| 17511444 |
Yu R, Arumugam K, Manepalli A, Tran Y, Schmehl R, Jacobsen H, Donahue JP: Reversible, electrochemically controlled binding of phosphine to iron and cobalt bis (dithiolene) complexes. Inorg Chem. 2007 Jun 25;46(13):5131-3. Epub 2007 May 19.
The homoleptic bis (dithiolene) complexes [M (S (2) C (2) R (2))(2)](2) (M = Fe, Co; R = p-anisyl) undergo two successive reductions to form anions that display [M (S (2) C (2) R (2))(2)](2)(2-) <--> 2 [M (S (2) C (2) R (2))(2)](1-) solution equilibria. The neutral dimers react with Ph3P to form square pyramidal [M (Ph (3) P)(S (2) C (2) R (2))(2)](0). Voltammetric measurements upon [M (Ph (3) P)(S (2) C (2) R (2))(2)](0) in CH (2) Cl (2) reveal only irreversible features at negative potentials, consistent with Ph (3) P dissociation upon reduction. Dissociation and reassociation of Ph (3) P from and to [Fe (Ph (3) P)(S (2) C (2) R (2))(2)](0) is demonstrated by spectroelectrochemical measurements. These collective observations form the basis for a cycle of reversible, electrochemically controlled binding of Ph (3) P to [M (S (2) C (2) R (2))(2)](2) (M = Fe, Co; R = p-anisyl). All members of the cycle ([M (S (2) C (2) R (2))(2)](2)(0), [M (S (2) C (2) R (2))(2)](2)(1-), [MM (S (2) C (2) R (2))(2)](2)(2-), [M (S (2) C (2) R (2))(2)](1-), [M (Ph (3) P)(S (2) C (2) R (2))(2)]) for M = Fe, Co have been characterized by crystallography. Square planar [Fe (S (2) C (2) R (2))(2)](1-) is the first such iron dithiolene species to be structurally identified and reveals Fe-S bond distances of 2.172 (1) and 2.179 (1) Angstrom, which are appreciably shorter than those in corresponding square planar dianions. |
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