Syntheses,Structure And Properties Of Ln-TM(3d-4f) Heterometallic Coordination Polymers

In recent years,heterometallic coordination polymers simultaneously consisting of both lanthanide?Ln?and transition-metal?TM?cations have seized considerable attention since the incorporation of two kinds of metal ions into a framework can add different functionalities and potential applicatios.In fact,it remains still a great challenge in the synthesis of Ln-TM heterometallic coordination polymers because of the fact that competition reactions of Ln and TM cations coordinated to the same ligand often leads to the formation of the homometallic coordination polymers.An effective strategy is to utilize the bridging ligands with different functional groups and donor atoms,like O and N atoms to react with Ln and TM cations to construct novel Ln-TM heterometallic coordination polymers.In this article,we choose 2,3-quinolinedicarboxylic acid?H₂QDA?and 2,3-pyridinedicarboxylic acid?H₂pydc?as multidentate ligands,Ni???,Co???,Cu???and Ln???cation as the metal centers,and successfully obtained nine Ln-TM heterometallic coordination complexes with novel structure under hydrothermal conditions.All of them were characterized by elemental analysis,infrared spectroscopy?IR?,and powder X-ray diffraction and further determined by single-crystal X-ray diffraction analysis.The thermal stabilities and luminescent properties of selected complexes were investigated.Main work is summarized as follows:1.One lanthanide-transition metal heterometallic complex was obtained,[Ln₄Ni?QDA?₂?QA?₆?OH?₄?H₂O?₄]?Ln = Dy 1,H₂ QDA =2,3-Quinolinedicarboxylic Acid,HQA = 3-Quinolinecarboxylic Acid?.It is interestingly that in situ decarboxylation of part H₂ QDA occurs and H₂ QDA is transformed into 3-quinolinecarboxylic acid.The thermal stability of the complex was investigated.2.Seven lanthanide-transition metal heterometallic complexes were synthesized by using 2,3-quinolinedicarboxylic acid as ligand,[Ln₄Co?QDA?₂?QA?₆?OH?₄?H₂O?₄]?Ln = Ho 2,Er 3,Tm 4,Yb 5,Eu 6,Gd 7,Lu 8;H₂QDA = 2,3-quinolinedicarboxylic Acid,HQA = 3-Quinolinecarboxylic Acid?and the thermal stabilities of these complexes were investigated.3.One lanthanide-transition metal heterometallic complex was obtained,[LnCu?C₂O₄??na?₂]·2H₂O?Ln =Dy 9??na=nicotinic acid?,and the thermal stability and the luminescent property of the complex was investigated.