A series of new mixed-ligand lanthanide trifluoroacetates of formula Ln­(4-cpno)­(tfa)3(H2O)·H2O (Ln = Sm, Eu, Gd, Tb, Dy; 4-cpno = 4-cyanopyridine N-oxide; tfa = trifluoroacetate) is reported. Trifluoroacetates were synthesized as chemically pure polycrystalline solids and their crystal structures were probed using single-crystal and powder X-ray diffraction. Ln­(4-cpno)­(tfa)3(H2O)·H2O solids make up an isostructural series in which LnO8 polyhedra are bridged by 4-cpno to form edge-sharing dimers. Trifluoroacetato connects these dimers to yield chains whose three-dimensional packing is governed by hydrogen bonds established between 4-cpno, trifluoroacetato, and water. 4-cpno serves as an efficient sensitizer of lanthanide-centered luminescence. UV excitation of its singlet manifold and subsequent energy transfer to the 4f levels of the lanthanides yield orange (Sm), red (Eu), green (Tb), and yellow (Dy) emissions. Sensitization efficiencies reach 81 and 64% for Eu and Tb hybrids, respectively. Tb­(4-cpno)­(tfa)3(H2O)·H2O displays a quantum yield of 52%, which coupled to the high absorptivity of 4-cpno, makes it a bright-green emitter under 292 nm excitation. Lanthanide trifluoroacetates may therefore serve as hybrid solid-state light emitters provided that adequate sensitizers are identified.

The reactivity of alkali–manganese(ii) and alkali trifluoroacetates towards amorphous SiO2 was studied in the solid-state with an eye towards the synthesis of alkali fluorosilicates.

Zinc borates are very important industrial materials with applications that include fire retardants and preservatives in wood. In this work, we report the preparation of three novel zinc borates: [Zn(NH)BO(OH)]·HO (ZB1), Zn(HBO)·2NH·4HO (ZB2), and [Zn(NH)][BO(OH)]·4HO (ZB3). The solid phases were characterized by elemental analysis, X-ray diffraction, infrared and Raman spectroscopy, scanning electron microscopy and thermal analysis. The crystal structures of ZB1 (monoclinic, Cc, a = 12.1972(8), b = 7.8314(5), c = 12.1441(8) Å and β = 107.404(5)°) and ZB3 (orthorhombic, Pbca, a = 15.0796(9), b = 11.8853(5) and c = 16.7606(8) Å) were determined. They are novel neutral Zn-polyborate complexes [Zn(NH)BO(OH)] hydrate and [Zn(NH)][BO(OH)] tetrahydrate salt, respectively. The complete assignment of infrared and Raman spectra was performed theoretically using DFT calculations. For ZB2 (obtained as a polycrystalline phase), powder X-ray diffraction confirmed a single phase and allowed the determination of the unit cell parameters and lattice type (rhombohedral, a = 36.78076 (6), c = 12.20052 (3) Å) with an expected formula Zn(HBO)·2NH·4HO suggesting that this compound is a complex triborate. Furthermore, a low-cost scalable synthetic procedure for ZB1 starting from zinc oxide and boric acid in ammonia solution with a high yield is also reported.