Synthesis, Characterization, and Photophysical Studies of Organic-Lanthanide Complexes

Synthesis, Characterization, and Photophysical Studies of Organic-Lanthanide Complexes

Author: Ka-Leung Wong

Publisher: Open Dissertation Press

Published: 2017-01-27

Total Pages:

ISBN-13: 9781361426593

DOWNLOAD EBOOK

This dissertation, "Synthesis, Characterization, and Photophysical Studies of Organic-lanthanide Complexes" by Ka-Leung, Wong, 黃嘉良, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled SYNTHESIS, CHARACTERIZATION, AND PHOTOPHYSICAL STUDIES OF ORGANIC- LANTHANIDE COMPLEXES Submitted by Ka-Leung Wong For Degree of Doctor of Philosophy at The University of Hong Kong in August 2006 The general background and coordination chemistry of lanthanides, their characteristic luminescent properties and nonlinear luminescent properties with the applications to material science and biological systems are reviewed. The design and synthesis of lanthanide-organic complexes based on similar tripodal amide ligands N-[2-(bis{2-[(ortho- substituent -benzoyl)amino]ethyl}amino)- ethyl]benzamide (ortho substituent-C H N O ) and bidentate amide ligands di-2- 27 27 4 3 methoxy-(2-aminoethyl)benzamide (C H N O ) were described. These ligands were 20 33 3 8 found to have different coordination to the lanthanide that caused a change in the photo-physical properties. The occurrences of high order multi-photon processes are rare, especially with lanthanide complexes. Generally there is a lack of clear molecular structure in systems that have been reported in the literature, hindering our understanding of the correlation of photo-structural properties. Our complexes have been found to display two different forms of coordination, which significantly affects their photo-properties. X-Ray structure analysis showed that, one being a linear polymeric form and the other a dendritic form, the latter has been found to exhibit an additive harmonic generation process as well as the multi-photon process which is present in both types of coordination. The design and synthesis of a metal-organic network were described based on a lanthanide complex that contains mucic acid, {[Ln(Mucicate) (H O) ].5H O} (Ln 1.5 2 2 2 n = Eu and Tb), exhibiting a novel 1-D hydrophilic channel in the porous framework. The 3D framework with a hydrophilic inner surface was found to exhibit a reversible - - - - anion uptake. Upon addition of an aqueous solution of sodium salts of I, Br, Cl, CN, 2- CO, to a solid sample of the Ln complex, the luminescent intensity enhancements were observed. The anion response of the channels is believed to be due to the effect of numerous OH groups in the mucic acid, which interacts strongly with the anion through hydrogen bonding. Experimental details including instruments used for physical characterization and the photo-physical measurement for linear, multi-photon absorption induced f-f emission and nonlinear emission were presented. DOI: 10.5353/th_b3687535 Subjects: Rare earth metals Organometallic compounds - Synthesis


Lanthanide-containing Functional Materials: Exploratory Synthesis and Property Investigation

Lanthanide-containing Functional Materials: Exploratory Synthesis and Property Investigation

Author: Mawanana H. Channa R. De Silva

Publisher:

Published: 2007

Total Pages: 554

ISBN-13:

DOWNLOAD EBOOK

The research summarized in this dissertation is aimed at the design and exploratory synthesis, characterization, and property investigation of lanthanide-based functional materials. The substances prepared in this work, including small molecular complexes and nanostructured particles, are of fundamental scientific interest as well as practical significance due to the unique chemical and physical properties of the lanthanide elements. Envisioned applications include their uses as light-emitting materials in modern display technology, optical amplifiers, and high-density magnetic recording media. This research seeks to develop general methods for directing the formation of lanthanide materials, particularly as a means of influencing the physical properties of such materials. These efforts are elaborated in distinct yet related projects. In Chapter 2, exploratory synthesis, structural characterization, and photo-physical investigation of adducts of lanthanideβ-diketonates with a tridentate neutral ligand, TPTZ are described. In Chapter 3, analogous studies utilizing p, p'-disubstituted bipyridine and phenathroline type bidentate neutral ligands are detailed. The structures of the complexes have been established by single crystal X-ray diffraction. Compositional and structural differences among the various complexes are caused by different structural and electronic properties of the ligands and overall steric compactness of the coordination sphere. Red and green luminescence characteristics of Eu(III) and Tb(III) ions are observed for the corresponding complexes, upon UV excitation, consistent with the well-established ligand-mediated energy transfer and light emission mechanism. In Chapter 4, the electroluminescence properties of various europium complexes are evaluated for their potential as emissive materials in organic light-emitting diodes. The synthesis and characterization of Er-doped LaPO4 nanoparticles are described in Chapter 5 together with the preparation and studies of hybrid nanocomposites composed of nanoparticle-doped sol-gels. A single-mode waveguide system was fabricated, wherein Er-doped nanoparticles solubilized in a sol-gel matrix has shown promising performance in propagating light signals (1.54 æ̐m) without significant optical losses. In Chapter 6, synthesis, electron microscopic characterization and magnetic studies of crystalline Sm(III)- and Eu(III)-doped Fe3O4 nanoparticles are detailed. Magnetic studies suggest the ferromagnetic behavior of the lanthanide-doped Fe3O4 nanoparticles at room temperature and therefore, the significant effects of lanthanide doping.


