A linear metal–metal bonded tri-iron single-molecule magnet

Abstract

A trinuclear iron cluster possesses ferromagnetically coupled high-spin FeII centers and displays slow relaxation of the magnetization under applied field.

A New Look at Molecular and Electronic Structure of Homoleptic Diiron(II,II) Complexes with N,N‐Bidentate Ligands: Combined Experimental and Theoretical Study

“…The high-spin ground state and the suspected magnetic anisotropy prompted us to investigate 1 and 2 as promising candidates for single molecule magnets similar to a recently reported metalÀ metal bonded triiron molecule. [70] Therefore, we performed dynamic magnetic susceptibility measurements for both of them, but no out-of-phase signal was observed under the zero DC field, most probably due to the fast quantum tunnelling of magnetisation (QTM). This effect is efficiently quenched by applying a constant DC magnetic field, which led to the observation of the slow magnetic relaxation for 1 and 2, as presented in Figures S8-S11.…”

Metal–Metal-Bonded Fe4 Clusters with Slow Magnetic Relaxation

“…Like [Bu 4 N]­[( H L) 2 Fe 6 (py) 2 ], this cluster features a compact metal core with short Co–Co bonds (2.36 Å), which leads to slow magnetic relaxation. The Fe­(II) chain clusters [Fe 4 (tpda) 3 X 2 ] [H 2 tpda = N , N -bis­(pyridin-2-yl)­pyridine-2,6-diamine; X = Cl, Br] and [Fe 3 (DpyF) 4 ]­[BF 4 ] 2 (DpyF = dipyridylformamide) also exhibit ferromagnetic exchange and slow magnetic relaxation, − although in these examples, the Fe–Fe distances are relatively long (>2.8 Å). Several other Fe–Fe-bonded complexes also feature high-spin ground states as a consequence of direct exchange interactions, including [Na 6 Fe 3 (tris- cyclo -salophen)­(py) 9 ], [Fe­( i PrNPPh 2 ) 3 Fe­(PMe 3 )], [Fe 2 (DPhF) 3 ], and [Fe 2 (DPhF) 4 ] (DPhF = diphenylforamidinate). − Although the magnetic relaxation in these examples was not explicitly measured, the observation that direct M–M bonding can lead to ferromagnetic exchange further highlights the value of this design feature.…”

The structure of a pentachromium(II) extended metal atom chain at 3 K: Cotton’s conjecture proven

“…Arrays of closely spaced metal ions lined up into wire-like structures are known as extended metal atom chains (EMACs) 1 and have been the focus of intense investigation over the past two decades. [2][3][4][5][6][7] This linear topology is often assembled using specifically designed organic ligands, like fully deprotonated oligo--pyridylamines in the all-syn conformation, and may lead to the formation of metal-metal bonds. 8,9 The structural resemblance of EMACs to macroscopic wires and the possibility of a strong electronic communication among metal centers have suggested the perspective use of these species as nanoscale wires in molecular electronics.…”

“…A particularly lively debate arose around the X-ray structure of pentachromium(II) EMACs [Cr5(tpda)4X2], which contain four dianions of N 2 ,N 6 -di(pyridin-2-yl)pyridine-2,6-diamine (H2tpda) and X = Cl − (1) or SCN −…”