Bis(salicylato)borate as Versatile Sensitizer for Highly Luminescent Lanthanide Oxoborates from the Ultraviolet to Near Infrared with 4f and 5d Participation of the Lanthanides

Abstract

Several lanthanide bis(salicylato)borate (BSBs) compounds were synthesized from anhydrous lanthanide chlorides and pyridine (py). The reactions start with the formation of small complexes, as indicated by [ErCl 2 (py) 4 (BSB)], on to 1D polymers 1 ∞ [Ln(BSB) 3 (py) 2 ] (Ln = Y, La-Nd, Sm) with a reduced py content. As the lanthanide radii contract along the lanthanide (Ln) series, the formation of 2D networks of the constitution 2 ∞ [Ln(BSB) 3 (py)] (Ln = Sm, Eu, Tb, Dy, Er) is observed with the further release of py. The coordination polymers exhibit intense photoluminescence from the UV to the near-infrared (NIR) re- [a] 1355 ∞ [Pr(BSB) 3 (py) 2 ], [15] for which several isotypic examples were obtained, and 2 ∞ [Tb(BSB) 3 (py)] (9) nicely illustrate the product formation and impact of the decreasing pyridine content in

Statistic Replacement of Lanthanide Ions in Bis‐salicylatoborate Coordination Polymers for the Deliberate Control of the Luminescence Chromaticity

“…For Tb 3+ , transitions 5 D 4 → 7 F J , J=6–3, can be identified, and for Eu 3+ , transitions 5 D 0 → 7 F J , J=0–4, are observed [15,22] . Remarkably, and in contrast to 2 ∞ [Eu(BSB) 3 (py)], [16b] the most intense transition of Eu 3+ is 5 D 0 → 7 F 4 (λ max= 698 nm) and not 5 D 0 → 7 F 2 (λ em = 615 nm). As the components of both CPs are identical, the chemical and binding interaction, polarizability and covalence are supposed also to be quite similar.…”

“…This includes the yellow region, known as the yellow gap of primary LED phosphors [23] . Figure 6 displays a chromaticity diagram according to CIE [24] that identifies the colour coordinates of the mixed CPs and of the border phases 2 ∞ [Ln(BSB) 3 (py)], Ln=Eu, Tb [16b] …”

“…Thus, the [BSB] − is among the ligands that allow an efficient transfer of energy from the respective ligand onto the lanthanide ions, which is vital for a successful sensitization of the otherwise low light uptake of trivalent lanthanide ions due to the parity forbidden character of the 4 f‐transitions [15] . Together with the [BSB] − anion, one‐ and two‐dimensional coordination polymers and networks of the constituents were reported, recently: 1 ∞ [Ln(BSB) 3 (py) 2 ] (Ln=Y, La−Nd, Sm) [16] and 2 ∞ [Ln(BSB) 3 (py)] (Ln=Sm, Eu, Tb, Dy, Er) [16b] …”

S-Heptazine N-ligand based luminescent coordination materials: synthesis, structural and luminescent studies of lanthanide–cyamelurate networks

“…For Dy-Cy, the emission lifetime is 3.48 μs at 298 K, which is in the usual range for Dy 3+ -containing coordination polymers (2.7 to 25.9 ms). [92][93][94] For Er 3+ coordination polymers, three regions are expected to show emission signals: visible (350-700 nm), near-IR (900-1400 nm), and above 1400 nm. [95][96][97] The emission of Er-Cy in the 350-700 nm region is readily observed (Fig.…”