Tetranuclear yttrium and gadolinium 2-acetylcyclopentanoate clusters: Synthesis and their use as spin-coating precursors for metal oxide film formation for field-effect transistor fabrication

Ferrocenyl-based di- and trinuclear lanthanide complexes: solid state structures, (spectro)electrochemical and DFT studies

Dinuclear and trinuclear ferrocenylcarboxylato-bridged lanthanide complexes of type [Ln(μO:κ2OO'-O2CFc)(O2CFc)2(H2O)(dmf)]2·(dmf)2 (Ln = Sm (2), Eu (3), Gd (4), Tb (5); Fc = Fe(η5-C5H4)(η5-C5H5)), and novel [Bu4N][Ln3(μ-O2CFc)3(μO:κ2OO'-O2CFc)3(O2CFc)3(μ3-OH)]·[Bu4N]Cl (Ln = Gd (6), Tb (7)) were prepared by the reaction of [LnCl3·6H2O] (synthesis of 2-5) or LnCl3 (synthesis of 6, 7) with FcCO2H (1) in the ratio of 1 : 3. As evidenced by single crystal X-ray structure determination, in 2-5 the lanthanide ions are connected by symmetric FcCO2 units. In addition, two ferrocenylcarboxylato groups are μ-bridged to LnIII. Each LnIII ion is coordinated by nine oxygen donor atoms derived from one H2O, one dmf and three carboxylates. The latter are found in chelating κ2 and bridging μ,κ3 coordination modes. Complexes 6 and 7 assemble three LnIII cores around a central μ3-netting hydroxide and nine FcCO2 entities. A combination of κ2, μ,κ2 and μ,κ3 coordination modes results in an eight-fold coordination sphere for each metal, which is best described as bicapped trigonal prismatic. IR spectroscopy confirms the chelating and bridging motifs. Electrochemical studies of complexes 2-7via cyclic voltammetry (CV) and square-wave voltammetry (SWV) showed one redox event between E°' = 250 and 260 mV vs. FcH/FcH+ for 2-5 with all six FcCO2 redox events superimposed. Complexes 6 and 7 show a total of three events in the CV with the oxidations of the nine FcCO2 units occurring in close proximity. Deconvolution of individual redox events correlates well with the mononuclear complex [Bu4N][Gd(O2CFc)4]. UV-Vis/NIR spectroelectrochemical measurements of 7 did not reveal electron transfer between either Fc units, nor the coordinated lanthanides and resembled the absorption behavior of [Bu4N][Tb(O2CFc)4]. DFT (Density Functional Theory) calculations on the B3LYP def2-TZVP level of theory were carried out to assign the order of redox events in 6 showing that the spatial distance towards the most recent redox center, instead of the binding mode, is decisive.

Luminescent lanthanide metal-organic framework test strip for immediate detection of tetracycline antibiotics in water

Tetracycline antibiotics (TCs) are a kind of commonly used antibiotics for treating infections, however, the overuse of TCs has adversely affected human health and the ecosystem. Thus, detection of TCs in water is important but challenging. In this work, a luminescent lanthanide metal-organic framework (LnMOF) sensor (1) for immediate detection of oxytetracycline (OTC) and tetracycline (TC) is developed. The sensor has high acid-base and water stability. Investigation reveals that among the 27 species of antibiotics, anions and cations under investigation, 1 shows highly selective sensing towards OTC and TC, and the detection is not disturbed by the presence of other species. The limit of detection (LOD) for OTC and TC are ultra-sensitive value of 1.95 and 2.77 nM, respectively. Investigation reveals the sensing mechanism is due to the inner filter effect. Further studies reveal that the sensor can be used in real sample monitoring. More importantly, test strips based on 1 are manufactured. They are an easy-to-use, low-cost, highly selective and sensitive sensing device for detecting OTC and TC. The sensing can be distinguished immediately and easily by the naked eyes, making it an excellent candidate to monitor OTC and TC in real use.