Determination of contributions of various molecular groups to nonradiative deactivation of electronic excitation energy in β-diketonate complexes of ytterbium(III)

Abstract

Quantum yields and lifetimes of 2 F 5/2→2 F 7/2 fluorescence are measured for double and heteroligand complexes of ytterbium with dibenzoylmethane and thenoyltrifluoroacetone, as well as their analogs with a deuterated central C-H group dissolved in toluene and deuterated dimethyl sulfoxide (DMSO-d 0). Deuteration of β-diketone is shown to cause a significant increase in the lifetime of Yb3+ fluorescence (up to 72 μs for thenoyltrifluoroacetone in DMSO-d 6). Based on the experimental data, a system of equations is constructed that makes it possible to determine contributions of various molecular groups of a complex and the externalsphere solvent to nonradiative deactivation of the 2 F 5/2 state of ytterbium. Possible ways of producing Yb3+ complexes with improved fluorescent characteristics are discussed.