Ligand effects on the electrochemical behavior of [Fe2(CO)5(L){μ-(SCH2)2(Ph)P<img border='0' src='http://www.rsc.org/images/entities/h2_char_e001.gif' alt='[double bond, length as m-dash]'/>O}] (L = PPh3, P(OEt)3) hydrogenase model complexes - Université de Bretagne Occidentale
Article Dans Une Revue Dalton Transactions Année : 2015

Ligand effects on the electrochemical behavior of [Fe2(CO)5(L){μ-(SCH2)2(Ph)P[double bond, length as m-dash]O}] (L = PPh3, P(OEt)3) hydrogenase model complexes

Résumé

In this paper we study the influence of substituting one CO ligand in [Fe2(CO)6{μ-(SCH2)2(Ph)P[double bond, length as m-dash]O}] (1) by better σ-donor L ligands affording [Fe2(CO)5(L){μ-(SCH2)2(Ph)P[double bond, length as m-dash]O}] {L = PPh3 (2) and P(OEt)3 (3)} in relation to the steric interactions and the voltammetric behavior. Cyclic voltammetric investigations under N2 and CO showed remarkable differences in the electrochemical behaviour of complexes 2 and 3: (i) Complex 2 tends to expel PPh3 upon reduction whereas complex 3 exhibits chemical reversibility and (ii) Under CO, complex 3 reacts with CO affording a new compound P, which shows a reversible wave at E1/2 ∼ −0.9 V (vs. ferrocenium/ferrocene couple). The presence of CO assists the formation of 1 after electrochemically induced loss of PPh3 during the voltammetric experiment of 2. Using DFT calculations we provide an explanation for the difference in stabilities between the Fe–PPh3 and Fe–P(OEt)3 bonds.

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Dates et versions

hal-01538592 , version 1 (13-06-2017)

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Laith R. Almazahreh, Wolfgang Imhof, Jean Talarmin, Philippe P. Schollhammer, Helmar Gorls, et al.. Ligand effects on the electrochemical behavior of [Fe2(CO)5(L){μ-(SCH2)2(Ph)P[double bond, length as m-dash]O}] (L = PPh3, P(OEt)3) hydrogenase model complexes . Dalton Transactions, 2015, 44 (16), pp.7177 - 7189. ⟨10.1039/C5DT00064E⟩. ⟨hal-01538592⟩
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