Cadmium Bis(phenyldithiocarbamate) as a Nanocrystal Shell-Growth Precursor

Cadmium bis(phenyldithiocarbamate) [Cd(PTC)(2)] is prepared and structurally characterized. The compound crystallizes in the monoclinic space group P2(1)/n. A one-dimensional polymeric structure is adopted in the solid state, having bridging PTC ligands and 6-coordinate pseudo-octahedral Cd atoms. The compound is soluble in DMSO, THF, and DMF and insoluble in EtOH, MeOH, CHCl3, CH2Cl2, and toluene. {CdSe[n-octylamine](0.53)} quantum belts and Cd(PTC)(2) react to deposit epitaxial CdS shells on the nanocrystals. With an excess of Cd(PTC)(2), the resulting thick shells contain spiny CdS nodules grown in the Stranski-Krastanov mode. Stoichiometric control affords smooth, monolayer CdS shells. A base-catalyzed reaction pathway is elucidated for the conversion of Cd(PTC)(2) to CdS, which includes phenylisothiocyanate and aniline as intermediates, and 1,3-diphenylthiourea as a final product.