Ligand redistribution reactions for the synthesis of heterobimetallic rare-earth metal complexes of Co(ii) and Fe(ii)

Abstract

Reactions of the yttrium complex [AdNPPh₂]₃Y (1) with CoCl₂ and FeCl₂ led to the isolation of a heterobimetallic Y(III)–Co(II) complex and a diiron complex [AdNPPh₂]₃Fe₂Cl (4), respectively. In the presence of KC₈/18-c-6 as a reductant, the reaction of 1 with CoCl₂ afforded a dicobalt complex [AdNPPh₂]₃Co₂ClK(18-c-6) (3). These reactions proceeded via ligand redistributions caused by halide abstraction from the Lewis acidic and electropositive Y(III) center. Treatment of the β-diketiminato yttrium complex L^nacnacY[PhNCH₂PPh₂]₂ (5) with FeCl₂ led to the formation of the complex [PhNCH₂PPh₂]₂[PhN(Ph)NCH₂PPh₂]Fe₂Cl (6), via ligand redistribution and P–C bond cleavage. All complexes are paramagnetic and are characterized by X-ray diffraction studies.