The synthesis and full characterization of several transition metal complexes of a redox-switchable,biaryl(Ar^(T))-substituted[1]phosphaferrocenophane,FcPAr^(T)(L2),in conjunction with some palladium complexes of the ...The synthesis and full characterization of several transition metal complexes of a redox-switchable,biaryl(Ar^(T))-substituted[1]phosphaferrocenophane,FcPAr^(T)(L2),in conjunction with some palladium complexes of the mesityl(Mes)-substituted derivative,FcPMes(L1),and the non-bridged diphenylferrocenyl phosphine,Ph_(2)PFc(L3),are reported.Cyclic voltammetry studies on the bimetallic complexes[Ir(κ^(1)P-L2)(cod)Cl](1),[Ir(κ^(1)P-L2)(CO)2Cl](2),[AuCl(κ^(1)P-L2)](3),[Pd(κ^(1)P-L2)(η^(3)-allyl)Cl](4),[Pd(κ^(1)P-L3)(η^(3)-allyl)Cl](5),[Pd(κ^(1)P-L3)(2-aminobiphenyl)(SO_(3)CH_(3))](6),and[Pd(κ^(1)P-L1)(2-aminobiphenyl)(SO_(3)CH_(3))](7)provided indications for a good electronic communication between the metal atoms.In order to confirm that the[1]ferrocenophane or 1-ferrocenyl unit might be able to electrochemically influence the reactivity of the coordinated transition metal,the palladium complexes 4-7 were employed as redox-switchable catalysts(RSC)in Buchwald-Hartwig cross-coupling reactions.The catalytic activity depends on the ligand and decreases in the series L3>L2>L1.In stirred solutions,the reaction rate can be influenced by addition of an oxidizing reagent.Some reactions were accelerated with in situ generated,cationic complexes as catalysts as compared to their neutral analogs;in some cases,the activity was found to be lower.Furthermore,steric effects play a predominant role,among other factors.展开更多
基金financial support from the DFG-funded transregional collaborative research centre SFB/TRR 88“Cooperative effects in homo-and heterometallic complexes(3MET)”(project B4).
文摘The synthesis and full characterization of several transition metal complexes of a redox-switchable,biaryl(Ar^(T))-substituted[1]phosphaferrocenophane,FcPAr^(T)(L2),in conjunction with some palladium complexes of the mesityl(Mes)-substituted derivative,FcPMes(L1),and the non-bridged diphenylferrocenyl phosphine,Ph_(2)PFc(L3),are reported.Cyclic voltammetry studies on the bimetallic complexes[Ir(κ^(1)P-L2)(cod)Cl](1),[Ir(κ^(1)P-L2)(CO)2Cl](2),[AuCl(κ^(1)P-L2)](3),[Pd(κ^(1)P-L2)(η^(3)-allyl)Cl](4),[Pd(κ^(1)P-L3)(η^(3)-allyl)Cl](5),[Pd(κ^(1)P-L3)(2-aminobiphenyl)(SO_(3)CH_(3))](6),and[Pd(κ^(1)P-L1)(2-aminobiphenyl)(SO_(3)CH_(3))](7)provided indications for a good electronic communication between the metal atoms.In order to confirm that the[1]ferrocenophane or 1-ferrocenyl unit might be able to electrochemically influence the reactivity of the coordinated transition metal,the palladium complexes 4-7 were employed as redox-switchable catalysts(RSC)in Buchwald-Hartwig cross-coupling reactions.The catalytic activity depends on the ligand and decreases in the series L3>L2>L1.In stirred solutions,the reaction rate can be influenced by addition of an oxidizing reagent.Some reactions were accelerated with in situ generated,cationic complexes as catalysts as compared to their neutral analogs;in some cases,the activity was found to be lower.Furthermore,steric effects play a predominant role,among other factors.
