Matrix infrared spectroscopic and density functional theoretical investigations on thorium and uranium atom reactions with dimethyl ether

Abstract

Reactions of laser-ablated thorium and uranium atoms with dimethyl ether were investigated using matrix isolation infrared spectroscopy. Four types of reaction products for both uranium and thorium were identified using deuterium substituted samples as well as density functional frequency and energy calculations. Ground state uranium and thorium atoms react with dimethyl ether spontaneously to give the M(CH₃OCH₃) complexes (M = Th, U) on annealing, which are predicted to have C_2v symmetry with triplet (Th) and quintet (U) ground states. Subsequent visible irradiation produces the divalent CH₃OThCH₃ and CH₃OUCH₃ insertion products with singlet and quintet states lowest in energy. Further UV irradiation induces isomerization of the CH₃OMCH₃ molecules to the (CH₃)₂MO isomers with MO double bonds and pyramidal structures. In the presence of another dimethyl ether reagent, evidence for (CH₃O)₂M(CH₃)₂ molecules is also produced upon UV irradiation.