Advanced Photonics Center School of Electronic Science and Engineering Southeast University Nanjing 210096 China;
Department of Chemistry Taishan University Shandong 271021 China;
School of Chemistry and Chemical Engineering Zhongshan University Guangzhou 510275 China;
coordination polymer; palladium(Ⅱ) complex; 2; 6-pyridinedicarboxylic acid; crystal structure;