Highly Luminescent Lanthanide Complexes with Specific Coordination Structures

Highly Luminescent Lanthanide Complexes with Specific Coordination Structures

Author: Kohei Miyata

Publisher: Springer Science & Business Media

Published: 2014-04-08

Total Pages: 100

ISBN-13: 4431549447

DOWNLOAD EBOOK

This thesis deals with strongly luminescent lanthanide complexes having novel coordination structures. Luminescent lanthanide complexes are promising candidates as active materials for EL devices, lasers, and bio-sensing applications. The organic ligands in lanthanide complexes control geometrical and vibrational frequency structures that are closely related to the luminescent properties. In most of the previous work, however, lanthanide complexes have high-vibrational frequency C–H units close to the metal center for radiationless transition. In this thesis, the luminescent properties of lanthanide complexes with low-vibrational frequency C–F and P=O units are elucidated in terms of geometrical, vibrational, and chemical structures. The author also describes lanthanide coordination polymers with both high thermal stability (decomposition point > 300°C) and strong-luminescent properties (emission quantum yield > 80%). The author believes that novel studies on the characteristic structures and photophysical properties of lanthanide complexes may open up a frontier field in photophysical, coordination and material chemistry.


Assembled Lanthanide Complexes with Advanced Photophysical Properties

Assembled Lanthanide Complexes with Advanced Photophysical Properties

Author: Yuichi Hirai

Publisher: Springer

Published: 2018-04-07

Total Pages: 115

ISBN-13: 9811089329

DOWNLOAD EBOOK

This thesis provides essential information on the systematic design of assembled lanthanide complexes for functional luminescent materials. It discusses the relationships between assembled structures and photo, thermal, and mechanical properties on the basis of crystallography, spectroscopy, and thermodynamics. The described guidelines for assembled structures will be extremely valuable, both for industrial applications and for readers’ fundamental understanding of solid-state photophysics and materials chemistry. Luminescent lanthanide complexes are promising candidates for lighting devices, lasers, and bio-probes owing to their line-like and long-lived emission arising from characteristic 4f–4f transitions. Low-vibrational and asymmetrical coordination structures around lanthanide ions have been introduced to achieve strong luminescence, using specific organic ligands. Recently, assembled lanthanide complexes including coordination polymers and metal organic frameworks have increasingly attracted attention as a new class of luminescent materials offering thermal stability and color tunability. However, improving the luminescence efficiencies of these compounds remains a challenge, and specific molecular designs to control assembled structures and yield additional physical properties have not been established. The author provides a group of bent-angled bridging ligands to boost photoluminescence efficiency, and successfully introduces for the first time glass formability and strong triboluminescence properties.


Synthesis, Characterization and Photophysical Studies of Triazine-based Lanthanide(III) Îø-diketonate Complexes

Synthesis, Characterization and Photophysical Studies of Triazine-based Lanthanide(III) Îø-diketonate Complexes

Author: Wai Sum Lo

Publisher:

Published: 2016

Total Pages: 279

ISBN-13:

DOWNLOAD EBOOK

As Sm(III) is dual-emissive - emitting in both the visible and NIR regions, the NIR photophysical properties were investigated. Originating from the same emitting state as the visible luminescence transitions, the NIR transitions were studied and compared. In addition to solvatochromic studies, this chapter discusses the validity of the energy gap law in estimating the extent of quenching by high energy oscillators and thus provide a blueprint for maximizing the intrinsically weak NIR luminescence by manipulating the coordination environment. NIR luminescence from the ytterbium(III) complex was also presented, as the energy transfer mechanism of Yb(III) has always been sort of an enigma due to the large energy difference between the Yb(III) only excited state and the donating state of common antennae. Chapter five focuses on the syntheses of a multidentate water-soluble pocket for lanthanide(III) complexes. The ligand system extends the aforementioned studies by using a single multi-chelate in place of multiple tri-/bi-dentate ligands as an effort to increase the stability of the complexes in solution state and thus creates a platform for exploring the non-triplet ILCT energy transfer pathway for lanthanide(III) luminescence sensitization in water to expand the scope of potential applications.


Synthesis and Characterization of Lanthanide Complexes with Phenalenide and Aromatic-fused Cyclopentadienyls as Ligands

Synthesis and Characterization of Lanthanide Complexes with Phenalenide and Aromatic-fused Cyclopentadienyls as Ligands

Author:

Publisher:

Published: 2002

Total Pages:

ISBN-13:

DOWNLOAD EBOOK

The synthesis of yttrium phenalenide complexes 129-132 was achieved by salt metathesis reactions between ligand anions and YCI3. Ytterbium phenalenide complexes 133-137 were synthesized by protonolysis reactions between neutral ligands and Yb[N(SiMe3)2]2(THF)2. The solid state structure of (Pni1Bu)2Yb(THF) 136 reveals a unique n3 bonding pattern, however the electrons of the phenalenide ligand remain delocalized even when bonded to the metal center. Mono-alkyl complexes (PCpR)2Y(CH2SiMe3)(THFSiMe3)(THF) 147-149 (R = Me. Ph. H) and bis-alkyl complexes (PCp*)Y(CH2SiMe3)2(THF) 150 and (sCp)Y(CH2SiMe3)2(THF) 152 were synthesized by direct protonolysis reactions between Y(CH2SiMe3)3(THF)2 and neutral ligands. When treated with phenylsilane, complex 148 generated the crowded hydride dimer [(PCpPh)2Y(u-H)]2 161. Complexes 150 and 152 undergo acid-base. metallation. insertion reactions and polymerization of small substrates. A variable temperature `H NMR study of 150 and 152 at low temperature reveals an equilibrium between 150/152-THF and 1501152. The THF-free complexes. 150/152-THF. appear to undergo inversion of a pyramidal ground state structure to generate a C2 symmetric intermediate. The X-ray structures of 136, 147, 150. 152, (sCp)Y(CH2SiMe3)2(bipy) 154, 161. [PCp*Y(CCSiMe3)(THF)]2(u2-CCSiMe3)2] 167, acetylide cluster 169 and bis-(Me3Si)2Cp yttrium chloride dimer 176 were determined and structural features discussed.