Lanthanide Coordination Polymer

Figure 13.9 Scheme for the complexes Na[Ln(L14)(H20)4]-2H20 , and increase in luminescence intensity of a 100 xM solution of Eu-14 in H2O upon addition of Ag+ [37]. (Reproduced with permission from W.S. Liu etal., Lanthanide coordination polymers and their Ag+ -modulated fluorescence, Journal of the American Chemical Society, 126, 2280-2281, 2004. 2004 American Chemical Society.)... 

With 2,2 -bipyridine-3,3 -dicarboxylate (bpdc), also under hydrothermal conditions, a lanthanide coordination polymer [ Er4(/t3-OH)4(bpdc)4 (H20)6 2](H20)i6 is obtained wherein cubane-like [Er4(/t3-OH)4] " building blocks are assembled into a 2D network structure through the linkage of bpdc (Hu et al., 2007 Figure 101). 

The hydrothermal synthesis of the hexanuclear core-based hydroxido-lanthanide coordination polymers, [R3(BDC)3 5(0H)2(H20)2] H20 (R = Y, Yb, and Er BDC = 1,4-benzenedicarboxylate) further attests the rmiqueness of hydrothermal procedures (Weng et al., 2006). The controlled hydrolysis of lanthanide ions led to an open hexanuclear cluster core, drastically different from the commonly observed cubane or octahedral-shaped cluster cores. The hexanuclear core contains six /i3-OH-bridged R(III) ions from two asymmetric imits and adopts a chair-like configuration (R = Y, Figure 102). This hexanuclear building block is linked by the BDC ligands to form a 3D framework. 

Zhang and coworkers [176] characterized three new lanthanide coordination polymers, prepared by the reaction with l,2-bis(4-pyridyl)ethane-N,N -dioxide or with mixed N-oxide ligands in different molar ratios. TG revealed that the ligands are bound differently due to their distinctive coordination modes. 

Three physical properties ate generally targeted in the field of lanthanide coordination polymers the magnetic properties, the optical properties and the catalytic properties. 

Numerous other lanthanide coordination polymers have been designed with ligands which are neither rigid, nor unsaturated (Starynowicz and Meyer, 2000 Wu, Y. et al., 2002 Long et al., 2001 Alleyne et al., 2001 Wan et al, 2003 Feil-Jenkins et al., 1995). Some interesting results are highlighted in this section. 

Most of the above described coordination polymers have been obtained thanks to hydrothermal methods. Typically, they consists in synthesizing the coordination polymers in a Teflon-lined Parr bomb under relatively high temperatures. The reaction occurs at high temperature (typically between 150 °C and 250 °C) and elevated pressure (autogenous pressure). As far as lanthanide coordination polymers are concerned, this synthetic method seems to lead to materials exhibiting high dimensionality and low hydration rate (Cao et al., 2002b). That is why... 

Finally, the use of flexible ligands for designing ID lanthanide coordination polymers could be of interest as far as the synthesis of polymers with interesting optical properties and exhibiting a thermoplastic behavior is considered. 

Polynuclear Lanthanide Complexes and Lanthanide Coordination Polymers with Flexible Schiff-Base Ligands 286... 

The synthesis, structures, and luminescence properties of polynuclear lanthanide complexes and lanthanide coordination polymers, which are formed from multidentate oxygen and nitrogen-containing Schiff-base ligands, are described in this chapter. 

Polynuclear lanthanide complexes and lanthanide coordination polymers with distinct magnetic and luminescent properties are currently of interest for the use in applications involving the fabrication of novel materials and as probes in biological systems. However, compared to polynuclear complexes of the d-block transition metals, the design and... 

POLYNUCLEAR LANTHANIDE COMPLEXES AND LANTHANIDE COORDINATION POLYMERS WITH FLEXIBLE SCHIFF-BASE LIGANDS... 

Two kinds of salen-type Schiff-base ligands, conjugated and flexible, have been used in the synthesis of polynuclear lanthanide complexes and lanthanide coordination polymers Lanthanides Coordination Chemistry, Rare Earth Metal Cluster Complexes. The stoichiometry and structures of these complexes are dependent on the Schiff-base... 

Weng D, Zheng X, Jin L (2006) Assembly and upconversion properties of lanthanide coordination polymers based on hexanuclear building blocks with (p3-OH) bridges. Eur J Inorg Chem 2006 4184—4190... 

Wang H-S, Zhao B, Zhai B et al (2007) Syntheses, structures, and photolimiinescence of one-dimensi(mal lanthanide coordination polymers with 2,4,6-pyridinetricarboxylic acid. Cryst Growth Des 7 1851—1857... 

Sun Y-G, Yu W, Wang L et al (2010) Synthesis, structures, and luminesctaice of lanthanide coordination polymers constructed from benzimidazole-5,6-dicarboxylate and oxalate ligands. Inorg Chem Commun 13 479-483... 

Yang X, Rivers JH, McCarty WJ et al (2008) Synthesis and structures of luminescent ladderlike lanthanide coordination polymers of 4-hydroxybenzenesulfonate. New J Chem 32 790... 

Wang P, Ma J-P, Dong Y-B et al (2007) Tunable luminescent lanthanide coordination polymers based on reversible solid-state ion-exchange monitored by ion-dependent photo-induced emission spectra. J Am Chem Soc 129 10620-10621... 

Miyata K, Konno Y, Nakanishi T et al (2013) Chameleon luminophore for sensing temperatures control of metal-to-metal and energy back transfer in lanthanide coordination polymers. Angew Chem Int Ed 52 6413-6416... 

As mentioned above, design of coordination structures of lanthanide complexes enable precise manipulations of the electron transitions in f orbitals. The geometrical, vibrational, and steric structures of lanthanide complexes are directly linked to luminescence properties such as emission quantum yield, radiative, and nonradiative rate constants. The control of the coordination structures of lanthanide complexes is expected to provide desirable emission properties. Lanthanide polynuclear complexes and coordination polymers have been also studied from the viewpoint of thermostability of complexes. However, the correlation between coordination structures and photophysical properties of lanthanide complexes has been scarcely investigated, and the optimum coordination environment for strong-luminescent properties has been still unclear. Additionally, lanthanide coordination polymer with both high thermostability and strong-luminescent properties has not been previously reported. 

In this thesis, the control of coordination structures and functionalization of luminescent lanthanide(lll) complexes with LVF hfa and phosphine oxide ligands were investigated. In particular, the author constructed (1) lanthanide coordination polymer with thermostability and thermosensing ability and (2) lanthanide complexes with novel asymmetric coordination structures to improve their emission quantum yields. 

Luminescence Properties of Thermostable Lanthanide Coordination Polymers with Intermolecular Interactions... 

Here, the author considers that the introduction of low-vibrational frequency (LVF) ligands as a linker part in the polymer chains would result in the preparation of a lanthanide coordination polymer with strong luminescence properties. Strongly liuninescent lanthanide complexes composed of LVF hfa and bidentate phosphine oxide ligands have been described in former chapters. The author also proposes that the introduction of aromatic aryl groups in the linker part of lanthanide coordination polymer is effective for the construction of thermostable luminophores with intermolecular interactions, such as CH/F, n-n, and CWn interactions. 

Chameleon Luminophore for a Wide Range Temperature-Sensor Composed of Lanthanide Coordination Polymers... 

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