Synthesis And Magnetism Of Cyano-Bridged Low-Dimensional Molecular Nanomagnets

With the rapid development of information industry,the requirements for information storage materials are also increasing.It is a huge challenge to realise high-density information storage due to that the traditional magnetic materials face the size limitation problem.Therefore,molecule-based magnetic materials(single-molecule magnets and single-chain magnets)which using a single molecule as a storage unit have become one of the hottest topics in related fields in recent years.In this paper,three building blocks with different numbers of cyano groups,[Fe(Pz Tp)(CN)3],[WV(CN)8]3-and [MoV(CN)8]3-,were utilizied to assemble withand transition metals in the presence of different auxiliary ligands.Their single-molecule and single-chain magnet properties were studied and discussed.The results are as follows:(1)Using the tricyanometalate [Bu4N][Fe(Pz Tp)(CN)3] building block with transition metal NiIIions and auxiliary ligands 4,4?-dimethoxy-2,2?-bipyridine(4,4?-dmobpy),we obtained two Fe~?2Ni~?2 compounds,namely 1 and 2.Both 1 and 2 exhibit intramolecular ferromagnetic coupling interactions and field-induced slow magnetic relaxation.The energy barrier are 12.8 K and 13.0 K,respectively.their single-molecule magnet properties as well as the magneto-structral correlations were discussed.Using [Bu4N][Fe(Pz Tp)(CN)3] building block with transition metal Ni~?and Mn~?ions and auxiliary ligands4,4?-bis((1H-imidazol-1-yl)methyl)-1,1'biphenyl(4,4?-bimbp),we obtained two one-dimensional chain compounds 3 and 4.Compound 3 exihbits intrachain ferromagnetic coupling but no slow magnetic relaxation.Structrual analysis shows that compound 4 has a more distorted bond angle of C?N–Mn,which may lead to a reduction in the overall magnetziation.Magnetic characterization reveals that it only shows ferrimagnetic interaction.(2)Three network-like compounds 5-7 were synthesized by using octacyano building blocks [WV(CN)8]3-and [MoV(CN)8]3-to react with transition metal ions(Mn~?and Fe~?)and auxiliary ligands of 2,5-di(1H-imidazol-1-yl)thiophene(dimtp)and1,4-bis(pyridine-4-ylmethyl)piperazine(bpmp).Magneto-structrual correlation reveals that 5exhibits ferromagnetic interaction while compounds 6 and 7 are both antiferromagnetic one.None of them exhibit the nanomagnet properties or long range ordering.