Electronic spectra of eight-co-ordinate complexes of some lanthanoids-(III) with OO′-diethyl dithiophosphate

Abstract

A series of OO′-diethyl dithiophosphates (ddtp) of the trivalent lanthanoids La, Ce, Pr, Nd, Sm, Eu, Tb, and Ho, general formula [NEt₄][Ln(ddtp)₄], have been prepared. The electronic spectra have been investigated for methyl cyanide solutions in the spectral range 7 000–45 000 cm^–1 and bands attributed to electronic transitions of f—f, charge-transfer, and f—d type. With the cerium(III) complex five bands in the spectral range 27 000–37 000 cm^–1 are attributed to the five 4f→5d transitions. With the samarium, europium, and ytterbium compounds, a number of electron-transfer transitions are found and the ligand molecular orbitals involved are discussed.