A Tetranuclear Propane-1,3-Dithiolate Complex, [Fe2(CO)5{Ph2P(CH2)3}{(µ-SCH2)2CH2}]2, with a Bridging 1,6-Bis(diphenylphosphino)hexane Ligand

The 2:1 molar reaction of [Fe₂(CO)₆{(µ-SCH₂)₂CH₂}] (1) and a bidentate diphosphine ligand, 1,6-bis(diphenylphosphino)hexane (dpph), in the presence of Me₃NO resulted in the isolation of [Fe₂(CO)₅{Ph₂P(CH₂)₃}{(µ-SCH₂)₂CH₂}]₂ (2) as red crystals in 71?% yield. The dpph ligand in compound 2, coordinates two Fe₂S₂ subunits as bridging mode and hence makes a linkage between two [Fe₂(CO)₅{(µ-SCH₂)₂CH₂}] fragments. Each Fe₂S₂ butterfly of the complex consists of two fused Fe(S-C-C-C-S) six-membered rings, one of which attains a chair conformation, and the other is necessarily in a boat conformation. Compound 2 has unequivocally been characterized by elemental analysis, IR, ¹H NMR and ³¹P NMR spectroscopy together with single crystal X-ray diffraction studies. Crystals of 2 are triclinic, space group P-1, a = 9.918(4) Å, b = 10.347(3) Å, c = 14.581(5) Å, α?=?72.239(12)º, β?=?80.342(12)º, γ?=?68.550(14)º and Z = 1.

Graphic Abstract

A novel tetranuclear propane-1,3-dithiolate complex, [Fe₂(CO)₅{Ph₂P(CH₂)₃}{(μ-SCH₂)₂CH₂}]₂ (2), bearing a bridging bis(diphenylphosphino)hexane (dpph) ligand, was synthesized from the Me₃NO aided room temperature displacement of carbonyls from [Fe₂(CO)₆{(μ-SCH₂)₂CH₂}] (1), and structurally characterized.

     

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