Lanthanide-Containing Molecular and Supramolecular Polymetallic Functional Assemblies

Tuning the Decay Time of Lanthanide‐Based Near Infrared Luminescence from Micro‐ to Milliseconds through d→f Energy Transfer in Discrete Heterobimetallic Complexes

“…[2a] The possible simultaneous occurrence of these different mechanisms in the same complex, combined with the extreme difficulty to separate exchange from multipolar contributions in Ligand!Ln III energy transfer, limit the molecular programming and tuning of NIR luminescence. [14] In this context, the alternative use of a d-block complex as a donor, well-separated from the lanthanide acceptor, offers the potential for a rational approach, since multipolar electrostatic interactions (with or without phonon-assistance) become the only vectors for intramolecular nd!4f energy transfer processes. [10,[12][13][14] The first systems matching this criterion took advantage of the intense charge-transfer transitions, often mixed with d-d transitions, occurring in the visible spectral range of redox-active d-block complexes, to efficiently collect photonic energy.…”

“…[14] In this context, the alternative use of a d-block complex as a donor, well-separated from the lanthanide acceptor, offers the potential for a rational approach, since multipolar electrostatic interactions (with or without phonon-assistance) become the only vectors for intramolecular nd!4f energy transfer processes. [10,[12][13][14] The first systems matching this criterion took advantage of the intense charge-transfer transitions, often mixed with d-d transitions, occurring in the visible spectral range of redox-active d-block complexes, to efficiently collect photonic energy. Intersystem crossing (isc) followed by multipolar nd!4f energy transfer complete the energy funneling processes leading to the lanthanide-based NIR emission.…”

The First Self‐Assembled Trimetallic Lanthanide Helicates Driven by Positive Cooperativity

“…[1] For the lanthanide ions (Ln III ), the 4f orbitals are screened from external perturbations by outer filled 5s 2 and 5p 6 shells, [2] and the electronic properties of their complexes can be rationally tuned by weak crystal-field effects resulting from the precise control of the coordination sphere; [3] a crucial point for the implementation of specific functions. [4] Sophisticated monometallic lanthanide complexes have been thus designed for operating as 1) efficient catalysts for asymmetric organic transformations, [5] 2) contrast agents that possess two vacant coordination sites for magnetic resonance imaging (MRI), [6] 3) luminescent probes for sensing base-pairing in oligonucleotides, [7] and 4) magnetically addressable metallomesogens. [8] An increased density of magnetic or optical probes in polymetallic f ± f complexes offers new perspectives for programming molecular devices in that several lanthanide ions can be selectively introduced into the final architectures.…”

“…Emission spectra of [Eu 3 (L7) 3 ](CF 3 SO 3 ) 9 (H 2 O) 4 recorded under various conditions: a) solid state, 10 K, excitation via the ligand-centered 1 pp* levels (n Ä ex 24 016 cm À1 ), b) solid state, 10 K, selective excitation of site I (n Ä ex 17 211 cm À1 ), c) solid state, 10 K, selective excitation of site II (n Ä ex 17 238 cm À1 ), d) solid state, 295 K, excitation via the ligand-centered 1 pp* levels (n Ä ex 27 778 cm À1 ), and e) solution (acetonitrile 10 À3 m), 295 K, excitation via the ligand-centered 1 pp* levels (n Ä ex 27 397 cm À1 ). Table S9 in the Supporting Information).…”

Synthesis and characterization of monoazathiacrown ethers as ionophores for polymeric membrane silver-selective electrodes

“…For selective recognition, an efficient molecular receptor which has high potential as a complexing agent for a target heavy metal is required as sensing element [2]. Nowadays many compounds have been designed and synthesized to form remarkably stable and selective complexes with transition metal ions such as Schiffbases [3], podands [4], cyclams [5] and calixarenes [6]. Among them crown ethers containing nitrogen and sulfur donor atoms (i.e.…”