Reversible, Electrochemically Controlled Binding of Phosphine to Iron and Cobalt Bis(dithiolene) Complexes
详细信息 查看全文
- 作者：Rongmin Yu ; Kuppuswamy Arumugam ; Ashok Manepalli ; Yvon Tran ; Russell Schmehl ; Heiko Jacobsen ; James P. Donahue
- 刊名：Inorganic Chemistry
- 出版年：2007
- 出版时间：June 25, 2007
- 年：2007
- 卷：46
- 期：13
- 页码：5131 - 5133
- 全文大小：180K
- 年卷期：v.46,no.13(June 25, 2007)
- ISSN：1520-510X
文摘
The homoleptic bis(dithiolene) complexes [M(S2C2R2)2]2 (M = Fe,Co; R = p-anisyl) undergo two successive reductions to formanions that display [M(S2C2R2)2]22- 
2[M(S2C2R2)2]1- solutionequilibria. The neutral dimers react with Ph3P to form squarepyramidal [M(Ph3P)(S2C2R2)2]0. Voltammetric measurements upon[M(Ph3P)(S2C2R2)2]0 in CH2Cl2 reveal only irreversible features atnegative potentials, consistent with Ph3P dissociation upon reduction. Dissociation and reassociation of Ph3P from and to [Fe(Ph3P)(S2C2R2)2]0 is demonstrated by spectroelectrochemical measurements. These collective observations form the basis for a cycle ofreversible, electrochemically controlled binding of Ph3P to[M(S2C2R2)2]2 (M = Fe, Co; R = p-anisyl). All members of thecycle ([M(S2C2R2)2]20, [M(S2C2R2)2]21-, [M(S2C2R2)2]22-, [M(S2C2R2)2]1-,[M(Ph3P)(S2C2R2)2]) for M = Fe, Co have been characterized bycrystallography. Square planar [Fe(S2C2R2)2]1- is the first suchiron dithiolene species to be structurally identified and reveals Fe-Sbond distances of 2.172(1) and 2.179(1) Å, which are appreciablyshorter than those in corresponding square planar dianions.
2[M(S2C2R2)2]1- solutionequilibria. The neutral dimers react with Ph3P to form squarepyramidal [M(Ph3P)(S2C2R2)2]0. Voltammetric measurements upon[M(Ph3P)(S2C2R2)2]0 in CH2Cl2 reveal only irreversible features atnegative potentials, consistent with Ph3P dissociation upon reduction. Dissociation and reassociation of Ph3P from and to [Fe(Ph3P)(S2C2R2)2]0 is demonstrated by spectroelectrochemical measurements. These collective observations form the basis for a cycle ofreversible, electrochemically controlled binding of Ph3P to[M(S2C2R2)2]2 (M = Fe, Co; R = p-anisyl). All members of thecycle ([M(S2C2R2)2]20, [M(S2C2R2)2]21-, [M(S2C2R2)2]22-, [M(S2C2R2)2]1-,[M(Ph3P)(S2C2R2)2]) for M = Fe, Co have been characterized bycrystallography. Square planar [Fe(S2C2R2)2]1- is the first suchiron dithiolene species to be structurally identified and reveals Fe-Sbond distances of 2.172(1) and 2.179(1) Å, which are appreciablyshorter than those in corresponding square planar dianions.