Access to Heteroleptic Fluorido‐Cyanido Complexes with a Large Magnetic Anisotropy by Fluoride Abstraction

Abstract

Silicon‐mediated fluoride abstraction is demonstrated as a means of generating the first fluorido‐cyanido transition metal complexes. This new synthetic approach is exemplified by the synthesis and characterization of the heteroleptic complexes, trans‐[MIVF4(CN)2]2− (M=Re, Os), obtained from their homoleptic [MIVF6]2− parents. As shown by combined high‐field electron paramagnetic resonance spectroscopy and magnetization measurements, the partial substitution of fluoride by cyanide ligands leads to a marked increase in the magnetic anisotropy of trans‐[ReF4(CN)2]2− as compared to [ReF6]2−, reflecting the severe departure from an ideal octahedral (Oh point group) ligand field. This methodology paves the way toward the realization of new heteroleptic transition metal complexes that may be used as highly anisotropic building‐blocks for the design of high‐performance molecule‐based magnetic materials.

Chemical Control of Spin‐Orbit Coupling and Charge Transfer in Vacancy‐Ordered Ruthenium(IV) Halide Perovskites

“…Separately, there has been significant interest in the single‐ion physics of vacancy‐ordered double perovskites and related systems of heavy transition metals. Some progress has been made in this direction on Re IV (5 d 3 ), [19, 20] Os IV (5 d 4 ), [21, 22] and Ir IV (5 d 5 ), [23] halides, with the last two exhibiting strong spin‐orbit coupling (SOC) effects. The ability to tune the strength of SOC can give rise to a plethora of ground states of interest to quantum sensing and computing [24] …”

Magnetostructural and EPR Studies of Anisotropic Vanadium trans-Dicyanide Molecules

“…While magnetic measurements can, in theory, provide estimates of ZFS parameters, inaccuracies often arise due to insufficient constraints provided by bulk thermodynamic data . It is better to use a spectroscopic technique such as EPR (in this case, high-field EPR due to the sizable ZFS energies involved), , which directly measures energy splittings that can be related to ZFS parameters in a straightforward manner.…”

Pentagonal-bipyramidal 4d and 5d complexes with unquenched orbital angular momentum as a unique platform for advanced single-molecule magnets: current state and perspectives

“…The best-known examples are pentagonal-bipyramidal d 2 complexes [Mo IV Cl 2 (DAPBH)] (H 2 DAPBH = 1,1′-(pyridine-2,6-diyl)bis(ethan-1-yl-1-ylidene))dibenzohydrazine 76 and W IV (CN) 7 2− 77 with S = 1, as well as a number of octahedral d 3 complexes ( S = 3/2), such as [Mo III (CN) 6 ] 3− , 78 [Mo III Cl 6 ] 3− , 79 [Re IV F 6 ] 2− , 80 [Re IV Cl 4 (CN) 2 ] 2− , 81 [Re IV F 4 (CN) 2 ] 2− . 82 These complexes exhibit a non-degenerate (spin-only) ground orbital state characterized by large ZFS energies with the axial parameter D reaching a value of 330 cm −1 , as is the case in W IV (CN) 7 2− . 77 Enhanced ZFS energies are caused by the considerably stronger SOC in heavy transition metal ions, especially in 5d ions.…”

“…75 High-spin ground state (S > 1/2) can only occur in some highly symmetric d 2 . 82 These complexes exhibit a non-degenerate (spin-only) ground orbital state characterized by large ZFS energies with the axial parameter D reaching a value of 330 cm −1 , as is the case in W IV (CN) 7 2− . 77 Enhanced ZFS energies are caused by the considerably stronger SOC in heavy transition metal ions, especially in 5d ions.…”