Mechanistic Study of the Synthesis of CdSe Nanocrystals: Release of Selenium

We outline a reaction pathway for the cleavage of the PSe bond in trialkylphosphine selenide during the synthesis of CdSe nanocrystals. The reaction between cadmium carboxylate and trimethylphosphine selenide in the presence of an alcohol produces alkoxytrimethylphosphonium (<b>2</b>). Control experiments and density functional theory calculations suggested that the cleavage of the PSe bond is initiated by nucleophilic attack of carboxylate on a Cd²⁺-activated phosphine selenide to produce an acyloxytrialkylphosphonium intermediate (<b>1</b>), which is converted to <b>2</b> in the presence of an alcohol