Reductive Coupling of CO Templated by Iron Bound to the Tris(pyrrolide)ethane Scaffold
Year: 2011
Type: article
Abstract: The reactivity of the high-spin ( S = 2) [( Mes tpe)Fe(THF)][Li(THF) 4 ] ( 1 ) complex ( Mes tpe = tris(mesitylpyrrolide)ethane) with isocyanide and CO substrates is explored. Reaction of 1 with excess t BuNC forms a low-spin ( S = 0), six-coordinate iron(II) species with three t BuNC ligands bound to iron, producing a notable tautomerization of one of the pyrrolide units from N- to C-ligation to iron. Reaction of 1 with an atmosphere of CO also produces a new diamagnetic complex, wherein two molecules of CO are consecutively reductively coupled, driven by the two-electron oxidation and fragmentation of the tris(pyrrolide)ethane ligand. The product features a six-coordinate Fe(II) species bound to a dipyrromethene ligand (resulting from oxidative fragmentation of the Mes tpe ligand), an oxalyl-imino pyrrole fragment from pyrrole coupling to two molecules of CO. The reactions of 1 with t BuNC and CO provide insight into how tautomerization of the tris(pyrrolide) ligand upon substrate binding initiates the contiguous reductive coupling of CO.
Source: Organometallics
DOI: 10.1021/om2003859
Authors: Graham T. Sazama, Theodore A. Betley
Institution: Harvard University
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2320335830