Synthesis,Structure And Optical,Electrical And Magnetic Properties Of Metal N-heterocyclic Complexes

The design and construction of porous coordination complexes（PCCs）built by metal ions/clusters and organic ligands have attracted considerable interest.Especially,multifunctional PCCs can realize more efficient,flexible and smart applications because different functions,such as sensing,optical,electrical and magnetic properties,can exist separately or act in synergy,resulting in more efficient,flexible and smart applications.N-heterocyclic ligands are an important class of N-donor ligands and have been well established for achieving PCCs,which are ideal for constructing complexes with noval structure because of strong coordination ability and diversified coordination modes.In this paper,metal coordination complexes with optical,electrical and magnetic functions are constructed by using N-heterocyclic ligands.The main research contents are as follows:（1）An ultra-stable Cu（I）-tetrazolate complex,Na Cu₃（mtz）₄（1,mtz=5-methyltetrazolate）,was prepared in suit using Cu（Cl O₄）₂·6H₂O,Na N₃and acetonitrile by solvothermal approach.X-ray crystallographic analysis revealed that complex 1 contains a 3D anionic[Cu₃（mtz）₄]^-framework with 1D channels and counter Na⁺cations along the b direction.It exhibits high thermal outstanding chemical stabilities under various conditions,including water,organic solvents,and acidic and basic solutions of wide p H range（3～11）.The coordination behavior of Cu-N bonds based on the hard and soft acid-base principle,which is responsible for the ultra-stability of 1.The complex 1 exhibits strong green emissions,which can be ascribed to metal-to-ligand charge transfer and complex 1 is highly desirable as a fluorescent nitrobenzene sensor with high selectivity and sensitivity under water.Moreover,complex 1 presents a high proton conductivity of over 10^-2S cm^-1at 70°C and 100%relative humidity,which is comparable to the commercial Nafion polymers.In 1,abundant uncoordinated nitrogen atoms on the pore walls act as H-bonding acceptors to achieve its high proton conductivity under water-assisted conditions.Complex 1 is an unprecedented water-dependent proton conductor of the tetrazole-based complex.Complex 1 is a rare porous tetrazole-based complex with both proton-conducting and luminescence sensing properties.（2）A multifunctional complex,[Dy₂（IA）₄（phen）₄]（Cl O₄）₂（H₂O）₄（2,HIA=imidazole-4-acetic acid hydrochloride,phen=1,10-phenanthroline）,was prepared using Dy（Cl O₄）₃,imidazole-4-acetic acid hydrochloride and 1,10-phenanthroline by solvothermal approach.X-ray crystallographic analysis revealed that complex 2 features a dinuclear structure bridged by carboxylate oxygen atoms of the HIA ligands,and its supramolecular network contains a 1D stacking channel.The ac susceptibility of complex 2 show frequency dependencies,which is a typical slow magnetic relaxation property of SMMs,U_eff/K=15.4 K andτ₀=7.6×10^-7s were obtained.The solid-state luminescence spectrum of complex 2 displays strong emission and long luminescence lifetime.In addition,complex 2 shows a moderate proton conductivity with 1.05×10^-6S cm^-1（45°C and 100%RH）,which may be ascribed to the 1D-extended H-bonds in the 1D stacking channel of complex 2.The complex is a rare multifunctional complex with single-molecule magnet,proton conduction,and luminescence properties.