Four new rare-earth nitronyl nitroxide radical complexes: Magnetic and luminescent properties

Luminescent Radicals

Organic radicals are attracting increasing interest as a new class of molecular emitters. They demonstrate electronic excitation and relaxation dynamics based on their doublet or higher multiplet spin states, which are different from those based on singlet-triplet manifolds of conventional closed-shell molecules. Recent studies have disclosed luminescence properties and excited state dynamics unique to radicals, such as highly efficient electron-photon conversion in OLEDs, NIR emission, magnetoluminescence, an absence of heavy atom effect, and spin-dependent and spin-selective dynamics. These are difficult or sometimes impossible to achieve with closed-shell luminophores. This review focuses on luminescent organic radicals as an emerging photofunctional molecular system, and introduces the material developments, fundamental properties including luminescence, and photofunctions. Materials covered in this review range from monoradicals, radical oligomers, and radical polymers to metal complexes with radical ligands demonstrating radical-involved emission. In addition to stable radicals, transiently formed radicals generated in situ by external stimuli are introduced. This review shows that luminescent organic radicals have great potential to expand the chemical and spin spaces of luminescent molecular materials and thus broaden their applicability to photofunctional systems.

Metal-Organic Frameworks Based on Group 3 and 4 Metals

Metal-organic frameworks (MOFs) based on group 3 and 4 metals are considered as the most promising MOFs for varying practical applications including water adsorption, carbon conversion, and biomedical applications. The relatively strong coordination bonds and versatile coordination modes within these MOFs endow the framework with high chemical stability, diverse structures and topologies, and interesting properties and functions. Herein, the significant progress made on this series of MOFs since 2018 is summarized and an update on the current status and future trends on the structural design of robust MOFs with high connectivity is provided. Cluster chemistry involving Y, lanthanides (Ln, from La to Lu), actinides (An, from Ac to Lr), Ti, and Zr is initially introduced. This is followed by a review of recently developed MOFs based on group 3 and 4 metals with their structures discussed based on the types of inorganic or organic building blocks. The novel properties and arising applications of these MOFs in catalysis, adsorption and separation, delivery, and sensing are highlighted. Overall, this review is expected to provide a timely summary on MOFs based on group 3 and 4 metals, which shall guide the future discovery and development of stable and functional MOFs for practical applications.

A Fluorescent Zn(II) Coordination Polymer: Sensitive Detection of Cr2O72- in Water and Prevention Activity On the Deep Vein Thrombosis in Orthopedic Nursing

A novel coordination polymer (CP) based on Zn(II) of [Zn(tptc)_0.5(bpy)(H₂O)]_n (1) was synthesized through utilizing the 2,2'-bipyridine (bpy) chelating N donors and p-terphenyl-2,2'',5'',5'''-tetracarboxylate acid (H₄tptc) as the co-ligands. The measurements of the fluorescence were implemented for the complex 1 in solution and solid state, and the result reveals that 1 has a strong fluorescence and it is a sensory material with great development space to determine the trace Cr₂O₇^2- (with the detection limit of 36 ppb) in the water solutions via applying the fluorescence quenching effect. As the common disease in the orthopedic nursing, the deep vein thrombosis was the objective in this research. The weigh and length of the thrombus in the animals were measured and analyzed. In addition to this, the inflammatory response in the deep vein thrombosis animal was evaluated by RT-PCR. Molecular docking results indicate that only the carboxyl group could provide polar oxygen atoms for the formed hydrogen bonds to the protein.

Efficient detection of Cr3+ and Cr2O72− using a Zn(ii) luminescent metal–organic framework

We constructed a new luminescent metal–organic framework, [Zn₂(TCBPDC)_0.5(H₂O)₂]_n·G (G = guest molecules), and realized an efficiently luminescent sensing for Cr³⁺ and Cr₂O₇²⁻.

Magnetic and Optical Properties of Novel Lanthanide(III) Complexes Based on Schiff Base and β-Diketonate Ligands

A series of lanthanide-based self-assembling complexes constructed from Schiff base and β-diketonate ligands have been synthesised by the same method. They are one dimensional complexes ({[Ln(H2L)(tta)2(OAc)]·0.5H2O}n (Ln = Eu (1), Gd (2), Dy (3), Yb (4)); H2L = N,N′-bis(salicylidene)butane-1,4-diamine, tta = 2-thenoyltrifluoroacetone). Complexes 1 and 4 exhibit characteristic metal-centred emission in the solid state. The lifetimes and quantum yields of luminescence were also determined. Magnetic analysis reveals that complex 3 exhibits field-induced single-molecule magnet (SMM) behaviour with an energy barrier of 24.07 K.