Spin crossover in phosphorus- and arsenic-bridged cyclopentadienyl-manganese(II) dimers

Abstract

Manganocene reacts with LiE(SiMe3)2 (E = P or As) to give [(η5-Cp)Mn{μ-E(SiMe3)2}]2, where E = P (1) or As (2). The temperature dependence of the magnetic susceptibility in 1 and 2 is due to antiferromagnetic exchange and to spin-crossover (SCO). Compound 2 shows two-step SCO with hysteresis, involving high-spin (S = 5/2) and intermediate-spin S = (3/2) Mn(II).