Luminescent studies of binuclear ternary europium(III) pyridineoxide tetrazolate complexes containing bis‐phosphine oxide as auxiliary co‐ligands

Abstract

A new class of antenna chromophores so called 'tetrazolates' have not been explored much for lanthanide luminescencent complexes. However, we have already published several articles considering pyridineoxide tetrazolates as sensitizer with lanthanide ions. Although this class of antenna attracted much less attention because of its poor photoluminescence quantum yields (tris-pyridineoxide tetrazolate europium complex = 13% in solution) we tried and successfully achieved to improve the photoluminescence quantum yields for this particular antenna molecule by replacing coordinated water from the inner coordination sphere of europium ion by introducing phosphine oxides as additional chromophore. In the present article the two bis-phosphine oxides attach two molecules of tris-pyridineoxide tetrazolate europium(III) complex which leads to the improvement of the overall molar absorption coefficients as well as photo-physical properties of the complexes. We found more than two-fold increase (31% in solution) in photoluminescence quantum yield with one of the coordinated phosphine oxides comparing with that of tris-pyridineoxide tetrazolate europium(III) complex.

Self-Assembly of Lanthanide-Based Metallogel Nanoplates into Microcubic Blocks as Self-Calibrating Luminescent Methanol Sensors

“…The sharp peak at 1724 cm –1 and the bands at 1400–920 cm –1 correspond to the ν (CO) and the δ (O–H) mode of the carboxyl groups in BTC, which moved to lower wavenumbers in the three xerogels . Moreover, the characteristic bands at 1634–1385, 1638–1384, and 1636–1395 cm –1 in the three xerogels correspond to the asymmetric and symmetric tensile vibration peaks of the coordinated COO – , respectively. , Therefore, the above FT-IR spectra changes clearly show the coordination of metal and ligand during the formation of metallogels. − In addition, most of the main vibration peaks shift to lower wavenumbers after gelation, indicating hydrogen bond formation. , …”

Self-Healable Lanthanoid-Based Metallogels: Dye Removal and Crystallization in the Confined Gel State

“…65 The IR band of the tetrazole moiety at 1642 cm −1 shifts toward the region of 1614−1604 cm −1 after the coordination of the tetrazole N atom to Ln 3+ during the metallogel formation. 66 Furthermore, the participation of the noncovalent interaction has been corroborated by the powder XRD spectra obtained for all the four metallogels (Figure S13). In the PXRD spectra, the peak at 2θ = 35.14°has a corresponding dspacing value of ∼2.55 Å for M1G6Cl, the peaks at 2θ = 35.04°have corresponding d-spacing values of 2.56 Å for M2G6Cl and M1G6NO 3 , and the peak at 2θ = 35.42°has a corresponding d-spacing value of 2.53 Å for M3G6NO 3 , indicating the participation of extensive hydrogen bonding, which plays a significant role during the supramolecular selfassembly process that leads to the formation of the metallogels.…”

“…The C–H stretching vibration (CH 2 of tetrazoles) at 3241 cm –1 for H 2 G6 characteristically shifts downfield to the region of 3213–3172 cm –1 after the formation of the metallogels, indicating hydrogen bond formation . The IR band of the tetrazole moiety at 1642 cm –1 shifts toward the region of 1614–1604 cm –1 after the coordination of the tetrazole N atom to Ln 3+ during the metallogel formation …”

Investigations into spectroscopic and optoelectronic behaviour of furoic acid‐based Eu(III) complexes for advanced photonic applications

“…The emergence of more intense emission due to the 5 D 0 ‐ 7 F 2 transition compared with that of 5 D 0 → 7 F 1 was a relevant feature for the complexes C1–C4, and conveyed the asymmetric surrounding of the metal ion that lacked the inversion symmetry. [ 31–33 ] In comparison with binary (C1) complexes, the ternary C2–C4 complexes showed a higher luminescence; this gave a specific indication regarding the synergistic effects of the ancillary ligands that sensitized the trivalent europium ion. When these N‐containing ancillary ligands replaced the coordinated water molecules, there was a reduction in nonradiative energy losses that was a consequence of the quenching phenomenon, and therefore led to an enhancement of PL intensity.…”