Hydrothermal synthesis was used to obtain four new crystalline lattices derived from the functionalization of the [V₁₂B₁₈O₆₀H₆]ⁿ⁻ cluster: Na₈(H₃O){[Ni(H₂O)₅][V₁₂B₁₈O₆₀H₆]}·12.5H₂O (1), Na₅ (H₃O)₄{[Ni (H₂O)₃(en)][V₁₂B₁₈O₆₀H₆]}·9H₂O (2), and Na₉(H₃O){Zn_0.5[V₁₂B₁₈O₆₀H₆]}·11H₂O (3), [Hen][H₂en]{[Zn(en)₂]₃ [V₁₂B₁₈O₆₀H₆]}·3H₂O (4). All four compounds crystallize in the space group C2/c. Compounds (1) (2) and (4) are 0D species, while for (3) there is some degree of covalent connectivity between the anionic units, due to the presence of Zn^II cations with partial occupation between them. On the basis of structural data and BVS calculations, these functionalized cluster species present mixed-valence ratios of 11V^IV/1V^V for (1), (2) and (3) and 9V^IV/3V^V for compound (4). Compounds (1), (2) and (3) present sodium and hydronium ions in the crystalline lattice, while protonated ethylenediamine is observed in compound (4). These cations balance the negative charge of the corresponding clusters and stabilize the crystalline lattice by electrostatic interactions. In the studied compounds, Ni^II ions coordinate to the vanadyl oxygen atoms, whereas the Zn^II cations coordinate both to the vanadyl oxygen atoms and to the oxygen atoms bonded to boron centres. The electronic spectra in the low energy range are dominated by the IVCT phenomenon, since the functionalization of the cluster [V₁₂B₁₈O₆₀H₆]ⁿ⁻ by different transition metal ions does not affect the observed absorption bands.

In the present work, the synthesis and structural characterization of four new polyoxovanadoborate (BVO) frameworks based on the [V₁₂B₁₈O₆₀H₆]¹⁰⁻ polyanion are reported: (NH₄)₈(1,3-diapH₂)[V₁₂B₁₈O₆₀H₆]·5H₂O (1), K₈(NH₄)₂[V₁₂B₁₈O₆₀H₆]·18H₂O (2), K₁₀[V₁₂B₁₈O₆₀H₆]·10H₂O (3) and K₈Cs₂[V₁₂B₁₈O₆₀H₆]·10H₂O (4). A global antiferromagnetic behaviour is observed for these 10V^IV/2V^V mixed valence clusters. The magnetic data of 1, 2 and 3, which present different countercation environments, show that 1 is more coupled than 2 and 3. DFT calculations show that the positive charges strongly influence the polarization mechanism of the spin density of the vanadyl groups and the extent of the magnetic orbitals, therefore corroborating the experimental observation of the quenching effect of the magnetic coupling between vanadium centres of 2 and 3.

A series of hybrid organo–inorganic mononuclear lanthanoid complexes, [n-NBu₄]₃[LnH(PW₁₁O₃₉)(phen)₂]·H₂O, denoted as LM⁴-1-Ln (Ln = Dy^III, Tb^III, Eu^III, Nd^III, Er^III, Ho^III and Gd^III), were synthesized via hydrothermal synthesis and were structurally characterized by X-ray diffraction. The optical properties of all complexes have been investigated in the solid state. The temperature-dependent emission spectra of LM⁴-1-Dy, LM⁴-1-Tb and LM⁴-1-Eu complexes show intense lanthanoid emissions in the visible region, while LM4-1-Nd shows near-infrared (NIR) luminescence. The Eu^III complex shows typical strong red emissions from the ⁵D₀ → ⁷F_0,1,2,3,4 transitions, with the CIE colour coordinates (0.631,0.364), the colour purity value of 83.9% and a quantum yield of up to 4.3%, suggesting that the organic fragment has an effect on the optical properties compared to fully inorganic systems, making this complex very attractive as a red component of light-emitting diodes. The luminescence decays of LM⁴-1-Dy, LM⁴-1-Tb and LM⁴-1-Eu exhibit a biexponential behaviour, with τ_AV = 4.1(7) μs, 0.35(2) ms and 0.94(3) ms, respectively. The values obtained for Judd–Ofelt intensity parameters Ω₂ and Ω₄ support the interaction between the Eu^III and the ligands. Furthermore, those with Er^III and Ho^III present weak emissions in the visible region. The T-dependent photoluminescence results show that the LM⁴-1-Dy, LM⁴-1-Tb and LM⁴-1-Nd complexes have good temperature sensitivity, demonstrating that the materials have the potential to be used as a sensing element for luminescent thermometers in different temperature ranges.