Isolation of Amine Derivatives of (ZnSe)34 and (CdTe)34. Spectroscopic Comparisons of the (II-VI)13 and (II-VI)34 Magic-Size Nanoclusters

The spectroscopically observed magic-size nanoclusters (ZnSe)(34) and (CdTe)(34) are isolated as amine derivatives. The nanoclusters [(ZnSe)(34)(n-octylamine)(29 +/- 6)(di-n-octylamine)(5 +/- 4)] and [(CdTe)(34)(n-octylamine)(4 +/- 3)(di-n-pentylamine)(13 +/- 3)] are fully characterized by combustion-based elemental analysis, UV-visible spectroscopy, IR spectroscopy, and mass spectrometry. Amine derivatives of both (ZnSe)(34) and (CdTe)(34) are observed to convert to the corresponding (ZnSe)(13) and (CdTe)(13) derivatives, indicating that the former are kinetic products and the latter thermodynamic products, under the conditions employed. This conversion process is significantly inhibited in the presence of secondary amines. The isolation of the two new nanocluster derivatives adds to a total of nine of 12 possible isolated derivatives in the (II-VI)(13) and (II-VI)(34) families (II = Zn, Cd; VI = S, Se, Te), allowing comparisons of their properties. The members of these two families exhibit extensive spectroscopic homologies. In both the (II-VI)(13) and (II-VI)(34) families, linear relationships are established between the lowest-energy nanocluster electronic transition and the band gap of the corresponding bulk semiconductor phase.