Fine-Tuned Visible and Near-Infrared Luminescence on Self-Assembled Lanthanide-Organic Tetrahedral Cages with Triazole-Based Chelates

Abstract

The construction of well-defined lanthanide complexes emitting in both the visible and near-infrared regions is of great importance due to their widespread applications in phosphors, light-emitting diodes, biosensors/probes, optical communications, etc. In comparison to the well-known mononuclear and dinuclear lanthanide complexes, multinuclear lanthanide supramolecular edifices with bright luminescence are still scarce. Herein, we report the coordination self-assembly of strongly luminescent lanthanide-organic tetrahedral Ln4L4 cages with a series of tris­(tridentate) ligands based on the triazole chelates. Among them, the new ligand L3 with triazole-pyridine-triazole (TPT) chelates manifests an excellent sensitization toward all of the lanthanide ions (Ln = Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb) that emit in both the visible and near-infrared regions, with a record luminescent quantum yield for Tb4(L3)4 (Φ = 82%) being obtained. In contrast, ligands with amido-pyridine-triazole (APT) or TPA chelates show much weaker sensitization ability. Energy levels for all ligands were measured, and TD-DFT calculations were employed to shed light on the sensitization mechanism. Finally, white-light emission systems formed by combining the desired luminescent compounds have been demonstrated. Our strongly luminescent LOPs provide new candidates for photochemical supramolecular devices.

Structural Diversity of Lanthanide 3-Nitrotrispyrazolylborates: Tunable Nuclearity and Intra-Ligand Charge Transfer Sensitization of Visible and NIR Ln3+ Emission

“…A modified Jablonski diagram (Figure ) was constructed to represent the various photophysical processes that lead to sensitized Ln 3+ emission in the title n -Ln complexes, utilizing the information from the energy and identity of the S n and T n states of 3-NO 2 Tp – . This represents, to the best of the authors’ knowledge, the first example of triplet intraligand charge transfer sensitization ( 3 ILCT) , of Ln 3+ emission, where ILCT sensitization is usually characterized as being singlet in nature ( 1 ILCT). − …”

Eu(III)–DO3A and BODIPY dyad as a chemosensor for anthrax biomarker

“…Therefore, luminescent lanthanide complexes have displayed significant potential in various applications like biomedical analyses, [ 22,23 ] imaging agents, [ 24–26 ] sensors, [ 27 ] lighting and device applications. [ 28 ]…”

Isocyanate Insertion into a La–P Phosphide Bond: A Versatile Route to Phosphaureate-Bridged Heterobimetallic Lanthanide–Coinage-Metal Complexes

“…The chemistry of the lanthanides (Ln) has advanced to be a very important field of research in modern inorganic chemistry. 1 , 2 As lanthanides are well-known for their magnetic and luminescent properties, the applications of lanthanide-containing molecules range from molecular magnetism 3 − 11 and (bio)analytical sensors 12 − 14 to optical communication 15 and modern catalysis. 16 − 31 In recent years, new strategies to systematically analyze and design lanthanide complexes with the desired chemical, magnetic, or photophysical properties have emerged.…”

“…The chemistry of the lanthanides (Ln) has advanced to be a very important field of research in modern inorganic chemistry. , As lanthanides are well-known for their magnetic and luminescent properties, the applications of lanthanide-containing molecules range from molecular magnetism − and (bio)­analytical sensors − to optical communication and modern catalysis. − In recent years, new strategies to systematically analyze and design lanthanide complexes with the desired chemical, magnetic, or photophysical properties have emerged. ,,− In this context, transition metals such as iron­(0/II/III), − nickel­(II), − and zinc­(II) ,, have been used to influence the magnetic behavior of lanthanide compounds, whereas e.g. iridium­(III), rhenium­(I), platinum­(II), − palladium­(II), zinc­(II), , gold­(I), ,, and silver­(I) have been introduced for efficient sensitizing of lanthanide luminescence − in heterobimetallic or -trimetallic systems.…”