Reaction of alkylamine surfactants with carbon dioxide: relevance to nanocrystal synthesis.

Exposure of tetradecylamine, hexadecylamine, and octadecylamine to CO(2) results in their transformation to alkylammonium alkylcarbamate (AAAC) pairs, which we find is a major source of irreproducibility in nanoparticle synthesis. Controlled exposure to CO(2) allows for highly uniform, ultranarrow ZnS nanorods coated with tetradecylamine to be reproducibly obtained in a single step. The crystal structures of the alkylamines and their AAAC analogs were investigated by powder X-ray diffraction and their isostructural three-dimensional unit cells are reported.