Three ytterbium(III) complexes with aromatic N‐donors: Synthesis, structure, photophysical properties and thermal stability

Abstract

Three new ytterbium complexes of the general formula [YbL 2 Cl 3 ] with expanded aromatic N-donor based ligands based on 1,10-phenanthroline (dipyrido-[3,2-f : 2',3'-h]-quinoxaline (DPQ), 2-methyldipyrido-[3,2-f : 2',3'-h]-quinoxaline (MeDPQ) and 1,10-phenanthroline (Phen)) were synthesized and characterized using different structural analysis, simultaneous thermal analysis, and photoluminescence, and UV-Vis-NIR spectroscopy. The compounds were obtained by the reaction of ytterbium(III) chloride hexahydrate and the corresponding aromatic N-donor through substitution of water from the coordination sphere with the organic ligand. Photoluminescence studies revealed Yb 3 + -based NIR emission of the corresponding compounds with following luminescence lifetimes [Yb(DPQ) 2 Cl 3 ] (1) -7.8(1) μs, [Yb(MeDPQ) 2 Cl 3 ] (2) -9.3(1) μs, [Yb(Phen) 2 Cl 3 ] (3) -8.7(1) μs. The resulting complexes are stable under atmospheric conditions, exhibit good thermal stability, and start to oxidize only at sufficiently high temperatures: (1) at 470 °C, (2) at 430 °C, and (3) at 395 °C.

Crystal Structures of DNA Intercalating Agents Dipyrido[3,2-f:2′,3′-h]quinoxaline (dpq), (Benzo[i]dipyrido[3,2-a:2′,3′c]phenazine (dppn), and [Ir(ppy)2(dppn)][PF6] (Where Hppy = 2-Phenylpyridine)

“…The dpq molecule is planar, as indicated by the following key dihedral angles about the central benzene ring: N1-C5-C6-N2 = −1.0 (4) • , C9-C10-C11-N4 = 2.4 (4) • , and C3-C4-C12-N3 = −0.9 (4) • . These are of similar magnitude to the dihedral angles in the unbound dpq ligands that are cocrystallized in the structure of the bis(dihydrogen bis(pyrazolyl)borate-N,N )-(pyrazino[2,3-f][1,10]phenanthroline-iron complex [22]. Planarity is also generally maintained among the numerous examples of dpq ligands that are coordinated to transition metals or lanthanide ions [20,[22][23][24][25].…”

Enhancing the Analysis of Eu3+ Photoluminescence in Coordination Compounds in the Solid State by Determining their Refractive Index

“…Photoluminescence properties of Ln 3 + are generally studied in inorganic [1][2][3] or coordination compounds. [4][5][6][7][8][9][10][11] Furthermore, these metal ions could be used as dopants [12][13][14][15][16] or embedded in polymeric films. [17][18][19][20][21] In suitable coordination compounds, the organic ligand acts as an "antenna" for the sensitisation of Ln 3 + luminescence, being beneficial due to the low light uptake of lanthanide ions employing intra-4 ftransitions.…”

“…Due to the characteristic 4 f–4 f luminescence of trivalent lanthanides, their compounds are widely investigated as phosphors. Photoluminescence properties of Ln 3+ are generally studied in inorganic [1–3] or coordination compounds [4–11] . Furthermore, these metal ions could be used as dopants [12–16] or embedded in polymeric films [17–21] .…”

Development of comprehensive approaches to characterizing CuII complexes: structures in solution and solid‐state, dynamic behavior, and bioactivity

“…The synthesis and crystal structure of MeDPQ have been described previously. [35] In the available literature, thermodynamic parameters of copper(II) complexes with aromatic N-donors and amino acids in solution were mainly obtained at 25 °C against various salts: NaClO 4 or NaCl, KNO 3 or KCl. [28,[36][37][38][39][40][41] However, only sodium and potassium chlorides are present in rather high concentrations in the intercellular and intracellular space, respectively; [42] therefore, another salt background is inapplicable.…”

“…Its homolog, 2‐methyldipyrido[3,2‐f:2′,3′‐h]quinoxaline (MeDPQ), can be used to overcome low solubility and precipitation at relatively high concentrations in aqueous solution. The synthesis and crystal structure of MeDPQ have been described previously [35] …”