CO Substitution Reactions of Diiron Complexes [{(μ‐SCH2)2X}Fe2(CO)6] and [{(μ‐SeCH2)2X}Fe2(CO)6] (X = O, CH2) with Ph2PCl/Me3NO to Give Ph2PCl‐, Ph2PNMe2‐, and Ph2PP(=O)Ph2‐Substituted Complexes Related to [FeFe] Hydrogenases. Issue 11 (24th February 2014) - Song, Li‐Cheng
Abstract: Diiron carbonyl complex [{(μ‐SCH2 )2 O}Fe2 (CO)6 ] (A ) reacted with Ph2 PCl and Me3 NO in MeCN at room temperature to give the expected and unexpected Ph2 PCl‐, Ph2 PNMe2 ‐, and Ph2 PP(=O)Ph2 ‐substituted complexes [{(μ‐SCH2 )2 O}Fe2 (CO)5 L] [1, L = Ph2 PCl;2, L = Ph2 PNMe2 ;3, L = Ph2 PP(=O)Ph2 ], whereas complex [{(μ‐SCH2 )2 CH2 }Fe2 (CO)6 ] (B ) reacted with Ph2 PCl and Me3 NO under similar conditions to afford only the unexpected complexes [{(μ‐SCH2 )2 CH2 }Fe2 (CO)5 L] [4, L = Ph2 PNMe2 ;5, L = Ph2 PP(=O)Ph2 ]. Similarly, complex [{(μ‐SeCH2 )2 O}Fe2 (CO)6 ] (C ) reacted with Ph2 PCl and Me3 NO in MeCN at room temperature to give the unexpected complexes [{(μ‐SeCH2 )2 O}Fe2 (CO)5 L] [6, L = Ph2 PNMe2 ;7, L = Ph2 PP(=O)Ph2 ], and the corresponding unexpected complexes [{(μ‐SeCH2 )2 CH2 }Fe2 (CO)5 L] [8, L = Ph2 PNMe2 ;9, L = Ph2 PP(=O)Ph2 ] were produced by the reaction of complex [{(μ‐SeCH2 )2 CH2 }Fe2 (CO)6 ] (D ) with Ph2 PCl and Me3 NO under similar conditions. The structures of1 –9 were characterized by elemental analysis and spectroscopy, and for1 –5 and7 –9 by X‐ray crystallography. Possible pathways for the formation of the functionalized phosphine‐substituted complexes1 –9 have been suggested. Complexes1 –9 can be regarded as models for [FeFe] hydrogenases as their structures are similar to the active site of [FeFe] hydrogenases, and some have been found to be catalysts for proton reduction to hydrogen in the presence of HOAc. Abstract : The functionalized phosphine‐substituted complexes1 –9 have been prepared by the reaction of [{(μ‐ECH2 )2 X}Fe2 (CO)6 ] (E = S, Se; X = O, CH2 ) with Ph2 PCl/Me3 NO. Some of these complexes have been found to be catalysts for proton reduction to H2 under CV conditions.