Solution-phase routes to surface-derivatized cadmium phosphide nanoparticles

Preparations of surface-derivatized cadmium phosphide nanoparticles from (1) a metallo-organic and (2) a reversed-micelle route are described. Homoleptic phosphido complexes containing the bulky P(SiPh{dollar}sb3)sb2{dollar} ligand were selected as precursors for the metallo-organic route. The complexes M (P(SiPh{dollar}sb3)sb2rbrack sb2,{dollar} where M = Zn, Cd, Sn, and Hg, were prepared from LiP(SiPh{dollar}sb3)sb2{dollar} and M (N(SiMe{dollar}sb3)sb2rbrack sb2{dollar} in 50-90% yields as crystalline (except M = Sn), hydrocarbon-soluble solids. X-ray crystallography reveals that Cd(P(SiPh{dollar}sb3)sb2rbracksb2{dollar} is a solid-state monomer with Cd having a linear two-coordinate geometry. Crystal data for Cd(P(SiPh{dollar}sb3)sb2rbracksb2{dollar}: monoclinic, C2/c, a = 26.536 (5) A, b = 13.862 (2) A, c = 17.380 (3) A, {dollar}beta{dollar} = 110.90 (1){dollar}spcirc, V{dollar} = 5972 (2) A{dollar}sp3, T{dollar} = {dollar}-{dollar}100{dollar}spcirc{dollar}C, Z = 4. On the basis of structures and stabilities of their complexes, the bulky P(SiPh{dollar}sb3)sb2{dollar} ligand is shown to be a closer steric and electronic equivalent to the N(SiMe{dollar}sb3)sb2{dollar} ligand than is the exactly homologous P(SiMe{dollar}sb3)sb2{dollar} ligand.; A metallo-organic route to cadmium phosphide nanoparticles is described that is analogous to the sol-gel process. The nanoparticles are prepared from the methanolysis of the precursor Cd (P(SiPh{dollar}sb3)sb2rbrack sb2,{dollar} and are isolated as a pyridine-soluble solid. Solution-phase and solid-state {dollar}sp{lcub}31{rcub}{dollar}P NMR are discussed and are consistent with nanoparticles of cadmium phosphide. Transmission electron microscopy reveals approximately spherical particles having diameters mostly in the range of 30-40 A, but that vary between 20 and 70 A. The cadmium phosphide nanoparticles retain large amounts of -OMe and -SiPh{dollar}sb3{dollar} residues as surface substitutents, which are responsible and necessary for the solubility of the particles and for arresting particle growth in the nanometer regime.; A reversed-micelle (water in heptane) preparation of narrowly dispersed, surface-derivatized, THF- and pyridine-soluble cadmium phosphide nanoparticles is described. The growth of the cadmium phosphide nanoparticles is induced by addition of NaOH (aq.) to micellar solutions of Cd(ClO{dollar}sb4)sb2{dollar} and P(SiMe{dollar}sb3)sb3.{dollar} The nanoparticle mean size is controlled by NaOH titration, affording nanoparticles with diameters in the range of 15-30 A, and size distributions of {dollar}pm{dollar}2 A about the mean. The nanoparticles are precipitated from the micellar solutions by addition of arenethiols and characterized by UV-visible spectroscopy, transmission electron microscopy, atomic force microscopy, X-ray powder diffraction, and SS MAS {dollar}sp{lcub}31{rcub}{dollar}P NMR.