| The near-infrared (NIR) luminescent properties from series of lanthanide ions, such as Nd3+, Yb3+or Er3+and their potential applications in the organic light-emitting diodes (OLED), optical communications and bio-analysis become one of the focused areas in material science. However, due to the forbidden parity from f-f transitions, the low molar absorption coefficients need the necessary chromophores ("antenna effect") to sensitize the NIR luminescence of these Ln3+ions, indirectly. On the other hand, the problems to poor mechanical property, low stability and uneven dispersion in their practical use as the optical materials must be overcome.In this thesis, in order to improve the NIR quantum efficiency of these Ln3+ions sensitized by Zn2+-based complexes based on the Salen-type Schiff-base ligands with both N2O2and O2O2groups as the energy donors, the reaction control conditions on high NIR quantum efficiency for the hetero-nuclear complexes are explored by studying the affects of anions, the molar ratio of the reactions, solvents and the introduction of ancillary ligands. Moreover, with the target Zn-Ln structure units with two terminal allyl, phenylethenyl and thienyl functional groups as the monomers, the constructions of series of Wolf Type II Zn2+-Ln3+-containing metallopolymer materials are obtained through the addition copolymerization. On the one hand, depending on the rule of "energy level match", the structure factors on Zn-Ln structure units with the high quantum efficiency (about1%) are studied. Moreover, series of novel PMMA, PS and PVK-supported Wolf Type II metallopolymer hybrid materials are obtained through the covalent-bonding. The detailed content is shown as follows:(1) On the self-assembly of Zn2+and Ln3+with Salen-type Schiff-base ligand H2L1(N, N’-bis(3-methoxy-salicylidene)cyclohexane-1,2-diamine) with both the inner cis-N2O2and the outer O2O2groups, the rules are summarized. When the reaction molar ratio of the ligand, Zn2+and Ln3+is1:1:1, the co-existence of OAc-and NOa-in alcohol-containing solvent systems, series of hetero-binuclear Zn-Ln complexes [Zn(OAc)Ln(L1)(NO3)2](Ln=Nd, Yb, Er or Gd, Ⅱ-2-5) with OAc-bridged between Zn2+and nine-coordinate Ln3+ion are obtained. While the further introduction of DMF, endows the obtainment of series of hetero-binuclear Zn-Ln complexes [Zn(OAc)Ln(L1)(NO3)2DMF](Ln=Nd, Yb, Er or Gd, Ⅱ-6-9) with OAc-bridged between Zn2+and ten-coordinate Ln3+ion. If the solvent of MeCN is used in the reaction systems, series of hetero-binuclear Zn-Ln complexes [Zn(MeCN)Ln(L1)(NO3)3](Ln=Nd, Yb, Er or Gd,11-10-13) are self-assembled, where the axial position of Zn2+is occupied by MeCN, and Ln3+are ten-coordinated from four O atoms of the O2O2moiety and six O atoms of three bidentate NO3-anions. On the other hand, under the condition of a molar ratio of2:2:1, the use of either OAc-or Cl-gives the similar series of hetero-trinuclear Zn2Ln complexes [Zn2Ln(L1)2(OAc)3](Ln=Nd, Yb, Er or Gd,11-14-17) or [Zn2Ln(L1)2(Cl)3](Ln=Nd, Yb, Er or Gd,11-18-21), respectively. Moreover, the co-existence of Cl" and NO3" also endows the obtainment of the similar series of hetero-trinuclear Zj^Ln complexes [Zn2Ln(L1)2(Cl)2(NO3)](Ln=Nd, Yb, Er or Gd,11-22-25). The results of their photophysical properties show that the hetero-trinuclear complexes exhibit relatively higher NIR quantum efficiency in comparison with the hetero-binuclear complexes, because of the plurality of more energy donors besides the reduction or avoidance of the quenching effect.(2) The further introduction of o-vanillin (HL2) as the ancillary ligand in self-assembly of ZnCl2and Ln(NO3)3with Salen-type Schiff base ligand H2L1, two series of hetero-trinuclear complexes [Zn(Cl)Ln2(L1)2(L2)(NO3)2](Ln=Nd, Yb, Er or Gd, Ⅲ-1-4) and [Zn(Cl)Ln(L1)(L2)(NO3)(MeCN)](Ln=Nd, Yb, Er or Gd, Ⅲ-5-8) are obtained by changing the molar amounts of Ln(NO3)3. If with pyridine as the ancillary ligand, hetero-nuclear complexes [Zn(Py)Ln(L1)(NO3)3](Ln=Nd, Yb, Er or Gd, Ⅲ-9-12) could be obtained, and the expected NIR quantum efficiency (about1%) is shown from the energy transfer of both the3LC and1LC of the ligands.(3) Ruled by the achievement from points (1) and (2), the introduction of two terminal allyl functional groups on the flexible Salen-type Schiff-base ligand for H2L3(N,N’-bis(5-allyl-3-methoxysalicylidene)cyclohexane-1,2-diamine), gives the products of [Zn(Py)Ln(L3)(NO3)3](Ln=La, Nd, Yb, Er or Gd, Ⅳ-1-5) complexes. Although the copolymerization with methyl methacrylate (MMA) in the presence of co-catalyst AIBN is expected, the doped hybrid materials PMMA/[Zn(Py)Ln(L3)(NO3)3])(Ln=La, Nd, Yb, Er or Gd, Ⅳ-6-12) are obtained due to the failure of radical polymerization between the terminal ally groups with MMA. Meanwhile, the thermal stability and photophysical properties of the doped hybrid materials are studied.(4) In order to overcome the limit of point (3), the new flexible Salen-type Schiff-base ligand H2L4(N,N’-bis(5-phenylethylene-3-methoxysalicylidene)cyclohexane-1,2-diamine) with two terminal phenylethylene functional groups is designed. With the obtained complexes [Zn(Py)Ln(L4)(NO3)3](Ln=La, Nd, Yb, Er or Gd, V-1-5) as the monomers, through the radical copolymerization with MMA, ST or NVK in the presence of co-catalyst AIBN, three series of Wolf Type Ⅱ metallopolymers Poly(MMA-Co-[Zn(Py)Ln(L4)(NO3)3])(Ln=La, Nd, Yb, Er or Gd, V-6-12), Poly(ST-Co-[Zn(Py)Ln(L4)(NO3)3])(Ln=La, Yb or Gd, V-13-15) and (Ln=Poly(NVK-Co-[Zn(Py)Ln(L4)(NO3)3])(Ln=La, Nd, Yb, Er or Gd, V-16-18) are successfully obtained, respectively. Also besides the check of thermal stabilities and photophysical properties, the Ln3+-based concentration quenching effect are studied, especially.(5) Through the modification of thiophene functional groups to the flexible Schiff base ligand for H2L5(N,N’-bis(5-thienyl-3-methoxysalicylidene)cyclohexane-1,2-diamine), its self-assembly with the new ligand with Zn3+, Ln3+and pyridine (Py), endows the obtainment of series of hetero-binuclear [Zn(Py)Ln(L5)(NO3)3](Ln=Nd, Yb, Er, Gd, Ⅵ-1-4). Moreover, the energy transfer and the sensitization of NIR luminescence of Ln3+ions are discussed, and their use for obtaining the conductive Zn2+-Ln3+-containing Wolf Type Ⅱ metallopolymers by electrochemical self-polymerization will be finished in the future. |
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