TY - JOUR
T1 - Thermally Activated Photophysical Processes of Organolanthanide Complexes in Solution
AU - Thor, Waygen
AU - Kai, Hei Yui
AU - Zhang, Yonghong
AU - Wong, Ka-Leung
AU - Tanner, Peter A.
N1 - Funding Information:
K.-L.W. thanks the financial assistance from the Hong Kong Research Grants Council Grant No. 12300021. The Dr. Mok Man Hung Endowed Professorship in Chemistry, HKBU-Durham Lanthanide Joint Research Center – Lanthanide Tools for Systems Medicine (SDF19-1011-P02) and the Centre for Medical Engineering of Molecular and Biological Probes (AoE/M-401/20) are also gratefully acknowledged (K.-L.W.).
Publisher Copyright:
©
PY - 2022/6/2
Y1 - 2022/6/2
N2 - The effect of temperature upon the lanthanide luminescence lifetime and intensity has been investigated in toluene solution for the complexes LnPhen(TTA)3 (Ln = Eu, Sm, Nd, Yb; Phen = 1,10-phenanthroline; TTA = thenoyltrifluoroacetonate). Thermally excited back-transfer to a charge transfer state was found to occur for Ln = Eu and can be explained by lifetime and intensity back-transfer models. The emission intensity and lifetime were also quenched with increasing temperature for Ln = Sm, and the activation energy for nonradiative decay is similar to that for the thermal population of Sm3+ excited states. Unusual behavior for lifetime and intensity was found for both Ln = Nd, Yb. The usually assumed equivalence of τ/τ0 = I/I0 (where τ is lifetime and I is intensity) does not hold for these cases. We infer that for these lanthanide systems the intensity decreases with temperature in the stage prior to population of the luminescent state. The lifetime changes are discussed.
AB - The effect of temperature upon the lanthanide luminescence lifetime and intensity has been investigated in toluene solution for the complexes LnPhen(TTA)3 (Ln = Eu, Sm, Nd, Yb; Phen = 1,10-phenanthroline; TTA = thenoyltrifluoroacetonate). Thermally excited back-transfer to a charge transfer state was found to occur for Ln = Eu and can be explained by lifetime and intensity back-transfer models. The emission intensity and lifetime were also quenched with increasing temperature for Ln = Sm, and the activation energy for nonradiative decay is similar to that for the thermal population of Sm3+ excited states. Unusual behavior for lifetime and intensity was found for both Ln = Nd, Yb. The usually assumed equivalence of τ/τ0 = I/I0 (where τ is lifetime and I is intensity) does not hold for these cases. We infer that for these lanthanide systems the intensity decreases with temperature in the stage prior to population of the luminescent state. The lifetime changes are discussed.
UR - http://www.scopus.com/inward/record.url?scp=85131269674&partnerID=8YFLogxK
U2 - 10.1021/acs.jpclett.2c01350
DO - 10.1021/acs.jpclett.2c01350
M3 - Journal article
SN - 1948-7185
VL - 13
SP - 4800
EP - 4806
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 21
ER -