Gold-based catalysts are topical heterogeneous and molecular species,the chemical diversity of which can be expanded through heterometal doping.Herein,we leverage a carbonyl-free metal-metal salt metathesis protocol t...Gold-based catalysts are topical heterogeneous and molecular species,the chemical diversity of which can be expanded through heterometal doping.Herein,we leverage a carbonyl-free metal-metal salt metathesis protocol to access rare examples of low-valent tantalum/gold multimetallics.The initial reaction between[Ta(naphthalene)_(3)]^(-)and gold(I)synthons affords a trimetallic monohydride cluster(2).Whereas dihydrogen addition to 2 results in deauration en route to a Ta-μH_(2)-Au complex(1),oxidative transformations—either addition of chemical oxidants or cluster protonation—conserve the trimetallic core,even in the absence of a polynucleating ligand.The resultant series of compounds provides experimental anchors for computational interrogation of polarized metal-metal interactions as a function of metal identity,formal oxidation state,and ligand sphere.The electronic structure of these clusters showcases significant Ta-arene covalency,even at higher oxidation states,rationalizing a recalcitrance to undergo ligand substitution.Furthermore,the addition of in situ generated Au^(+)to 2 results in an arene C-H activation process,highlighting that the naphthalene ligands in these complexes are simultaneously substitutionally inert and prone to functionalization.展开更多
基金supported by the University of Michigan and the NSF(Graduate Research Fellowship to M.L.M.—DGE-2241144,XRD Instrumentation—CHE-0840456).
文摘Gold-based catalysts are topical heterogeneous and molecular species,the chemical diversity of which can be expanded through heterometal doping.Herein,we leverage a carbonyl-free metal-metal salt metathesis protocol to access rare examples of low-valent tantalum/gold multimetallics.The initial reaction between[Ta(naphthalene)_(3)]^(-)and gold(I)synthons affords a trimetallic monohydride cluster(2).Whereas dihydrogen addition to 2 results in deauration en route to a Ta-μH_(2)-Au complex(1),oxidative transformations—either addition of chemical oxidants or cluster protonation—conserve the trimetallic core,even in the absence of a polynucleating ligand.The resultant series of compounds provides experimental anchors for computational interrogation of polarized metal-metal interactions as a function of metal identity,formal oxidation state,and ligand sphere.The electronic structure of these clusters showcases significant Ta-arene covalency,even at higher oxidation states,rationalizing a recalcitrance to undergo ligand substitution.Furthermore,the addition of in situ generated Au^(+)to 2 results in an arene C-H activation process,highlighting that the naphthalene ligands in these complexes are simultaneously substitutionally inert and prone to functionalization.
