Synthesis,Characterization And Dielectric Properties Of A Series Of Organic-inorganic Hybrid Cyano-bimetallates

Dielectric transition materials are a type of molecule-based responsive materials with switchable dielectric constant between low-and high-dielectric states.They would find applications in fields such as switching and sensing.This dissertation focuses on the dielectric transition behaviors of a series of organic-inorganic hybrid cyano-bimetallates.It contains four parts:Part Ⅰ:A series of organic-inorganic hybrid cyano-metallates are obtained by combining protonated amine guests with K3[Co(CN)6].It is found that the guests modulate the structures of the cyano-bimetallates.Several dielectric transition compounds are screened.Part Ⅱ:Three compounds,i.e.,(MA)2[B1Co(CN)6](MA = methylarnmmonium cation;B’ = Na,1;K,2;Rb,3),are obtained by combining MA guest with B’3[Co(CN)6].Compounds 1-3 show dielectric transition behaviours.Notably,the square root of dielectric transition temperature(Ttr)and the radius of the B’ ion had a linear relationship.Part Ⅲ:B’-site mixed compounds(MA)2[K1-xRbxCo(CN)6](x = 0.38,4;0.56,5;0.66,6;0.69,7;0.77,8)are obtained based on 2 and 3.The Ttr of the series of compounds can be finely tuned by the B’-site mixing.Part Ⅳ:Compound(HPy)2[Na(H2O)2Co(CN)6](HPy = pyridinium cation,9),together with its semi-dehydrated form(HPy)2[Na(H2O)Co(CN)6](10),is obtained by combining pyridinium chloride with Na3[Co(CN)6].Compound 9 and 10 can transform to each other via a dehydration-rehydration process.In particular,10 undergoes a thermal-driven dielectric transition,corresponding to a new type of dielectric transition materials.