Molecular Gyroscope Having a Halogen-substituted p-Phenylene Rotator and Silaalkane Chain Stators

2,3-Halophenylene-bridged polysilaalkane macrocages 1b and 1c were synthesized as novel molecular gyroscopes. X-ray crystallographic data showed that the structures of the macrocages were deformed to avoid contact between the halogens and the silaalkane cage. The 2,3-dichlorophenylene derivative 1c shows restricted rotation of the phenylene in solution as observed by variable temperature H-1 NMR spectroscopy.