Copper(I) iodide (CuI)-based inorganic-organic hybrid materials in the general chemical formula of CuI(L) are well-known for their structural diversity and strong photoluminescence and are therefore considered promising candidates for a number of optical applications. In this work, we demonstrate a systematic, bottom-up precursor approach to developing a series of CuI(L) network structures built on CuI rhomboid dimers. These compounds combine strong luminescence due to the CuI inorganic modules and significantly enhanced thermal stability as a result of connecting individual building units into robust, extended networks. Examination of their optical properties reveals that these materials not only exhibit exceptionally high photoluminescence performance (with internal quantum yield up to 95%) but also that their emission energy and color are systematically tunable through modification of the organic component. Results from density functional theory calculations provide convincing correlations between these materials' crystal structures and chemical compositions and their optophysical properties. The advantages of cost-effective, solution-processable, easily scalable and fully controllable synthesis as well as high quantum efficiency with improved thermal stability, make this phosphor family a promising candidate for alternative, RE-free phosphors in general lighting and illumination. This solution-based precursor approach creates a new blueprint for the rational design and controlled synthesis of inorganic-organic hybrid materials.

The self-assembly of cationic tetranuclear-metal building blocks generated in situ based on p-tertbutylthiacalix[4]arene and linear anionic ligands (1,4-benzenedicarboxylic acid) gave rise to an anionic truncated octahedral coordination cage through a [6 + 12] condensation. This research provides a new building block with unique geometry to construct coordination cages with multifunctional properties.

A series of cationic lanthanide-based metal–organic frameworks (MOFs), {[Ln3(bcbp)3(NO3)7]·NO3·ClO4} n (Ln = Tb (1), Gd (2), Eu (3); H2bcbpCl2 = 1,1′-bis­(4-carboxyphenyl)­(4,4′-bipyridinium) dichloride), have been synthesized under solvothermal conditions and structurally characterized. Single-crystal X-ray diffraction analyses reveal that compounds 1–3 are isostructural, in which Ln3-SBUs (SBUs = secondary building units) are connected with six adjacent Ln3-SBUs by six protonated bcbp ligands, leading to cationic lanthanide-based metal–organic frameworks. In addition, the counteranions (nitrate anions and perchlorate anions) reside in the frameworks via weak C–H···O hydrogen bonds. Furthermore, Eu-MOF displays strong red luminescence, which is further proven to be a highly selective and sensitive luminescent sensor toward Cr2O7 2– with a high quenching coefficient and low detection limit. Interestingly, Eu-MOF is also sensitive to ammonia and exhibits a rapid color change from yellow to blue-gray that can be distinguished by the naked eye when it is exposed to ammonia vapor. The UV–vis, IR, Raman, and EPR data reveal that the color change can be ascribed to an electron-transfer process and the radical generation caused by the nucleophilic attack of ammonia molecules.