Thermally stable luminescent lanthanide complexes in zeolite L

et al. 2010

Angewandte Chemie

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One-dimensional channel materials as formed by some zeolites and mesoporous silicas are attractive hosts for the preparation and investigation of hierarchically organized inorganic-organic hybrid materials, presenting a successive ordering from the molecular up to the macroscopic scale. [1][2][3][4] We have been using zeolite L (ZL) as a host in most of our experiments. ZL crystals feature strictly parallel channels arranged in a hexagonal symmetry. The size and aspect ratio of the colorless crystallites can be tuned over a wide range. Their one-dimensional channels can be filled with suitable guests. Geometrical constraints imposed by the host structure lead to supramolecular organization of the guests in the channels. The supramolecular organization of dyes inside the ZL channels is the first stage of organization. It allows light harvesting within the volume of a dye-loaded ZL crystal and also allows radiationless energy transport to either the cylinder ends or to the center of the channel. One-dimensional excitation-energy transport has been observed in these guest-host materials.[5] The second stage of organization is the coupling of an external acceptor or donor stopcock fluorophore to the ends of the ZL channels, which can then trap or inject electronic excitation energy. The third stage of organization is achieved by interfacing the material to an external device through a stopcock intermediate. [1,3]

“…Tb 3+ (bpy) n -ZL and Eu 3+ (tta) n -ZL were prepared according to reference [17]. Compound 1 was synthesized and characterized according to the procedure reported in reference [16a].…”

Section: Methodsmentioning

confidence: 99%

Orienting Zeolite L Microcrystals with a Functional Linker

et al. 2010

Angewandte Chemie

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“…[8] Luminescent hybrid materials based on Ln 3 + complexes in matrices have long been in the focus of intensive study not only because they are of fundamental interest, but also because they show great potential for different applications. [9][10][11][12][13][14][15] The hybrid materials typically show enhanced stability and improved luminescence with respect to the pristine materials [16][17][18] Sol-gel-derived materials are highly promising matrices for designing new luminescent materials due to attractive characteristics such as highly controlled purity, versatile shaping and patterning, mechanical, thermal, and chemical stability, and biocompatibility. [19][20][21] Zeolites have also been employed to prepare lanthanide-based organic-inorganic hybrid materials because of their characteristic nanoscopic periodicity and their well-defined pore channels.…”

Section: Introductionmentioning

confidence: 99%

Luminescent Hybrid Materials Based on Laponite Clay

et al. 2014

Chemistry A European J

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The spectroscopic behavior of ionic Eu(3+) or Tb(3+) complexes of an aromatic carboxyl-functionalized organic salt as well as those of the hybrid materials derived from adsorption of the ionic complexes on Laponite clay are reported. X-ray diffraction (XRD) patterns suggest that the complexes are mainly adsorbed on the outer surfaces of the Laponite disks rather than intercalated within the interlayer spaces. Photophysical data showed that the energy-transfer efficiency from the ligand to Eu(3+) ions in the hybrid material is increased remarkably with respect to the corresponding ionic complex. The hybrid material containing the Eu(3+) complex shows bright red emission from the prominent (5) D0 →(7) F2 transition of Eu(3+) ions, and that containing the Tb(3+) complex exhibits bright green emission due to the dominant (5) D4 →(7) F5 transition of Tb(3+) ions.

“…[14] We and others observed considerable improvement of thermal-and photostability of lanthanide complexes when embedding them in the channels of zeolite L (ZL). [15][16][17][18][19][20][21] Oriented Ln 3+ doped ZL films with tunable emission colors have been synthesized by using functional linkers that can coordinate and sensitize Ln 3+ . [22,23] Increasing effort has been focused on nanosized zeolite for a variety of reasons.…”

mentioning

confidence: 99%

Luminescence Enhancement after Adding Stoppers to Europium(III) Nanozeolite L

et al. 2014

Angew Chem Int Ed

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107

Stopper molecules attached to nanozeolite L (NZL) boost the luminescence of confined Eu(3+)-β-diketonate complexes. The mechanism that is responsible was elucidated by comparing two diketonate ligands of different pK(a) and two aromatic imines, and by applying stationary and time resolved spectroscopy. The result is that the presence of the imidazolium based stopper is favorable to the sustainable formation of Eu(3+)-β-diketonate complexes with high coordination by decreasing the proton strength inside the channels of NZL. A consequence is that strongly luminescent transparent films can be prepared using aqueous suspension of the stopper modified composites.