Carborane-containing stereoregular cyclic phenylsiloxanes: synthesis, structure and properties

The synthesis of novel stereoregular carborane-containing phenylcyclosiloxanes (4, 5, 6, 8, and 12 -SiO- units in the ring) has been developed. The structures of all compounds were confirmed by a series of physicochemical methods. Tris-cis-tris-trans-dodeca[phenyl(1(3-(9-m-carboranyl)propyl)dimethylsiloxy)]cyclododecasiloxane has been studied by NMR spectroscopy and it was found that such a configuration of the ring makes two methyl groups diastereotopic, resulting in magnetic non-equivalence of the protons of these groups. The results of thermal studies of the obtained compounds are also described. The synthesis of novel stereoregular carborane-containing phenylcyclosiloxanes (4, 5, 6, 8, and 12 -SiO- units in the ring) has been developed.