Rethinking Sensitized Luminescence in Lanthanide Coordination Polymers and MOFs: Band Sensitization and Water Enhanced Eu Luminescence in [Ln(C₁₅H₉O₅)₃(H₂O)₃]_n (Ln = Eu, Tb)

Abstract

A coordination polymer [Ln(C15H9O9)3(H2O)3]n (1-Ln = Eu(III), Tb(III)) assembled from benzophenonedicarboxylate was synthesized and characterized. The organic component is shown to sensitize lanthanide-based emission in both compounds, with quantum yields of 36% (Eu) and 6% (Tb). Luminescence of lanthanide coordination polymers is currently described from a molecular approach. This methodology fails to explain the luminescence of this system. It was found that the band structure of the organic component rather than the molecular triplet state was able to explain the observed luminescence. Deuterated (Ln(C15H9O9)3(D2O)3) and dehydrated (Ln(C15H9O9)3) analogues were also studied. When bound H2O was replaced by D2O, lifetime and emission increased as expected. Upon dehydration, lifetimes increased again, but emission of 1-Eu unexpectedly decreased. This reduction is reasoned through an unprecedented enhancement effect of the compound's luminescence by the OH/OD oscillators in the organic-to-Eu(III) energy transfer process.

Controllable Synthesis of Porphyrin‐Based 2D Lanthanide Metal–Organic Frameworks with Thickness‐ and Metal‐Node‐Dependent Photocatalytic Performance

“…The 1 TCPP and 3 TCPP were calculated as 18260 cm −1 and 12310 cm −1 respectively (Supporting Information, Table S4). According to Reinhoudt's empirical rule, the effective intersystem crossing process would be occurred when the energy gap between 1 TCPP and 3 TCPP of the ligand more than 5000 cm −1 . While the energy gap of H 2 TCPP was 5950 cm −1 , so H 2 TCPP possesses high intersystem crossing efficiency.…”

Photoluminescence of Visible and NIR‐Emitting Lanthanide‐Doped Bismuth‐Organic Materials

“…Time‐resolved measurements of the 7 F 1 transition showed a long‐lived decay ( τ obs ) of 1216±4 μs, and the quantum yield (Φ tot ) of this compound was calculated to be 25.5(3)%. Previously established relationships on the nature of Eu III emission using these values allows for further characterization of the photophysical properties in Bi 0.84 Eu 0.16 OM‐1 (see Supporting Information), informing of an intrinsic quantum yield (Φ Eu ) and efficiency of sensitization ( η sens ) of 50.9 and 50.1 %, respectively . Previous investigations that have examined the emissive properties of europium‐thiophenecarboxylates are limited, and even fewer of these studies have measured quantum yields for the products.…”

Zn(ii)/Cd(ii) based mixed ligand coordination polymers as fluorosensors for aqueous phase detection of hazardous pollutants

“…Luminescence in lanthanide-based LCPs is accounted for by the delivery of excitation energy through an antenna effect from the triplet excited states to the emissive states in lanthanides by strong photon absorbing ligands with efficient intersystem crossing (ISC). [24][25][26][34][35][36][37][38][39][40][41][42][43] To enliven the luminescence in the CP/MOF, aromatic di or polycarboxylate with a rigid backbone along with imidazole/pyridine ligands has been commonly used and explored for various applications including the detection of nitroorganic compounds. The various aspects and effects contributing to the luminescence in CPs/MOFs have been schematically demonstrated in Scheme 1.…”

“…LMOF (101) possesses luminescence sensing ability for Fe 3+ cations in water with a quenching constant of 4.78 × 10 5 M −1 and an LOD value of 1.94 × 10 −5 M. 136 A series of mixed ligand Zn-based LCPs involving aromatic dicarboxylate and N-donor ligands such as [Zn(afsba) (bbtz) 1.5 (H 2 O) 2 ]•2H 2 O} n (102), [Zn(oba) 2 (bipy) 2 ] n (103) and {[Zn 2 (L 18 ) 2 (BDC)]•2H 2 O} n (104) with hydrolytic stability have been reported. All three LCPs (102-104) showed excellent luminescence properties in water and were successfully utilized as selective sensory materials for the detection of Fe 3+ cations/chromate oxyanions (Table 2, entries[40][41][42]. The sensing mechanism for all three complexes involves the energy transfer phenomenon between the accepter analyte and donor frameworks [137][138][139].…”