Photoluminescence and Molecular Structure of Tetrakis(N, N-dimethyldithiocarbamato)europate(III)
Photoexcitation of the sulfur(S)-to-europium(Eu) charge-transfer bands in Na[Eu(S<SUB>2</SUB>CNMe<SUB>2</SUB>)<SUB>4</SUB>]·3.5H<SUB>2</SUB>O at the low temperature (< 100 K) leads to the <SUP>5</SUP>D<SUB>0</SUB>→<SUP>7</SUP>F<SUB>J</SUB> (J = 0–4) luminescence of Eu<SUP>3+</SUP> as a result of the energy transfer to the <SUP>5</SUP>D<SUB>0</SUB> state. The luminescence and excitation spectra reveal the dithiocarbamato-ligand phonon-assisted electronic transition involved in the small energy gap (∼1800 cm<SUP>−1</SUP>) between the <SUP>5</SUP>D<SUB>1</SUB> and <SUP>5</SUP>D<SUB>0</SUB> levels. The luminescence lifetime (0.11 ± 0.01 ms at 4.2 K) decreases with increasing temperature, probably due to the thermal crossover relaxation from <SUP>5</SUP>D<SUB>0</SUB> to the S→Eu charge transfer states.
- Chemistry letters
Chemistry letters 1997(9), 907-908, 1997-09
The Chemical Society of Japan