Self‐Assembly of Tunable Heterometallic Ln–Ru Coordination Polymers with Near‐Infrared Luminescence and Magnetocaloric Effect

Abstract

A series of heterometallic lanthanide (Ln)-Ru coordination polymers, denoted Gd-1, Yb-2, and Nd-3, were prepared by solvothermal reaction of a carboxylate derivative of [Ru(bpy) ] (Rubpy, bpy=2,2'-bipyridine), oxalic acid, and Ln(OAc) by using the metalloligand strategy. Single-crystal X-ray diffraction indicated that the resulting isostructural heterometallic complexes have 1D butterfly-shaped Ln-Ru-based coordination chains but show slight differences in the coordination environments of the Ln centers. The introduced Ru(bpy) metalloligands could act as good light-harvesting antennas to effectively sensitize near-infrared (NIR) luminescence by energy transfer from the triplet metal-to ligand charge transfer state of Rubpy units to Ln (Yb or Nd) under the excitation in the visible-light region. Additionally, dopant-concentration-dependent behavior of the Ru-based emission and sensitized NIR emission was demonstrated in Gd-1. Finally, the magnetocaloric effect of Gd-1 was studied. The preparation of such heterometallic coordination polymers offers a versatile platform to investigate dimensionally controlled properties.

Anionic Lanthanide Metal–Organic Frameworks: Selective Separation of Cationic Dyes, Solvatochromic Behavior, and Luminescent Sensing of Co(II) Ion

“…The characteristic emission bands of Eu 3+ in Eu-MOF are mainly derived from the energy harvesting of Eu 3+ when excited at 385 and 396 nm, while the energy absorption of TATAT 6– ligand is mainly used for ligand-based emission. ,, Gd-MOF displays a ligand-centered broad emission band with a peak at 462 nm (Figure d), , similar to the 465 nm emission peak of the free H 6 TATAT ligand (Figure S36). The absence of the characteristic 4f–4f emission of Gd 3+ may be due to the high energy level of Gd 3+ that hinders energy transfer from ligand. − The absolute quantum yields of Tb-MOF (upon excitation at 341 nm), Eu-MOF (upon excitation at 396 nm), Dy-MOF (upon excitation at 341 nm), and Gd-MOF (upon excitation at 370 nm) are 32.5%, 11.0%, 2.1%, and 7.1%, respectively.…”

Hypoxia-Triggered Nanoscale Metal–Organic Frameworks for Enhanced Anticancer Activity

“…Nanoscale metal–organic frameworks (NMOFs), consisting of metal ions or clusters with organic ligands in nanoscale regions, have been primarily adopted as a promising platform to introduce active PS molecules into the frameworks or pores of MOFs for applications in catalysis, , optical devices, − and biomedicine. − These PSs as a functional unit could partly participate in the formation of MOFs at a very high content, whereas this cannot be done with other nanoparticle material classes. , Among them, Zr–porphyrin-based NMOFs have continually attracted much attention for their ease of synthesis, excellent thermal and chemical stabilities, and distinctive photophysical property. , For biological applications, these nanoscale forms could not only maintain the confinement effect of MOFs to enlarge the intramolecular distance of porphyrin PSs and to prevent the self-quenching but also produce the synergistic effect with metallic nodes, such as the so-called heavy atom effect, to facilitate the intersystem crossing (ISC) and improve the PDT efficiency. , Besides, these nanosized carriers can also preferentially accumulate at the tumor area to increase the therapeutic concentration of PSs in tumor cells. − Great progress in porphyrin-based NMOFs has been achieved recently in combining photodynamic and radiation therapy or chemotherapy, − but the multifunctional NMOF platform associating PDT with hypoxia-activated chemotherapy is rarely reported, which may benefit the treatment and imaging of heterogeneity and diversity of tumors.…”

Stereochemically Dependent Synthesis of Two Cu(I) Cluster-Based Coordination Polymers with Thermochromic Luminescence

“…Luminescent coordination polymers (CPs) or metal–organic frameworks (MOFs) have received immense attention due to their diverse topological structures and potential applications in detection and sensing, bioimaging, displays, and optical devices. − One promising strategy for the preparation of such functional materials is based on the inorganic connecting nodes and organic linkers within the coordination polymer framework, since those nodes or linkers could be exploited as luminophores to generate interesting luminescence. − As one important subclass of aggregation-induced emission (AIE) molecules, tetraphenylethylene (TPE) based ligands with carboxyl or pyridyl sites have been designed and successfully introduced into coordination polymer frameworks, resulting in intriguing luminescent properties and other potential applications. − A new zirconium tetraphenylethylene based MOF with a deep blue fluorescent emission and high quantum yield (99.9 ± 0.5%) under Ar has been obtained recently . In addition, a rare earth (RE) free, three-dimensional coordination polymer has been synthesized, and this compound contains a blue-excitable yellow phosphor, which can be used as a promising material for phosphor conversion WLEDs .…”