Ligand exchanges of L-type amine-ligated wurtzite CdSe nanoplatelets (NPLs) are investigated under two-phase conditions employing hexane as the nonpolar phase and DMF as the polar phase. Exchange with Z-type CdX 2 (X = Cl, Br, and I) produces NPLs having the stoichiometries {CdSe[CdCl 2 ] 0.27 }, {CdSe[CdBr 2 ] 0.24 }, and {CdSe-[CdI 2 ] 0.26 } and results in the transfer of the NPLs from the top, nonpolar phase to the bottom, polar phase. Exchange with [NH 4 ]X (X = Cl, Br, and I) results in L-to L′-type ligand exchange to ammonia (NH 3 ) ligation. This exchange also results from the use of gaseous or aqueous ammonia. The CdX 2 -and NH 3 -ligated NPLs exhibit excellent dispersibility in DMF. The two-phase exchanges produce significantly different outcomes than comparable exchanges conducted under single-phase (toluene/methanol) conditions, showing that ligation stoichiometries, the identities of the ligands, and the dispersibilities of the ligand-exchanged NPLs are strongly influenced by the exchange conditions.

Two-phase ligand exchange of amine-ligated, wurtzite, [CdSe­(n-octylamine)0.43(oleylamine)0.07] nanoplatelets with ammonium salts (NH4Cl or [NH4]2[ZnCl4]) or the Lewis acids (ZnCl2 or CdCl2) in N-methylformamide/hexane afford NMF-ligated [CdSe­(NMF)0.18(n-octylamine)0.09] nanoplatelets. Subsequent ligand exchanges with the intermediate NMF-ligated nanoplatelets give halometallate-ligated CdSe nanoplatelets having CdX3 – or ZnX4 2– ligands (X = Cl, Br, and I). Two-phase ligand exchange of [CdSe­(n-octylamine)0.43(oleylamine)0.07] nanoplatelets with ammonium salts [NH4]­[CdX3] in N,N-dimethylformamide afford halometallate ligation directly. Analysis of the absorption spectra and X-ray diffraction data of the halometallate-ligated nanoplatelets establish that the halometallates bind as intact, Z-type ligands.