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

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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.

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

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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.

Design and Synthesis of Novel Lanthanide Chelates for Use in Magnetic Resonance Imaging (MRI).
Design and Synthesis of Novel Lanthanide Chelates for Use in Magnetic Resonance Imaging (MRI).

Author: Graeme James Stasiuk

Publisher:

Published: 2010

Total Pages:

ISBN-13:

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This thesis reports a series of novel Ln-DO3A based complexes, modulation of emission intensity (Eu and Tb) has been achieved and relaxivity, r1, (Gd) has been shown. Propargyl-appended lanthanide complexes derived from DO3A, has a hydration state, q = 2. They undergo Cu(I) catalysed cycloaddition reactions with azides to form 1,2,3-triazole appended complexes: coordination of one of the triazole nitrogen atoms to the metal centre changes the local coordination environment and luminescence studies indicate a hydration state of q = 1. Propargyl-appended Ln(III) complexes show unanticipated reactivity towards NaN3 in the Cu(I) catalysed 'click' reaction yielding an unsubstituted 1,2,3-triazole. The resulting Eu(III) complex exhibits pH-responsive 1H NMR and Ln(III) luminescence behaviour in the physiological pH range, consistent with deprotonation of the NH-acidic bound triazole. The coordination mode of the NH-triazole switches from NH-triazole bound in a pyridinic manner to bound in an anionic manner as a triazolide, while retaining a q = 1. This was demonstrated in luminescent studies of Eu(III) and Tb(III) complexes with a pKa ~ 7.5. Relaxation measurements on the Gd(III) analogue show a q =1 throughout the pH range, i.e. no change in hydration state. To overcome the unanticipated reactivity of NaN3 with propargyl-appended Ln(III) complexes, p-ethynylbenzyl-appended Ln(III) complexes were synthesised. These show promise as precursors for multimeric, self-associating and d-f hybrid complexes, via the Cu(I) catalysed cycloaddition or 'click' reaction. Luminescent studies show evidence of the formation of 1,2,3-triazoles that do not bind to the Ln(III) metal centre, with a hydration state q =1. These complexes have been applied in the synthesis of multimeric, self-associating and d-f hybrid compounds. Uridine was attached to a EuDO3A chelate via four different linkers. These complexes are precursors for an accumulation and activation strategy, developed as enzyme activated contrast agents. Neutral q = 1 Eu(III) uridine-DO3A based complexes were successfully synthesised and linked via a propyl, amide or 1,2,3-triazole unit.

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

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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