Magnetic Bistability in Mononuclear Iron(II) Pyrrolide Complexes and Cyano-bridged Chain Compounds

This presentation will describe our efforts to engender high magnetic relaxation barriers in low-dimensional coordination compounds. First, strong magnetic anisotropy in a family of iron(II) pyrrolide complexes is shown to give rise to the first examples of transition metal-based mononuclear single-molecule magnets. The anisotropy and relaxation dynamics of these complexes are examined through an array of magnetic and spectroscopic measurements. Next, a building block approach is employed to install strong coupling in cyano-bridged chain compounds. In particular, simple molecular orbital considerations are used to design and construct the compound (Bu ₄ N)[TpCuReCl ₄ (CN) ₂ ], which demonstrates the strongest ferromagnetic coupling ever observed through cyanide. Finally, this approach is extended toward the assembly of a series of single-chain magnets, (DMF) ₄ MReCl ₄ (CN) ₂ (M = Mn, Fe, Co, Ni). Most notably here, the field-dependent magnetization of the iron analogue exhibits significant hysteresis at low temperature, thus demonstrating classical magnet behavior in a one-dimensional solid.