Lanthanide complexes with 2-(tosylamino)benzylidene-N-benzoylhydrazone, which exhibit high NIR emission†
New NIR emitting materials were found among the lanthanide complexes with 2-(tosylamino)benzylidene-N-benzoylhydrazone. Complexes of Nd3+, Er3+ and Yb3+, as well as Eu3+, Gd3+ and Lu3+, 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.