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Homoleptic Osmium Cyanide Complexes: Synthesis and Perspective Application in Molecular Magnetismстатья Глава в книге
- Автор: Vostrikova Kira E.
- Сборник: Osmium: Synthesis, Characterization and Applications
- Серия: Chemistry Research and Applications
- Глава в коллективной монографии
- Год издания: 2015
- Издательство: Nova Science Publishers
- Местоположение издательства: Hauppauge, NY, United States
- Первая страница: 43
- Последняя страница: 78
- DOI: https://www.novapublishers.com/catalog/product_info.php?products_id=55752
- Аннотация: In the past time the cyanometalate chemistry lived through an unpredicted revival, driven by a large amount of publications reporting the use of these complexes as building blocks in design of discrete and extended systems with potential applications as molecular magnets, photo-switchable materials and memory storage devices. Cyano-bridged assemblies have provided a large number of materials with single-molecule magnet (SMM) and single-chain magnet (SCM) behavior. Among them, several ones based on hexacyanoferrate(III) heterometallic SMM clusters and SCMs were prepared and magnetically studied. The octahedral [Fe(CN)6]3– anion represents an important orbitally-degenerate magnetic unit with unquenched orbital momentum; its incorporation in nanomagnets can potentially increase their magnetic anisotropy. However, anisotropy strength is sensitive to local polyhedron distortions in [FeIII(CN)6]3–. In this respect, its heavier counterpart, especially [OsIII(CN)6]3–, is more attractive anisotropic constituents due to a much stronger spin-orbit coupling energy and more diffuse magnetic orbitals resulting in larger magnetic spin coupling. There are only a few examples of the materials based on [OsIII(CN)6]3–, including the trigonal bipyramidal clusters [MII(tmphen)2]3 [OsIII(CN)6] (M = Fe, Ni, Mn), Prussian blue analogues MII3[OsIII(CN)6]2•nH2O (M = Co, Ni, Fe), three SMMs involving MnIII Schiff base complexes and the first osmium based SCM – (Ph4P)2[Mn(acacen)][Os(CN)6]. It has recently been shown that incorporation of [OsIII(CN)6]3– in MnIII–NC–MIII–CN–MnIII trinuclear complex considerably increases the SMM energy spin-reversal barrier compared to that of the MnIII–NC–FeIII–CN–MnIII cluster. This achievement opens new horizons for application of [OsIII(CN)6]3–in the design of magnetically bi-stable molecular systems. Therefore, development of facile, reliable and having high yield synthetic methods for the preparation of precursors and model compounds is highly demanded. The research of cyanide compounds has been a subject of several reviews over the years. Nevertheless, the scarce amount of information on homoleptic osmium cyanide complexes is astounding. Only cyanometallates(II) and (III) were structurally characterized to date despite the existence of higher oxidation states for osmium. Moreover, the homoleptic coordination compounds of Os comprise mainly hexaligated complexes, unlike its nearest neighbor, rhenium, which demonstrates coordination numbers from six to nine. In the chapter we review shortly the results on the osmium cyanides published pending 2006 and present the new data on the synthesis, properties and structure of cyanoosmates and their application in design of molecular nanomagnets. Recently we have developed a facile synthesis of the soluble in organic media paramagnetic (Cation)3[OsIII(CN)6] with different cations and pioneering preparation of (n-Bu4N)3[OsIV(CN)7]•0.5H2O, (Ph4P)2[OsIV(CN)6] and (n Bu4N)[OsV(CN)6] complexes.
- Добавил в систему: Vostrikova Kira E.