High- T _c Molecular-Based Magnets: Ferrimagnetic Mixed-Valence Chromium(III)-Chromium(II) Cyanides with T _c at 240 and 190 Kelvin

Abstract

Molecular-based magnets with high magnetic-ordering temperatures, T(c), can be obtained by mild chemistry methods by focusing on the bimetallic and mixed-valence transition metal micro-cyanide of the Prussian blue family. A simple orbital model was used to predict the electronic structure of the metal ions required to achieve a high ordering temperature. The synthesis and magnetic properties of two compounds, [Cr(5)(CN)(12)].10H(2)O and Cs(0.75) [Cr(2.125)(CN)(6)].5H(2)O, which exhibited magnetic-ordering temperatures of 240 and 190 kelvin, respectively, are reported, together with the strategy for further work.

Magnetic Properties and Metastable States in Spin-Crossover Transition of Co–Fe Prussian Blue Analogues

“…Some of the Prussian blue analogues (PBAs) [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] show thermal-induced phase transitions and photomagnetic effects. [39][40][41][42][43][44][45] In such materials, a strong cooperativity operates since transition-metal ions are bridged by CN ligands with a three-dimensional network structure.…”

Long‐Range Magnetic Ordering in a TbIII–MoV Cyanido‐Bridged Quasi‐One‐Dimensional Complex

“…[1][2][3] In this regard, cyanido-bridged heterobimetallic assemblies derived from [M(CN) 6 ] 3À (M = Cr, Fe, Co) building blocks and various transition metal or rare earth metal ions have been extensively explored. [4][5][6][7][8] More recently, [M(CN) 8 ] 3À/4À (M = Mo, W) anions have become attractive building blocks for the synthesis of new cyanido-bridged networks with remarkable magnetic and photomagnetic properties. [9][10][11] Octacyanidometallates profit from the enhanced p backbonding and superexchange efficiency resulting from the greater diffuseness and radial distribution of 4d/5d orbitals as compared with 3d orbitals.…”

Organic Ferromagnets

“…According to the nature of M and M', ferro-, ferri-and antiferro-magnets can be obtained. The highest critical temperatures reported so far [2], 240 K for the ferrimagnet [Cr5(CN)12]10H20, are already close to room temperature, but in this case the role of organic chemistry is rather meager (is a cyanide organic or inorganic? ).…”