Electronic circular dichroism in the 4f-4f transitions of a series of cesium tetrakis (+)-3-heptafluorobutyrylcamphorate Ln(iii) complexes

摘要

For electronic circular dichroism in the 4f-4f transitions (4f-4f CD) of a series of nine tetrakis ((+)-3-heptafluorobutyrylcamphorato) Ln ~(III) complexes, Δ-SAPR-8-C _4(llll) Cs[Ln((+)-hfbc) _4]·H _2O (Cs-Ln = Cs-Pr, -Nd, -Sm, -Eu, -Dy, -Ho, -Er, -Tm, -Yb), the spectroscopic observables such as the dissymmetry factor g = Δε/ε values with the intensities (Δε) of the CD components and the molar absorption intensities (ε) in the 4f-4f transitions between the ~(2S+1)L _J levels are compared with each other to test the classification of the CD components in the relative order of the observables predicted in terms of the selection rule for 4f-4f transitions. The 4f-4f CD-based chiroptical spectra-structural relationship across the series of Δ-SAPR-8-C _4(llll) lanthanide(iii) complexes is proposed: the signs of the 4f-4f CD or CPL in the hypersensitive transitions are related to the absolute configuration; Ln complexes with a negative CD component have the Δ-configuration around Ln ~(III) and vice versa.