Synthesis And Characterization Of Tricyano-and Octacyano-Bridged Low-Dimensional Molecular Magnets

Cyanide-bridged molecule-based magnets have been considered as the promising candidates for high-density information storage and spintronic devices,also it opens the door to new functionalities like quantum computation and molecular light switches.Thus,how to achieve controllable preparation of molecule-based magnets utilizing molecular engineering has become one of the most hotspots in the field of material chemistry at present.In this paper,the steric hindrance effect of cyanide building blocks and organic auxiliary ligands are discussed respectively to study the magneto-structural correlations of molecule-based magnets,and realize the construction of single-molecule magnets and low-dimensional light-induced molecular magnets.The main research achievements are as follows:（1）Three tricyanide-bridged complexes 1-3 were synthesized by the self-assembly of the tricyanide building blocks with different steric hindrance([Bu₄N][Fe(Tp^Me)（CN）₃],[Bu₄N][Fe（pzTp）（CN）₃]and[Bu₄N][Fe（Tp^*）（CN）₃]),the Ni^III ion featuring large spin-orbit coupling,and bidentate auxiliary ligands（4,4′-diethoxy-2,2′-bipyridine and 4-chloro-2,2′-bipyridine）.The three complexes all exhibit ferromagnetic behavior.Besides,complex 1 show field-induced magnetic relaxation and complex 3 show single-molecule magnets.（2）Five octacyanide-bridged complexes 4-8 were synthesized by the reaction of the octacyanide building blocks(K₄[Mo^IV（CN）₈]·2H₂O and K₄[W^IV（CN）₈]·2H₂O),multidentate auxiliary ligands（2,6-bis（3,5-dimethylpyrazol-1-yl）pyridine,tris（2-pyridylmethyl）amine and N-benzyl-N,N’,N’’-tris（2-pyridylmethyl）ethylenediamine）,and transition metal ions(Fe^II,Co^II,Cu^II and Mn^II).They all exhibit antiferromagnetic behavior.Among them,complex 4-5 have1D chain-like structures,and complex 6 has a 3D network-like structure.While complex 7-8have 0D cluster-like structures,and show photomagnetic properties.Under the laser irritation of 405nm,the spin transition behavior of Mo^IV centers in complex 7-8 can be induced by light.