Antiaromaticity, as introduced in 1965, usually refers to monocyclic systems with 4n π electrons. This concept was extended to all-metal molecules after the observation of Li₃Al₄⁻ in the gas phase. However, the solid-phase counterparts have not been documented to date. Herein, we describe a series of all-metal antiaromatic anions, [Ln(η⁴-Sb₄)₃]³⁻(Ln=La, Y, Ho, Er, Lu), which were isolated as the K([2.2.2]crypt) salts and identified by single-crystal X-ray diffraction. Based on the results obtained from the chemical bonding analysis, multicenter indices, and the electron-counting rule, we conclude that the core [Ln(η⁴-Sb₄)₃]³⁻ fragment of the crystal has three locally π-antiaromatic Sb₄ fragments. This complex represents the first locally π-antiaromatic all-metal system in the solid state, which is stabilized by interactions of the three π-antiaromatic units with the central metal atom.

Antiaromaticity, as introduced in 1965, usually refers to monocyclic systems with 4n π electrons. This concept was extended to all-metal molecules after the observation of Li₃Al₄⁻ in the gas phase. However, the solid-phase counterparts have not been documented to date. Herein, we describe a series of all-metal antiaromatic anions, [Ln(η⁴-Sb₄)₃]³⁻(Ln=La, Y, Ho, Er, Lu), which were isolated as the K([2.2.2]crypt) salts and identified by single-crystal X-ray diffraction. Based on the results obtained from the chemical bonding analysis, multicenter indices, and the electron-counting rule, we conclude that the core [Ln(η⁴-Sb₄)₃]³⁻ fragment of the crystal has three locally π-antiaromatic Sb₄ fragments. This complex represents the first locally π-antiaromatic all-metal system in the solid state, which is stabilized by interactions of the three π-antiaromatic units with the central metal atom.

A series of highly luminescent-active metal–organic frameworks (MOFs) 1–3 with hierarchical pores have been rationally constructed and fully characterized. The predesigned semi-rigid hexacarboxylate ligand hexa[4-(carboxyphenyl)oxamethyl]-3-oxapentane acid (H₆L) has been adapted with various space-directed N donors (i.e., 2,2’-bipyridine, 4,4′-di(1H-imidazol-1-yl)-1,1′-biphenyl, and 1,3,5-tri(1H-imidazol-1-yl)benzene) from a bidentate V-shape to a tridentate Y-shape. This family of multifunctional MOF materials represents a variety of potential applications in the following aspects: first, as luminescent sensors that show a fast and sensitive detection for pollutant CrO₄²⁻ and Cr₂O₇²⁻ ions in aqueous media; second, as adsorbents that can rapidly remove harmful organic dyes; third, as an antenna that can effectively sensitize visible-light-emitting Tb³⁺ ions. These multifunctional MOF materials combine optical-sensing, adsorption, and sensitization properties, thus are very useful in many potential applications. Furthermore, these materials have proved to be reusable.

Reaction of uranyl dications with (2-carboxyethyl)(phenyl)phosphinic acid (CPPA, H₂L) under hydrothermal conditions gave two layered isomers (UO₂)₂(L)₂, namely, CPP-U1 and CPP-U2. Both of them feature edge-sharing uranyl dimers as structure-building units, which are ligated by CPP ligands in different ways, thus leading different layered arrangements. With the addition of imidazole derivatives, two three-dimensional structures UO₂(L)(dib)_0.5 (CPP-U3) and UO₂(L)(bbi)_0.5 (CPP-U4) were generated, in which the similar uranyl-phosphinate layers are connected by two different imidazole derivatives by means of the U–N connection [dib = 1,4-di(1H-imidazol-1-yl)benzene; bbi = 1,1′-(1,4-butanediyl)bis(imidazole)]. The syntheses, structure, as well as the IR spectra, and luminescent and photocatalytic properties of these uranyl organophosphinates are reported in this paper.

The luminescent properties of a family of lanthanide metal–organic frameworks LnL (Ln=Y, La–Yb, except Pm; L=4,4′-({2-[(4-carboxyphenoxy)methyl]-2-methylpropane-1,3-diyl}bis{oxy})dibenzoic acid) have been explored, and the energy-transfer process in the compounds has been carefully analyzed. The visible-emitting Tb_0.08Gd_0.92L and the near-infrared (NIR)-luminescent Yb_0.10Gd_0.90L show excellent optical performances and can be considered as fluorescent probes for acetone sensing based on luminescence quenching effects arising from host–guest interactions. Moreover, GdL exhibits a strong second harmonic generation (SHG) signal 6.1 times that of potassium dihydrogen phosphate (KDP) and an outstanding phase-matchable effect. These lanthanide compounds combining fluorescent and nonlinear optical (NLO) properties could meet further requirements as multifunctional materials.