F., Wang, M., Liu, X., Jin, K., Dong, W., Li, G., Åkermark, B. & Sun, L. (2005). Chem. Commun. pp. 3221–3223. Web of Science CSD CrossRef Google Scholar
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[FeFe]-hydrogenases are important enzymes in numerous microorganisms, which can catalyse hydrogen evolution or uptake. Crystallographic and IR spectroscopic studies on the two types of [FeFe]Hases, CpI (Clostridium pasteurianum) and DdH (Desulfovibrio desulfuricans), revealed that the active site of [FeFe]-hydrogenases is comprised of a 2Fe2S butterfly structure, which contains diatomic ligands CO and CN-, a cysteinyl-S ligand connecting to a 4Fe4S subcluster, and a three-atom linker (–CH2XCH2–, X = CH2,NH or O) bridged between the two S atoms of the Fe2S2 H-cluster (Capon et al., 2009, Tard & Pickett, 2009). It was found that the introduction of a rigid and conjugate bridge to the Fe2S2 complexes could make the electrochemical properties of the complexes apparently different from the Fe2S2 complexes with flexible bridges (Capon et al., 2009).
The structure of the title compound resembles the active site of [FeFe]-hydrogenases, with a butterfly architectonic 2Fe2S core and the usual distorted square-pyramidal geometry around the iron center (Wang et al., 2005, Dong et al., 2006). The length of the Fe–Fe bond [2.471 (2) Å] is slightly shorter than those in the structures of natural enzymes (ca 2.6 Å) (Peters et al., 1998, Nicolet et al., 1999). The dihedral angle between two Fe–S–Fe planes is 78.96 (7) °. The rigid dithiolate bridge is a special feature for the title compound. The molecular structure has an internal pseudo-mirror plane passing through the aromatic ring. The calculated plane of the SRS bridge is nearly a bisecting plane of the molecular structure. Except for two Fe(CO)3 units all atoms are in the plane with the average deviation of 0.0280 Å. The deviations of the iron atoms from the SRS basal plane are 1.266 (5) Å for Fe(1) and 1.205 (5) Å for Fe(2). The molecular structure of the title compound is shown in Figure 1.