Tri-μ-ethanethiol­ato-bis­{[η5-1,2,3,4-tetra­methyl-5-(trimethyl­silyl)cyclo­penta­dien­yl]iron(II,III)}(FeII–FeIII)

Jing Li

doi:10.1107/S1600536809045735

. 2009 Nov 7;65(Pt 12):m1542. doi: 10.1107/S1600536809045735

Tri-μ-ethanethiolato-bis{[η⁵-1,2,3,4-tetramethyl-5-(trimethylsilyl)cyclopentadienyl]iron(II,III)}(Fe^II–Fe^III)

Jing Li ^a,^*

PMCID: PMC2972053 PMID: 21578582

Abstract

The title complex, [Fe₂(C₂H₅S)₃(C₁₂H₂₁Si)₂], has an unusual Fe₂S₃ core. The two 1,2,3,4-tetramethyl-5-(trimethylsilyl)cyclopentadienyl (Cp′) ligands coordinate to the Fe atoms with their C₅ planes perpendicular [dihedral angles = 88.23 (7) and 88.55 (7)°] to the Fe—Fe vector, building two Cp′Fe subunits. These two subunits are bridged by three thiolate ligands. There are no significant differences in the coordination geometries between the two Fe atoms. The short Fe—Fe distance of 2.7842 (5) Å is clear evidence of an intermetallic bond. Such a diiron–sulfur structure might act as a model of active sites in some metalloproteins.

Related literature

For related diiron clusters, [CpFe(μ-SR)₃FeCp^*] (Cp = η⁵-C₅Me₅, R = Me, Et and Ph) and [CpFe(μ-SMe)₃FeCp], see: Chen et al. (2008a ▶,b ▶); Madec et al. (1999 ▶). graphic file with name e-65-m1542-scheme1.jpg

Experimental

Crystal data

[Fe₂(C₂H₅S)₃(C₁₂H₂₁Si)₂]
M _r = 681.82
Orthorhombic,
a = 17.7426 (19) Å
b = 19.874 (2) Å
c = 20.493 (2) Å
V = 7226.2 (13) Å³
Z = 8
Mo Kα radiation
μ = 1.06 mm⁻¹
T = 293 K
0.55 × 0.43 × 0.21 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.593, T _max = 0.808
43018 measured reflections
6541 independent reflections
4961 reflections with I > 2σ(I)
R _int = 0.055

Refinement

R[F ² > 2σ(F ²)] = 0.034
wR(F ²) = 0.095
S = 1.02
6541 reflections
334 parameters
H-atom parameters constrained
Δρ_max = 0.45 e Å⁻³
Δρ_min = −0.25 e Å⁻³

Data collection: SMART (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809045735/hy2242sup1.cif

e-65-m1542-sup1.cif^{(27.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809045735/hy2242Isup2.hkl

e-65-m1542-Isup2.hkl^{(320.2KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

Fe1—C13	2.104 (2)
Fe1—C14	2.111 (2)
Fe1—C15	2.126 (3)
Fe1—C16	2.136 (3)
Fe1—C17	2.123 (2)
Fe1—S1	2.2721 (7)
Fe1—S2	2.2765 (7)
Fe1—S3	2.2522 (7)
Fe2—C1	2.109 (2)
Fe2—C2	2.113 (2)
Fe2—C3	2.125 (2)
Fe2—C4	2.135 (2)
Fe2—C5	2.126 (2)
Fe2—S1	2.2659 (7)
Fe2—S2	2.2723 (7)
Fe2—S3	2.2545 (7)
Fe1—Fe2	2.7842 (5)

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Acknowledgments

The author is grateful for funding support (20060418) from Tianjin University of Science and Technology.

supplementary crystallographic information

Comment

As shown in Fig. 1, the title compound is a dimeric complex, in which each Fe atom is coordinated by a 1,2,3,4-tetramethyl-5-(trimethylsilyl)cyclopentadienyl (Cp') ligand and three ethanethiolate ligands. The C₅ planes of the two Cp' ligands are perpendicular to the Fe—Fe vector, with angles of 1.89 (7) and 1.45 (7)° between the normals of the planes and the vector. Three thiolate ligands bridge two Fe atoms (Table 1). The plane of the three S atoms is approximately parallel to the Cp' planes with dihedral angles of 1.77 (8) and 1.55 (8)°, respectively, and bisects the Fe—Fe bond. There are no significant differences in the coordination geometries between the two Fe centers. The short Fe—Fe distance of 2.7842 (5) Å is clear evidence of intermetallic bond.

Experimental

To a stirred suspension of Cp'Li (1.28 g, 6.38 mmol) in 50 ml THF was added anhydrous FeCl₂ (0.81 g, 6.38 mmol) at 0°C, followed by stirring for 1 h. The resultant olive-green [Cp'FeCl]₂ solution was cooled to -78°C. Then, a suspension of LiSEt in THF, which was prepared by reaction of n-BuLi (2.20 ml, 2.9 M solution in n-hexane) and HSEt (0.48 ml, 6.38 mmol) at 0°C, was transferred via a cannula to the cooled solution of [Cp'FeCl]₂. The mixture was placed in a -78°C bath for 1 h and stirred overnight as it warmed to ambient temperature. The resulting red-violet solution was evaporated to dryness, and the residue was purified by column chromatography on neutral alumina with n-hexane as the eluent to give complex [Cp'Fe(µ-SEt)₃FeCp'] (yield 0.42 g, 19%) as violet microcrystalline solid. The crystals of the title complex suitable for X-ray analysis were obtained from a benzene solution layered with acetonitrile.