Highly Luminescent Eu³⁺and Tb³⁺Macrocyclic Complexes Bearing an Appended Phenanthroline Chromophore

Abstract

A two-component ligand system (1) containing 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid (DO3A) as the hosting unit for the lanthanide cations and an appended asymmetrically functionalized 1,10-phenanthroline (phen) as the chromophore was synthesized. The 1:1 complexes with Eu(3+), Gd(3+), Tb(3+), and Yb(3+) have been prepared and studied in aqueous solution. For Gd.1, a relaxivity value of 2.4 mM(-1) s(-1) has been measured at 20 MHz and 25 degrees C, which indicates that there are no water molecules in the first coordination sphere of the metal ion. The analysis of high resolution (1)H NMR spectra of Yb.1 supports this view and suggests the direct involvement of the phen moiety in the coordination of the metal ion. For Eu.1 and Tb.1, the absorption and luminescence spectra, the overall luminescence efficiencies, and the metal-centered (MC) lifetimes were obtained; coordination features were also determined by comparing luminescence properties in water and deuterated water. For Eu.1 and Tb.1, the overall emission sensitization (se) process in air-equilibrated water was found to be notably effective with phi(se) = 0.21 and 0.11, respectively. A detailed study of the steps originating from light absorption at the phen unit and leading to MC sensitized emission was performed.

Zn2+‐Responsive Bimodal Magnetic Resonance Imaging and Fluorescence Imaging Agents and Their Interaction with Human Serum Albumin

“…On the one hand, the nonradiative deactivation of the excited state is highly constrained upon the substitution of the two coordinated H 2 O molecules of GdL1Zn with HSA. [34] On the other hand, as reflected by the HSA-based fluorescence quenching upon the addition of GdL1Zn, efficient energy transfer most likely occurs from the HSA domain to GdL1Zn upon the formation of a GdL1Zn-HSA adduct through direct HSA-Zn coordination.…”

Wet Adsorption of a Luminescent EuIII complex on Carbon Nanotubes Sidewalls

“…We assume that this weight loss is due to pyrolysis of the [Eu(DBM) 3 Notably, the two-step degradation mechanism of the Eu III -complex occurs at lower temperatures for the hybrid material [Eu(DBM) 3 (Phen)] · ox-SWNT probably due to the loss of the crystalline properties of the Eu III -containing phase (see also HR-TEM discussion). [42,54,55] and the dibenzoylmethane (DBM) [56,57] ligands, respectively. On the contrary, in the near infrared region (NIR), the detection of the typical nanotube-centered absorption tail [58,59] was not clearly observed due to the heterogeneity and opacity of the samples.…”

“…[24,40,41] Due to their exceptional luminescence properties, complexes of lanthanide trivalent ions, Ln III , have attracted a lot of interest in a large spectrum of important electronic and bio-technological fields. [42,43] For instance, emitting complexes of Tb III and Eu III ions are employed as markers in fluoroimmunoassay [44,45] where a quantitative estimate of antigens in biological matrices is needed. Due to their strong and long-lived luminescence, the background signal from the biological matrix can be circumvented making particularly easy the detection of the desired analytical signal.…”

Photoluminescent Peptide Nanotubes

“…Note that when more than two kinds of phosphors were present in proximity to each other, only the emission from the phosphor with the lowest excited state energy (red emission of Eu, in the present study) would be observed, according to Kasha's rule. [24,25] In order to show the color tunability of our photoluminescent peptide nanotubes, we determined the coordinates of our luminescent peptide-nanotube complexes with various compositions in the Commission Internationale de L'Eclairage (CIE) chromaticity diagram, and investigated the relationship between the composition of peptide nanotubes and their luminescent color by regression analysis (Fig. 6b).…”