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A brand-new application of thorium-bearing clusters in the field of ionizing radiation detection is exemplified by two novel hexanuclear thorium clusters, Th-bppCOO-1 and Th-bppCOO-2, which incorporate carboxylate-functionalized 2,6-di(pyrazol-1-yl)pyridine ligands. Notably, Th-bppCOO-1 is composed of an unprecedented [Th6(OH)4O4(H2O)5]12+ secondary building unit, the Th6 core of which is decorated by five H2O molecules. Furthermore, selective photoluminescence quenching responses of Th-bppCOO-1 and Th-bppCOO-2 toward X-ray over UV radiation have been demonstrated for the first time.

Rational design and synthesis of new photochromic sensors have been active research areas of inquiry, particularly on how to predict and tailor their properties and functionalities. Herein, two thulium 2,2':6',2''-terpyridine-4'-carboxylate (TPC)-functionalized metal-organic hybrids, Tm(TPC)2(HCOO)(H2O) (TmTPC-1) and Tm(TPC)(HCOO)2 (TmTPC-2) with different photochromic response behaviors, have been successfully prepared, allowing for straightforward investigations of the structure-property correlation. Single-crystal X-ray diffraction and electron paramagnetic resonance analyses revealed that the incorporation of a unique dangling decorating TPC unit in TmTPC-1 offers a shorter and more accessible π-π interaction pathway between the adjacent TPC moieties than that in TmTPC-2. Such a structural feature leads to the production of radical species via a photoinduced intermolecular electron-transfer (IeMCT) process upon UV or X-ray irradiation, which ultimately endows TmTPC-1 with a rather unusual UV and X-ray dual photochromism. A linear relationship between the change of UV-vis absorbance intensity and X-ray dose was established, making TmTPC-1 a promising dosimeter for X-ray radiation with an extremely high energy threshold (30 kGy). To advance the development for real-world application, we have fabricated polyvinylidene fluoride (PVDF) membranes incorporating TmTPC-1 for functioning either as a UV imager or as an X-ray radiation indicator. Lastly, TmTPC-1 exhibits high thermal stability (up to 400 °C) and radioresistance (at least 900 kGy), and also excellent reversibility of photochromic transformation (at least 5 cycles).

Expanding the family of lanthanide terpyridine coordination polymers has yielded eighteen new complexes with two different phases, Ln(TPC)2(HCOO)(H2O) (Ln-1) and Ln(TPC)(HCOO)2 (Ln-2) (Ln = Sm–Lu, except Tm). Both structures are composed of lanthanide cations interconnected by 2,2′:6′,2′′-terpyridine-4′-carboxylate ligands to yield one-dimensional chain topologies. However, the incorporation of an additional crystallographically unique decorative TPC ligand into Ln-1 gives rises to a distinct phase. The encapsulation of both metal- and ligand-based phosphors within single coordination polymers leads to dual-emission of the afforded materials. Furthermore, judicious lanthanide doping in heterometallic Ln-1 and Ln-2 allows for fine-tuning the photoluminescent colours over a wide range of gamut. Such a combination showcases the capability to fine-tune the emission colours from deep green, to red, and to blue. In addition, direct white-light emission upon UV excitation can be achieved in the SmxGd1−x-1 system.

By first applying a thorium-organic framework (Th-SINAP-2) as a radiation attenuator and by incorporating a terpyridine derivative (Htpbz) as a photo-responsive guest, selective photochromism in response to X-rays was achieved in the host-guest assembly of Htpbz@Th-SINAP-2. Such a combination endows the afforded material with the lowest detection limit of X-ray dose among all photochromic sensors and a brand-new function of X-ray dosimetry for thorium containing materials.

Targeted synthesis, through a heteroleptic methodology, has resulted in three types of lanthanide (Ln) coordination polymers (CPs) with tailored dimensionality, tunable photoluminescent colors, and distinct luminescence quenching upon UV and X-ray irradiation. The homoleptic Ln(tpbz)(NO

Five coordination compounds assembled from the pyridyl based ligand, Ni(PBN)4(N3)2, 1; {[Co(PPT)2·(H2O)2]·2H2O}n, 2; [Cu(PPT)]n, 3; {[Zn2(PPT)3(OH)]·2H2O}n, 4, and [Cd(PPT)2]n, 5 (PPT ​= ​5-(3-pyridylphenyl)tetrazole and PBN ​= ​4-(3-pyridyl)benzonitrile) have been solvothermally synthesized and characterized by single-crystal X-ray diffraction, powder XRD, elemental analysis, IR spectroscopy, solid state fluorescence and TG analysis. The PPT ligand in the complexes is generated via the in situ [2 ​+ ​3] cycloaddition in the reaction of the cyano groups of the organonitrile and sodium azide. Single-crystal X-ray diffraction analyses reveal compound 1 is an oligomer of 6-coordinated Ni(II) compound where the 6 coordination sites are occupied by six nitrogen atoms from four distinct PBN ligands and two azide ions, respectively. Compound 2 exhibits a 1D chain structure where the 6-coordinated cobalt centers are double connected by two upside down μ2-PPT ligands. Both compound 3 and compound 4 present the 2D sheet structures constructed by μ2-tetrazole-linked copper(I) dimmer and μ2-hydroxy-connected zinc(II) dimmer, respectively, with both centers of 4-coordinated fashions. Compound 5 is a dense 3D framework with the PPT ligand of a μ3-bridging mode. Structural analyses indicate the structural varieties of the dimensionalities in these compounds result from the coordination diversity of the PPT ligands. In addition, compound 3 represents a rare example of copper(II) that is experienced the self-reduction process during the in situ [2 ​+ ​3] cycloaddition and exhibits a blue emission at room temperature. Thermal stability analyses indicate the compounds 4 and 5 are stable up to 300 ​°C and the temperature dependent PXRD reveal the residues of compounds 4 and 5 are ZnO and CdCO3, respectively.