Three new gallium complexes formulated as [Ga（PDA）2 ][Ga（H2O）（PDA）（phen）]·4H2O（1）,[Ga（PDA） 2]·（H2IN）·2H2O（2） and [Ga（OH）（PDA）（H2O）] 2（3）（H2PDA=pyridine-2,6-dicarboxylic acid;phen=1,10-phenanthroline;HIN=isonicotinic acid） have been synthesized under hydrothermal conditions.In the mixed-ligand system of complex 1,PDA2 and phen are connected to the central Ga 3＋ cation as tri-and bi-dentate ligands,respectively.In complex 2,each Ga 3＋ cation is six-coordinated by two PDA 2 anions octahedrally.Complex 3 shows a binuclear structure,with the bond distance of Ga1― Ga2 being 0.30061（3） nm.The 3D supramolecular structures of the three complexes are constructed via hydrogen bonds and aromatic π-π packing interactions.All the three complexes exhibit intense blue emission at room temperature in the solid state,which are attributed to π＊-π transition centered on the ligands.
A novel one dimension（1D） cadmium coordination polymer {[Cd（mpda）3]·2（NO3）}n（1） was synthesized via refluxing a mixture of tetradentate Schiff base ligand N,N＇-bis（2-pyridinylethylidene）phenylene-1,3-diamine（L） and Cd（NO3）2 in acetonitrile, whose structure was characterized by means of single crystal X-ray diffraction, FTIR spectroscopy, elemental analysis and proton nuclear magnetic resonance（1H NMR）. Center metal Cd（II） ion is six-coordinated by six nitrogen atoms from six different m-phenylenediamine（mpda）, giving rise to a [CdN6] octahe- dral coordination environment. The two adjacent cadmium centers are linked by three mpda molecules leading to the construction of 1D chain structure. The crystal structure is stabilized by N-H…O hydrogen bonds to form three-dimension supramolecule. Compound 1 exhibits intense yellow luminescence in solid state at 298 K（λem=554 nm）, which shows a blue shift at 77 K（ca. 147 nm）. Additionally, fluorescence characteristics of compound 1 were investigated in different solvents（polarity： DMSO〉CH3CN〉CH3OH〉CHC13〉toluene） at 298 and 77 K. The results show that the emission peak of compound 1 in solvent exhibits a slight bathochromic shift. However, the emission peaks of compound 1 in CH3OH and CHC13 are red shift compared with that in CH3CN. It is revealed that the lumi- nescence behavior of compound 1 depends on not only the polarity of solvent but also the hydrogen bonding proper- ties between solvent and solute. In addition, the emission peak of compound 1 in solution shows a red shift obviously at 77 K than that at 298 K（ca. 144-159 nm）, with the fluorescence lifetime increased at 77 K. The lifetime in DMSO at 77 K（r=12.470μs） was the longest one. The quantum yield of compoud 1 increases with increasing the polarity of solvent within a range of 1.8%-8.3 %.
XU Mengying LIU Zhigang FAN Ruiqing GAO Song CHEN Shuo YANG Yulin
