New chromium, molybdenum, and cobalt complexes of the chelating esp ligand

TitleNew chromium, molybdenum, and cobalt complexes of the chelating esp ligand
Publication TypeJournal Article
Year of Publication2019
AuthorsPakula RJ, Martinez AM, Noten EA, Harris CF, Berry JF
JournalPolyhedron
Volume161
Start Page93
Pagination93-103
Date Published03/2019
ISSN0277-5387
Accession Number2019:122662
Abstract

Bimetallic carboxylates of Rh(II) are widely recognized for their ability to catalyze carbene transfer reactions such as the cyclopropanation of olefins using org. diazo compds. as carbene precursors.  A major goal in catalysis is to find cheaper, more Earth-​abundant alternatives to precious metal catalysts.  There is therefore currently great interest in the bimetallic paddlewheel chem. of elements that have lower costs and greater terrestrial abundance than Rh.  M2(esp)​2(L)​2 structures were synthesized and structurally characterized with M = Cr, Co, and Mo, where esp2-​ = α,​α,​α',​α'-​tetramethyl-​1,​3-​benzenedipropionate, a chelating dicarboxylate ligand that helps stabilize the bimetallic core.  Cr2(esp)​2(THF)​2, Mo2(esp)​2, and Co2(esp)​2(EtOH)​2 were tested as catalysts for decompn. of the diazo compd. (4-​bromophenyl)​diazoacetate Me ester in the presence of styrene; while the Cr2 and Mo2 complexes showed no difference from a background control, the Co2 complex was found to enhance the rate of dinitrogen extrusion and promote carbene addn. to styrene to form the cyclopropane product.

URLhttps://doi.org/10.1016/j.poly.2018.12.045
DOI10.1016/j.poly.2018.12.045