Synthesis, Characterization And Fluorescence Properties Of Rare Earth And Cobalt Cluster Conjugated Rare Earth Linked Complexes Containing Terpyridine

In this paper, the ligands of 4-(4-bromophenyl)-2,2':6',2"-terpyridine (L1) and 4-(4-trimethylsilyl phenylacetylene)-2,2':6',2"-terpyridine (L2) were prepared according to the literature. Additionally, the reactions of L1 and L2 with rare earth nitrates and Co2(CO)8 were carried out to give series of rare earth and cobalt clusters conjugated rare earth linked complexes, respectively.During this work, a total of nineteen new complexes were obtained. All complexes were characterized by C/H analysis, IR,1H NMR. Several of them were characterized by MS, 13C NMR and TG-DSC. In addition, the structures of complexes 1a and 1f were confirmed by X-ray single crystal diffraction analysis. Furthermore, the electrochemical and luminescent properties of some complexes were determined by UV-vis, fluorescence spectroscopy and CV analysis.Firstly, the reactions of Nd(NO3)3·xH2O, Yb(NO3)3·xH2O, Eu(NO3)3·xH2O, Er(NO3)3·xH2O, Tb(NO3)3·xH2O, Ce(NO3)3·6H2O, La(NO3)3·6H2O, Sm(NO3)3·xH2O and Dy(NO3)3·xH2O with ligand L1 afforded nine complxes (1a～1i) containing terpyridine ligand, respectivly. The crystal structures of 1a and 1i show that L1, three NO3- and one CH3OH coordinated to the rare earth center and the coordination number is ten. The fluorescence spectroscopies of complxes 1a-1c, 1e,1h and 1i show that the characteristic luminescence of Eu3+, Tb3+, Sm3+, Dy3+ in the visible light range and Nd3+,Yb3+ in the near-infared light range can be sensitized by ligand L1, respectively. Secondly, the reactions of Nd(NO3)3·xH2O, Yb(NO3)3·xH2O, Eu(NO3)3·xH2O, Er(NO3)3·xH2O, Tb(NO3)3·xH2O and Ce(NO3)3·6H2O with ligand L2 afforded six complxes (2a-2f), respectivly. The fluorescence spectroscopies of complxes 2a-2c and 2e show that ligand L2 can sensitized the luminescence of Eu3+ and Tb3+, but also sensitized the characteristic near-infared luminescence of Nd3+, Yb3+.Thirdly, the alkyne-bridging Co2C2 tetrahedral cluster 3 containing terpyridine ligand was obtained by reactions of Co2(CO)8 with L2. And its electrochemical property was measured by CV method.Finally, the 3d-4f type cobalt cluster conjugated rare earth linked complexes (4a-4c) were obtained by reactions of 2a-2c with Co2(CO)8, respectively. Their luminescence and electrochemical properties were determined by fluorescence spectroscopy and CV methods.