Vanadium(II) Heptacyanomolybdate(III)-Based Magnet Exhibiting a High Curie Temperature of 110 K

Abstract

We prepared a vanadium heptacyanomolybdate-based magnet, V(II)(2)[Mo(III)(CN)(7)].(pyrimidine)(2).4.5H(2)O (VMo), with a Curie temperature (T(C)) of 110 K, which is the highest T(C) value in [Mo(III)(CN)(7)]-based magnets. Additionally, Mn(II)(2)[Mo(III)(CN)(7)].(pyrimidine)(2).2H(2)O (MnMo) of a monoclinic structure (P2(1)/n) with T(C) = 47 K was prepared to confirm the crystal structure of VMo.

Enhanced Single‐Chain Magnet Behavior via Anisotropic Exchange in a Cyano‐Bridged MoIII–MnII Chain

“…In this vein, the [Mo III (CN) 7 ] 4− unit is a very attractive starting material as evidenced by the fact that strong exchange between Mo III spins with other metal ions through bridging cyanide groups leads to high T c magnets with the highest T c value being 110 K for a V II –Mo III compound . In the context of the present study, the strong anisotropic Mo III –CN–Mn II exchange interaction, which was first theoretically proposed, was experimentally confirmed to be promising for the preparation of high T B SMMs by Dunbar and Wang .…”

Molecular Engineering of High Energy Barrier in Single-Molecule Magnets Based on [MoIII(CN)7]4− and V(II) Complexes

“…Especially intense exchange interactions are expected between [Mo III (CN) 7 ] 4− complexes and vanadium(II) ions, which, similarly to Mo III ions, also tend to form strong exchange interactions due to more diffuse 3d orbitals of early transition metal ions [67]. However, data on the exchange parameters in [Mo III (CN) 7 ] 4− -V II based molecular magnets are scarce or absent [68]. The magnitude of exchange interactions in cyano-bridged pairs Mo III -CN-M(3d) can be estimated from available experimental data for the related hexacyano complex [Mo III (CN) 6 ] 3− , J = −122 cm −1 [57] and J = −228 cm −1 [58] for Mo III -CN-V II cyano-bridged pairs; very large exchange parameters for the Mo III -CN-V II linkages in a Prussian blue type structure were also predicted from a broken symmetry DFT study (J ≈ 350 cm −1 ) [59].…”

Microporous magnets

“…For this reason, hepta-and octacyanometallates have been investigated recently for the formation of molecule-based magnets with high ordering temperatures. 119,120 However, only a few of these have this far been demonstrated to be porous. 73,80 Finally, it is interesting to note that most of permanent magnets with high ordering temperatures are based on magnetism arising from itinerant electrons, [121][122][123] instead of classical superexchange.…”