Molecular magnets materials

Stability of diradicals is important for photochemical reactions. Spin multiplicity of the ground states is critical for the molecular magnetic materials. The relative stability of singlet (triplet) isomers and the spin multiplicity of the ground states (spin preference) [48] has been described to introduce the orbital phase theory in Sects. 2.1.5 and 2.1.6. Applications for the design of diradicals are reviewed by Ma and Inagaki elsewhere in this volume. Here, we briefly summarize the applications. 

Miller, J.S. and Epstein, A.J.( 1994) Organic and organometallic molecular magnetic-materials -Designer magnets, Angew. Chem., 33, 385 115. 

Cyanide complexes have a venerable history (see CCC S )),1 and find utilization in many industrial processes including as synthetic catalysts e.g., Co cyanides on inorganic supports catalyze alkylene oxide polymerization,187 molecular magnetic materials, in electroplating, and in mining. Their pharmacology and toxicology is well explored... 

Highly stable 4-(benzimidazol-2-yl)-2,6-di-t-butylphenoxyl radicals have been synthesized. Their hydrogen-bonding functionality offers prospects for use in molecular magnetic materials. ... 

Figure 1. Macromolecular architectures with open-shell repeating units used to build organic/molecular magnetic materials.

Figure 5.39. Molecular structures of other molecular magnetic materials. Illustrated are (a) tris(oxalato) metalates [M M (ox)3], where M I=Mn, Fe, Ni, Co, Cu, Zn M =Cr, Fe, Ru, and (b) the simplified crystal structure of Prussian Blue, with an example of the analogue structure [(tacn)8Co8(CN)i2], where the tacn ligand is 1,4,7-triazacyclononane. Reproduced with permission from (a) Min, K. S. Rhine-gold, A. L. Miller, J. S. Inorg. Chem., 2005, 44, 8433, and (b) Belttan, L. M. C. Long, J. R. Acc. Chem. Res., 2005, 38, 325. Copyright 2005 American Chemical Society.

Bis(P-diketones) ligands, were proved to be efficient motifs or structural elements for selfassembling highly luminescent metallo-supramolecular lanthanide complexes [53-59] and representative examples (H2L" ) are shown in Figure 2.8. Special attention has also been paid to the use of enantiomerically pure bis-P-diketones ofH2L " [58]. H2L ° in Figure 2.8 was shown to have the ability to form d-f-d molecular magnetic materials [60]. 

Einally, an interesting area of magnetoelastic instability resulting in field-induced cooperative phenomena in molecule-based magnets has recently been opened [189, 190]. This area is expected to be promising in the control of the properties of molecular magnetic materials by means of external fields. 

Magnetic interactions of a paramagnetic metal center and a free radical ligand are of interest for the development of new types of molecular magnetic materials. Complexes of this type (such as (83)) change their magnetic properties upon irradiation by visible light and can serve as a basis for development of novel photo-activated memory units for electronic devices.346,347... 

The experimental observation of resonant tunneling [12,13] of magnetization in the Mni2-Acetate molecule [14] has focused significant attention on molecular magnets and molecular magnetic materials [15-39]. This molecule represents the anisotropic class of molecules. 

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