OAc^–-Dependent Self-Assembly of Luminescent Homoleptic [Ln₉(OH-Salen)₅(OH)₄(OAc)₁₀] and {[Ln₆(OH-MeO-Salen)₅(OH)(OAc)₂(H₂O)₂]·(OAc)} Complexes

Abstract

Two series of OAc–-dependent unique homoleptic nonanuclear [Ln9(L1)3­(HL1)2­(μ3-OH)4­(OAc)10] (1–7) and hexanuclear {[Ln6(L2)4(HL2)­(μ3-OH)­(OAc)2­(H2O)2]­·(OAc)} (8–14) are obtained from the self-assembly of the partially deprotonated OH-H2Salen ligand H 3 L 1 (N,N′-bis­(salicylidene)­(propylene-2-ol)-1,3-diamine) or OH-MeO-H2Salen ligand H 3 L 2 (N,N′-bis­(3-methoxysalicylidene)­(propylene-2-ol)-1,3-diamine) with Ln­(OAc)3 (Ln = La, Eu, Tb, Gd, Nd, Yb, or Er), respectively. The result of their photophysical properties shows that the sensitization for single-component near-white-light of complex 2, efficient Eu3+-centered red-light (ΦL Eu = 13.4%) of complex 9, or or Tb3+-centered yellowish-green-light (ΦL Tb = 8.1% and 21.3%) of complexes 3 and 10, and Nd3+- or Yb3+-centered NIR luminescence (η = ΦL Ln/ΦLn Ln = 67–75% and 76–85%) for complexes 5–6 and 12–13, arose from the ligands’ 3π–π* excited state, due to effective intramolecular energy transfer and multiple Ln3+-to-Ln3+ electron-communications.

Two Luminescent High-Nuclearity Lanthanide Clusters Ln48 (Ln = Eu and Tb) with a Nanopillar Structure

“…For Eu 48 at 295 K, the lifetimes of the emissions at 594 and 615 nm are 287 and 284 μs (Figure a and b), and the lifetime values of the emission peaks at 488 and 543 nm of Tb 48 are 875 and 905 μs (Figure c and d) at room temperature, respectively. The microsecond magnitude lifetimes of Eu 48 and Tb 48 are coincident with those of other europium and terbium complexes. , The solid-state absolute quantum yields of Eu 48 and Tb 48 are 15.52% and 4.68% at 77 K and 8.40% and 3.11% at 295 K, respectively. The absolute quantum yields derive from the appropriate energies of the triplet state levels of the corresponding monodentate carboxylic acid ligands to Eu 3+ and Tb 3+ ions …”

Regulation of the Metal Center and Coordinating Anion of Mononuclear Ln(III) Complexes to Promote an Efficient Luminescence Response to Various Organic Solvents

“…The Gd 1 were dissolved in CH 3 OH solution (10 –6 mol/L) for excitation (350 nm) and emission (420 nm) tests in Figure S10. Also, the measurement of luminescence shows that the energy-transfer pathway is from the ligand to metal ions (Dy­(III), Tb­(III), Eu­(III)) . When 1 was excited using light with a wavelength of 313 nm, it exhibited two broad emission peaks with a wavelength of 435 nm and an emission peak with a wavelength of 741 nm (Figure a).…”

The Effect on the Luminescent Properties in Lanthanide-Titanium OXO Clusters

“…In an effort to overcome these weaknesses, it was found recently that the utilization of the carboxylate bridges to link the metal ions in the LTOCs can effectively enhance their structural and thermal stability. ,, And therefore, the study of the properties of LTOCs, such as luminescence and photoelectrocatalysis, becomes a reality. To our surprise, although research has experimentally demonstrated that, in comparison with pure lanthanide-based metal clusters, formation of Eu–Ti–O species in the LTOCs can significantly lower the energy required for Ln 3+ photoluminescence sensitization, and hence the LTOCs are regarded as excellent candidates for luminescent materials and expected to exhibit unique and intriguing luminescence properties, investigation of luminescence properties of the LTOCs, especially luminescence quantum yield and lifetime, is quite limited. The main reasons are that (1) the factors that influence luminescence properties of the LTOCs are not clear so far and (2) the introduction of lanthanide ions into the clusters often results in the lanthanide ions being coordinated by small molecules, such as water and alkanol molecules, which leads to the emissive states of lanthanide ions in the LTOCs easily quenched by nonradiative O–H vibration and thus remarkably decreasing the luminescence quantum yield and lifetime from lanthanide centers.…”