Metallosiloxanes with Acetylacetonate Ligands

Abstract

The reactions of neutral cage metallophenylsiloxanes [PhSiO2]6M6[PhSiO2]6 (M = Cu or Ni) of the sandwich type with alkaline acetylacetonate K(Acac) and of alkaline cage metallosiloxane [PhSiO2]12Cu4Na4 of the globular type with the neutral complex Co(Acac)2 are studied. Hexanuclear Cu6- (I) and Ni6-phenylsiloxanes (II) and octanuclear (Cu4,Co4)-phenylsiloxane (III) formed in the reactions are studied by X-ray diffraction analysis (CIF files CCDC nos. 1974285 (I), 1974286 (II), and 1974287 (III)). It is shown that the type of the structure (sandwich or globular) of the initial metallosiloxane is retained in all cases. However, in the case of Ni-siloxane, the coordination with two Acac ligands results in an appreciable shift of the siloxane cycles relative to each other and in the transformation of the usual sandwich characteristic of neutral Ni-phenylsiloxane into a distorted sandwich. The presence of four Acac ligands in globular (Cu4,Co4)-phenylsiloxane lead to the elongation of the distance between two linear Cu–Cu fragments of the molecules, which provides the formation of the structure of the “biconvex lens” type.