Mechanism for the Sensitized Luminescence of a Lanthanide Ion Macrocycle Appended to a Cyclodextrin

Abstract

Aromatic hydrocarbons trigger a green luminescence on their association to a β-cyclodextrin (CD) modified with a Tb3+ diethylenetriaminepentaacetic acid (DTPA) macrocycle strapped across the bottom of the CD cup, [β-CD∪2(Tb⊂DTPA)]. The mechanism of this enhanced luminescence response is investigated with biphenyl as the aromatic hydrocarbon. Time-resolved emission spectroscopy reveals that excitation energy at the Tb3+ ion appears 12 μs after light is absorbed by biphenyl included within the CD cup. Excitation spectra are consistent with a photophysical mechanism comprising absorption-energy transfer-emission (AETE) from the aromatic hydrocarbon bound to the cavity of CD to the DTPA-encapsulated Tb3+ ion. A comparison of the luminescence decay kinetics for biphenyl associated to [β-CD∪2(Tb⊂DTPA)] and [β-CD∪2(Gd⊂DTPA)] complexes indicates that the pathway for the AETE process is absorption to the singlet excited state followed by intersystem crossing to the triplet, from which energy is transferred to the lanthanide ion.

Supramolecular Coordination Chemistry and Functional Microporous Molecular Materials

“…30,[80][81][82][83][84][85][86][87] Even fewer have focused on such behavior in the solid state. 28,31,35,38 A potentially significant advantage of a solid-state or materials approach over, for example, an approach based on a monolayer of receptor molecules, is the higher guest-uptake capacity available.…”

A kinetic study on energy transfer between guest aromatic species and rare earth charge-compensating cations within zeolites

“…[13][14][15] A similar effect has been demonstrated in micellar systems 31,32 as well as supramolecular systems. 15,20,33 A comparison is made for the first-order energy transfer rate constants in the present zeolite-adsorbed system with various media previously investigated, as given in Table 1. Although the rate of ET is remarkably fast, less than a nanosecond in rare-earth chelates, on the one hand, and very slow in homogeneous media, on the other hand, intermediate rate constants comparable to those observed in micellar systems were obtained for the ET in the Tb 3+ -Y zeolite.…”

Luminescence of Eu3+ ions in hybrid polymer‐inorganic composites based on poly(methyl methacrylate) and zirconia nanoparticles

“…The establishment of a ‘guest–host’ system may significantly increase the luminescent properties of the phosphor due to the partial displacement of the energy levels of ions and indirect excitation using the ‘antenna effect.’ Effective chelate compounds are selected as modification agents of organic matrices. Such chelates can be flavins, pyridines, lipofuscin, polycarboxylic acids, and β‐diketones . Oxide ceramics are used as inorganic matrices, because they have a wide band gap, a high refractive index, and highly transparent in the range from UV to near IR .…”

“…Such chelates can be flavins, pyridines, lipofuscin, polycarboxylic acids, and β-diketones. [36][37][38] Oxide ceramics are used as inorganic matrices, because they have a wide band gap, a high refractive index, and highly transparent in the range from UV to near IR. [39,40] These characteristics have a big impact on the strength of the crystal lattice oscillations.…”