Highly NIR-emitting ytterbium complexes containing 2-(tosylaminobenzylidene)-N-benzoylhydrazone anions: structure in solution and use for bioimaging

Solution behaviour in DMSO using 1D and 2D NMR spectroscopy was performed for lanthanide complexes Ln(L)(HL) and Ln(HL)2Cl, containing non-macrocyclic 2-(tosylamino)-benzylidene-N-benzoylhydrazone (H2L), and the structure of [Yb(L)]+ cation in...

Ytterbium complex with 2-(tosylamino)-benzylidene-N-(2-halobenzoyl)-hydrazones for solution-processable NIR OLEDs

A series of ytterbium complexes with halogenated 2-(tosylamino)-benzylidene-N-(2-benzoyl)-hydrazones was obtained for NIR OLED applications. Halogenation resulted in a significant solubility increase, while photophysical and electronic properties of the obtained complexes...

PECULIARITIES OF STRUCTURE AND SPECTRAL-LUMINESCENT PROPERTIES OF CARBOXYMETHOXY-SUBSTITUTED CALIX[4]ARENES AND THEIR COMPLEXES WITH LANTHANIDES

Spectral-luminescent properties of a variety of carboxymethoxy-substituted p-tert-butyl-calix[4]arenes and their complexes with lanthanides (Nd, Er, Yb) that exhibit the 4f-luminescence in the IR-spectrum region have been investigated. The effect of substitution of hydrogen phenolic atoms by carboxymethoxy groups on the stability and spectral-luminescent characteristics of both the ligands and lanthanide complexes was analyzed. Thus, based on the combination of the results obtained by means of elemental analysis, mass spectrometry, IR and 1H NMR spectroscopy, and taking into account the data of pH-metric titration, spectrophotometric and luminescence measurements, it can be concluded that lanthanide ions form neutral complexes of 1:1 ratio with L1H4 - L4H4. This is explained by the presence of mobile hydrogen atoms of phenol and/or carboxyl groups in the molecules of these ligands. An increase in the number of donor substituents leads to changes in the number of solvent molecules in the series L3H4 < L1H4 < L2H4 < L4H4 from 0.8 to 2.4 for neodymium complexes, from 1.2 to 2.2 - for ytterbium complexes. Both the quantum yield and lifetime of the 4f-luminescence of the neodymium and ytterbium complexes and also the luminescence intensity of the erbium-containing compounds change in the same order.

Redox-Modulations of Photophysical and Single-molecule Magnet Properties in Ytterbium Complexes Involving Extended-TTF Triads

The reaction between the 2,2’-benzene-1,4-diylbis(6-hydroxy-4,7-di-tert-butyl-1,3-benzodithiol-2-ylium-5-olate triad (H2SQ) and the metallo-precursor [Yb(hfac)3]⋅2H2O led to the formation of a dinuclear coordination complex of formula [Yb2(hfac)6(H2SQ)]⋅0.5CH2Cl2 (H2SQ-Yb). After chemical oxidation of H2SQ in 2,2’-cyclohexa-2,5-diene-1,4-diylidenebis(4,7-di-tert-butyl-1,3-benzodithiole-5,6-dione (Q), the latter triad reacted with the [Yb(hfac)3]⋅2H2O precursor to give the dinuclear complex of formula [Yb2(hfac)6(Q)] (Q-Yb). Both dinuclear compounds have been characterized by X-ray diffraction, DFT optimized structure and electronic absorption spectra. They behaved as field-induced Single-Molecule Magnets (SMMs) nevertheless the chemical oxidation of the semiquinone to quinone moieties accelerated by a factor of five the relaxation time of the magnetization of Q-Yb compared to the one for H2SQ-Yb. The H2SQ triad efficiently sensitized the YbIII luminescence while the chemical oxidation of H2SQ into Q induced strong modification of the absorption properties and thus a quenching of the YbIII luminescence for Q-Yb. In other words, both magnetic modulation and luminescence quenching are reached by the oxidation of the protonated semiquinone into quinone.

Understanding the near-infrared fluorescence and field-induced single-molecule-magnetic properties of dinuclear and one-dimensional-chain ytterbium complexes based on 2-hydroxy-3-methoxybenzoic acid

Two Yb(iii) complexes with a dinuclear and belt-like one-dimensional chain structure were reported. Their near-infrared luminescence and single-molecule magnetic properties were investigated in detail.

Europium and ytterbium complexes with o-iminoquinonato ligands: synthesis, structure, and magnetic behavior

Oxidation of Ln(ii) o-amidophenolates with o-iminoquinone leads to ligand mixed-valent o-iminosemiquinonato-o-amidophenolato complexes of Ln(iii).