Iron(II) complexes bearing anilido-imine ligands: Synthesis and catalysis on ATRP of methyl methacrylate

Abstract

Reactions of the ortho-C6H4(NHAr)-(CHNAr) with nBuLi and subsequent addition of FeCl2 afford the anilido-aldimine Fe(II) complexes [(ArNCHC6H4-NAr)Fe]2(μ-Cl)2 (Ar=2,6-Me2C6H3 (1a); Ar=2,6-Et2C6H3 (1b)), and (ArNCHC6H4-NAr)Fe(μ-Cl)2Li(THF)2 (Ar=2,6-iPr2C6H3 (1c)). Similarly, reactions of the 2-(ArNC(H))C6H4-HNC9H6N with nBuLi and FeCl2 give the N,N,N-tridentate iron complexes {[2-(ArNC(H))C6H4-NC9H6N]Fe}2(μ-Cl)2 (Ar=2,6-Me2C6H3 (2a), 2,6-Et2C6H3 (2b), and 2,6-iPr2C6H3 (2c)). The X-ray diffraction analysis reveals that 1a and 1b are dimeric complexes and 1c is hetero-binuclear complex. Fe(II) atoms in these complexes are all in a distorted tetrahedral geometry. Complex 2c was confirmed to be a dimeric complex with the iron atom in a trigonal bipyramidal geometry. Complexes 1a–1c show moderate activities in ATRP of MMA in the presence of benzyl chloride (BnCl). While complexes 2a–2c are inert under the same condition.