Structures And Properties Of The Composites Based On Heteropoly Acids And Phenanthroline/biquinoline Metal Coordination Compounds

The heteropoly acid of type Keggin structure is an excellent solid proton conductor with unique ionic structure,it plays an important role in the development of functional materials.Based on the novel structure and excellent properties,the composites of Keggin type heteropoly acids and phenanthroline/biquinoline metal complexes have great potential applications in light,electricity and other fields.In this paper,three proton-conductive complexes based–on decorated Keggin-type clusters,{[Cu?dmphen??DMF?₂?H₂O?]₂[Si W₁₂O₄₀]}·6H₂O?1??{[Zn?dmphen??DMF?₂?H₂O?]₂[Si W₁₂O₄₀]}·6H₂O?2?and{[Cu?dmphen??CH₃CN?₂?CH₃OH?]₂[Si W₁₂O₄₀]}·4H₂O?3??wheredmphenis4,7-dimethyl-1,10-phenanthroline and DMF is N,N-dimethylformamide?,were simply synthesized by the reaction of H₄Si W₁₂O₄₀?24H₂O,Cu Cl₂?2H₂O/Zn Cl₂ and dmphen at room temperature.The products were structurally characterized by elemental analyses,infrared spectroscopy,and single-crystal X-ray diffraction analyses,Single-crystal X-ray diffraction analyses at 293 K revealed that three complexes crystallized in the monoclinic space group C2/c?1 and 2?and P2₁/_C?3?.The results of thermogravimetric analyses suggest that three complexes have good water holdingin one-dimensional hydrophilic channels in the temperature range 20¹00°C.Three complexes exhibit good proton conductivities(over 10^-5 S cm^-1 for 1?3 and over10^-4 S cm^-1 for 2)at 100°C in the relative humidity range 35⁹8%.Then,through the self-assembly of diethyl 2,2'-biquinoline-4,4'-dicarboxylic acid?L?,Cu²⁺with Keggin structure heteropoly acid,we successfully synthesized two complexes,namely:[Cu?L?₂]₂[HPW₁₂O₄₀]·4H₂O?complex 4?and[Cu?L?₂]₂[HPW₁₂O₄₀]·L·4H₂O?complex 5?.The products were structurally characterized by elemental analyses,infrared spectroscopy,and single-crystal X-ray diffraction analyses:?1?Single-crystal X-ray diffraction ananlyses at 293K revealed that these two compounds crystallized in the triclinicspace group P-1;?2?The results of thermogravimetric analyses suggest that two complexes have good water holding in the temperature range 20¹00°C.;?3?The infrared spectra show that the characteristic peaks of organic ligands?L?and heteropoly acid anions;?4?Two complexes exhibit good proton conductivities(over 10^-5 S cm^-1 for 4 and over 10^-4 S cm^-1 for 5)at 100°C in the relative humidity range 35⁹8%.;?5?X-ray powder diffraction analysis showed that the crystal structure of the compounds was not changed before and after the AC impedance test;?6?Upon excitation at 340 nm,two complexes display two main emission peaks centered at 470 nm and 526 nm,respectively.