Lanthanide complexes with 2-(tosylamino)benzylidene-N-benzoylhydrazone, which exhibit high NIR emission

Abstract

New NIR emitting materials were found among the lanthanide complexes with 2-(tosylamino)benzylidene-N-benzoylhydrazone. Complexes of Nd(3+), Er(3+) and Yb(3+), as well as Eu(3+), Gd(3+) and Lu(3+), were synthesized for the first time. Owing to the absence of vibration quenching the ytterbium complex was found to exhibit a photoluminescence quantum yield of 1.4%. Since the sensitization efficiency was calculated to be 55%, the losses in the quantum yield are probably due to Yb-Yb resonant energy transfer.

On the Structural Features of Substituted Lanthanide Benzoates

“…For instance, unlike polymeric ytterbium 9‐anthracenates, which quantum yield was possible to be ca. 1.5‐fold increased by avoiding concentration quenching, mononuclear ytterbium Schiff base complexes Yb(L)(HL),, as shown by our recent, yet not published results, do not undergo concentration quenching: lifetime values of Yb(L)(HL), Yb 0.5 Lu 0.5 (L)(HL), and Yb 0.1 Lu 0.9 (L)(HL) coincide.…”

Short Radiative Lifetime and Non‐Triplet Sensitization in Near‐Infrared‐Luminescent Yb(III) Complex with Tripodal Schiff Base

“…This is consistent with the observation of the luminescent spectral shape. The τ obs values of YbL are lower than those reported for Yb(III) complexes containing C−H bonds (typically below 50 μs) [2–7] . The rate of the nonradiative deactivation of the Ln(III) excited state is inversely proportional to the distance between the Ln(III) and the C−H bond [22] .…”

“…The τ obs values of YbL are lower than those reported for Yb(III) complexes containing CÀ H bonds (typically below 50 μs). [2][3][4][5][6][7] The rate of the nonradiative deactivation of the Ln(III) excited state is inversely proportional to the distance between the Ln(III) and the CÀ H bond. [22] According to the crystal structure of YbL, there are methylene and methine CÀ H bonds with short Yb•••H distances (3.4-4.4 Å).…”

“…Typically, of Yb(III) complexes are very low (<1 %) [2] . Although Yb(III) complexes with higher (>1 %) have been recently reported, [3–6,7c,d] to design an Yb(III) complex with a high , it is still important to optimize η and .…”

Contribution of Energy Transfer from the Singlet State to the Sensitization of Eu3+ and Tb3+ Luminescence by Sulfonylamidophosphates

“…The commonly observed sensitization process for luminescent Eu 3+ and Tb 3+ complexes involves a triplet pathway in which the transfer of the energy absorbed by the ligand to the Ln 3+ ion takes place from the ligand‐centered triplet excited state (T 1 ) . Among thousands of publications on lanthanide complexes, only a few have included evidence of a dominant singlet (S 1 ) pathway . Dominant singlet energy transfer has seldom been observed, in the sensitization of lanthanide ions, because intersystem crossing (S 1 →T 1 ) is usually very fast due to not only the rather small S 1 –T 1 energy difference (ca.…”