Pressure Effect on the 3-D Magnetic Ordering of a Quasi-1-D Enantiopure Molecular Magnet

Abstract

Magnetic measurements of the quasi 1-D molecular magnet formed by the coordination polymer of purely organic R-nitronyl nitroxide radical and manganese(II) ions, namely [(R)-3MLNN-Mn(hfac) 2 ], have been carried out under pressure up to 10 kbar at low temperatures. The results obtained show that the temperature of 3-D ferromagnetic ordering of the 1-D ferrimagnetic chains in this molecular magnet increases substantially under pressure. Analysis of the experimental data obtained, as well as a review of the ferromagnetic ordering temperature with respect to interchain coupling distances in closely related compounds, gives one grounds to suggest that the interchain magnetic coupling in the 3-D ferromagnetic ordering for this series of coordination complexes cannot be only dipolar (as often inferred). Rather, the interaction must be stronger, and in all likelihood, it is mediated mainly by exchange interactions.

Observation of the Pressure Dependent Reversible Enhancement of Tc and Loss of the Anomalous Constricted Hysteresis for [Ru2(O2CMe)4]3[Cr(CN)6]

“…This is in accord with the unusual metamagnetic-like hysteresis, [12] and is attributed and the weak ferromagnet 4-NCC 6 F 4 N 2 S 2 , and ferrimagnetic (R)-3MLNN-Mn(hfac) 2 (hfac = hexafluoroacetoacetonate) that increase at a rate of 0.22, [16] 1.13, [17] 1.81, [18] and 0.08 K kbar -1 , [19] respectively. In contrast, [TDAE][C 60 ] [TDAE = (Me 2 N) 2 C 2 (NMe 2 ) 2 ], and 4-nitrophenyl nitronylnitroxide decease with increasing pressure at a rate of -10 [20] and -0.034 K kbar -1 , [21] respectively.…”

Functionalized Nitronyl Nitroxide Biradicals for the Construction of 3d–4f Heterometallic Compounds

“…This approach has the following merits: (1) nitronyl nitroxides are remarkably stable and easy to chemically modify, thus allowing one to introduce various functional groups within the radical ligands; (2) nitronyl nitroxide radicals as spin carriers can directly coordinate to metal ions, thus leading to the strong possibility of magnetic coupling; , (3) functionalized nitronyl nitroxide radicals may link two or more metal ions, thus producing magnetic molecules with various spin topological structures and dimensionalities. Following this strategy, various magnetic systems have been obtained such as long-range magnetically ordered systems, chiral magnets, spin-transition-like species, single-chain magnets (SCMs), and single-molecule magnets (SMMs) . Recently, special attention of this approach has been placed on molecule nanomagnets (SCMs and SMMs) owing to their potential applications in high-density data storage, quantum computing, and molecular spintronics, and some appealing results have been achieved through this kind of route.…”

Subtle competition between ferromagnetic and antiferromagnetic order in a Mn(II)-free radical ferrimagnetic chain

“…However, the sign of this interaction cannot be simply deduced from structural consideration due to the complexity of the exchange paths. Note that previous magnetization measurements under pressure on Mn(hfac) 2 (R)-3MLNN also concluded the existence of ferromagnetic interchain exchange 44 . Polarized neutron experiments on a single-crystal could give more information on these interactions.…”