Synthesis and Magnetic Properties of Linear Two-coordinate Monomeric Diaryliron(II) Complexes Bearing Fused-ring Bulky “Rind” Groups

Monomeric diaryliron(II) complexes, Fe(Rind)2, have been obtained by introducing fused-ring bulky “Rind” groups. For Fe(Eind)2, a significant orbital contribution of the Fe(II) ion due to the linear two-coordination has been determined by the highly effective magnetic moment (μeff = 5.82 μB) and the extraordinarily large internal hyperfine field (Hn = ca. 140 T) in the Mössbauer spectrum. Variable-frequency out-of-phase ac susceptibility data demonstrate an effective spin-reversal barrier of Ueff = 51.2(7) cm−1 associated with the single-ion magnet behavior.