Two-Photon Antenna Sensitization of Curium: Evidencing Metal-Driven Effects on Absorption Cross Section in f-Element Complexes

Abstract

Two-photon-excited fluorescence spectroscopy is a powerful tool to study the structural and electronic properties of optically active complexes and molecules. Although numerous lanthanide complexes have been characterized by two-photon-excited fluorescence in solution, this report is the first to apply such a technique to actinide compounds. Contrasting with previous observations in lanthanides, we demonstrate that the two-photon absorption properties of the complexes significantly depend on the metal (4f vs 5f), with Cm­(III) complexes showing significantly higher two-photon absorption cross sections than lanthanide analogues and up to 200-fold stronger emission intensities. These results are consistent with electronic and structural differences between the lanthanide and actinide systems studied. Hence, the described methodology can provide valuable insights into the interactions between f-elements and ligands, along with promising prospects on the characterization of scarce compounds.

Arel: Investigating [Eu(H2O)9]3+ Photophysics and Creating a Method to Bypass Luminescence Quantum Yield Determinations

“…Lanthanide luminescence is used in highly sensitive time-resolved and dissociation enhanced DELFIA bioassays, − in display and lighting technology, and in lasers and telecommunication. , All applications rely on the robust, atom-like, narrow, and highly defined absorption and emission lines of the trivalent lanthanide ions. The nature of these transitions has sparked interest in applications such as bioimaging, , upconversion nanoparticles and quantum dots, − optical probes, − and phosphors, as well as studies probing the fundamental nature of the optical transitions in f-elements. − …”

Multidimensional genome-wide screening in yeast provides mechanistic insights into europium toxicity

“…6 Because Eu(III) emission originates from forbidden f−f transitions and direct electronic excitation is not efficient, the metal ion can alternatively be complexed with a light-harvesting ligand, which absorbs light and transfers the excitation energy to Eu(III). 8,9 Thus, Eu(III) complexes with chromophore-containing ligands are used as luminescent probes in bioassays. [10][11][12][13] Another interesting application of Eu(III) is in the production of anti-counterfeiting ink in Euro bank notes.…”

Expanding the Transuranic Metal–Organic Framework Portfolio: The Optical Properties of Americium(III) MOF-76

“…In short, the electronic excited states are known to shift to lower energy as a function of covalent bond formation (i.e., the nephelauxetic effect). ,, While this relationship is well-known, the underlying mechanism remains underexplored. With respect to resonance energy transfer, sensitized Am 3+ (or Cm 3+ ) emission has been demonstrated, yet most of the reported studies are in solution. , Although evidence for (inefficient) ligand-to-metal energy in an Am 3+ containing MOF was recently demonstrated, less can be said with certainty regarding the translation of solution to solid-state behavior . The MOF-76 platform can, therefore, be leveraged to study the optical properties of Am 3+ in a crystalline form and, moreover, explore how the chemistry of several Ln 3+ surrogates translates to the 5f elements.…”