Crystal Engineering of New Functional Coordination Polymers of Lanthanide-Multicarboxylates
概要
Designs and syntheses of new series of lanthanide coordination polymers (LnCPs) using mixed phthalate (phth2-) and one of the following dicarboxylates, i.e. terephthalate (bdc2-; Chapter 3), adipate (ad2-; Chapter 4), azobenzene-4,4ʹ-dicarboxylate (abdc2-; Chapter 5) and (ΔLLL)2-[Co3(ʟ-cys)6]3- metalloligand (Chapter 6), are reported. The effects of the mixed ligands on the fabricated framework structures and their photoluminescence as well as thermogravimetric property, and water-vapor adsorption/ desorption are presented and discussed.
The use of two rigid and good sensitizing phth2- and bdc2- is reported in Chapter 3. The combination of the two ligands led to three-dimensional [Ln(bdc)0.5(phth)(H2O)2], where LnIII = EuIII (VIa), GdIII (VIIa), TbIII (VIIIa), HoIII (Xa), ErIII (XIa) and TmIII (XIIa). The phth2- linker links the discrete {LnIIIO8} units into the two-dimensional [Ln(phth)(H2O)2] sheets, which are then pillared by bdc2- leading to the three-dimensional framework. The presence of the two good sensitizing phth2- and bdc2- evidently changed the temperature-dependent photoluminescent behaviors of the monometallic VIa and VIIIa from those of [Ln2(phth)3(H2O)] (LnIII = EuIII and TbIII). Rendered by the TbIII-to-EuIII energy transfer, the bimetallic [EuxTb1-x(bdc)0.5(phth)(H2O)2] (XVa-XVIIa) exhibited sensitive temperature-dependent photoluminescent behaviors in physiological and high temperature ranges.
The use of the flexible and non-sensitizing ad2- together with phth2- is presented in Chapter 4. Two new series of three-dimensional [Nd2(ad)(phth)2(H2O)4] (IVb) and two-dimensional [Ln(ad)0.5(phth)(H2O)2], where LnIII = EuIII (VIb), GdIII (VIIb), TbIII (VIIIb), DyIII (IXb), ErIII (XIb) and TmIII (XIIb), were obtained. The difference in framework dimensionality is rationalized. The phth2- links the adjacent LnIII ions to form the edge-sharing {Ln2O16} dimers and then creates the two-dimensional sheet in IVb and one-dimensional chain in VIb-IXb and XIb-XIIb. These two- and one-dimensional structures are then pillared by ad2- with different molecular conformations leading to higher dimensional framework. Despite containing only phth2- sensitizer, the intense photoluminescence of VIb and VIIIb was revealed. The high temperature sensing performance of the bimetallic [EuxTb1-x(ad)0.5(phth)(H2O)2] (XVb-XVIIb) was studied in comparison to the [EuxTb1-x(bdc)0.5(phth)(H2O)2] (XVa-XVIIa).
The synthesis and characterization of a new series of two-dimensional [Ln(abdc)0.5(phth)(H2O)2]∙2H2O, where LnIII = EuIII (VIc), GdIII (VIIc), TbIII (VIIIc), DyIII (IXc), HoIII (Xc), ErIII (XIc) and TmIII (XIIc), is included in Chapter 5. They were fabricated from the rigid and good sensitizing phth2- and the partially flexible and non-sensitizing abdc2-linkers. The structural motifs in VIc-XIIc are similar to VIb-XIIb and their framework topologies are identical even though their space groups are different. The assembly of these two-dimensional sheets results in the infinite one-dimensional channels with window opening of ca. 3.8 x 10.9 Å2. Unlike LnCPs in the previous Chapters, VIc-VIIIc, especially VIIc (GdIII), showed no photoluminescent emission. This is explained by the energy transfer from phth2- to the co-existing non-sensitizing abdc2-.
The combination of the organic phth2- and (ΔLLL)2-[Co3(ʟ-cys)6]3- metalloligand; where ʟ-cys2-= ʟ-cysteinate, is reported in Chapter 6. This combination led to new series of chiral three-dimensional CoIII-LnIIICPs, i.e. (ΔLLL)4-[Ln3Co6(ʟ-cys)12 (phth)1.5(H2O)4]∙nH2O (IIId-XIVd; LnIII = PrIII-LuIII). These isostructural frameworks are constructed by the infinite linkage between {LnIIIO8} and (ΔLLL)2-[Co3(ʟ-cys)6]3- into three-dimensional frameworks. Their framework structures are also compared with those of four different series of LnCPs containing only (ΔLLL)2-[Co3(ʟ-cys)6]3- metalloligand, i.e. the two-dimensional (ΔLLL)4-[Ln2Co6(ʟ-cys)12(H2O)7] ‧ nH2O (Ie-IIIe; LnIII = LaIII-PrIII), the two-dimensional (ΔLLL)4-[Nd2Co6(ʟ-cys)12(H2O)9] ‧ nH2O (IVe), the two-dimensional (ΔLLL)2-[LnCo3(ʟ-cys)6(H2O)4]‧ nH2O (Ve-Xe; LnIII = SmIII-HoIII), and the three-dimensional (ΔLLL)2-[LnCo3(ʟ-cys)6(H2O)4] ‧ nH2O (XIIIe-XIVe; LnIII = YbIII-LuIII). Roles of phth2- in IIId-XIVd is discussed. The water-vapor capacities in IXd (DyIII) and XIIId (YbIII) were also investigated.