| Abstract
| - The synthesis, solid-state structure, and UV spectroscopic properties of the first-generation single-core oligosilane dendrimer MeSi[SiMe2Si(SiMe3)2Me]2[SiMe2Si(SiMe3)3] (5) and the tethered analogue(CH2)4[Si(SiMe3)2SiMe2]2Si[SiMe2Si(SiMe3)3]Me (4) are reported. UV spectroscopic measurements insolution and in the solid state (diffuse reflectance) show the absorption maximum of tetramethylene-tethered 4 to be shifted to wavelengths longer than those of 5, the dendrimers MeSi[SiMe2Si(SiMe3)3]3(6) and MeSi[SiMe2Si(SiMe3)2Me]3 (7), and even that of the linear heptasilane Si7Me16. This can beexplained by the results of the X-ray analysis of 4 and 5, which reveal for 4 the presence of an A−D−A−D conformer, which is optimal for σ-conjugation, whereas in 5 only D−D−O−D conformers havebeen found.
- The synthesis, structure, and UV spectroscopic properties of the first tetramethylene-tethered dendritic oligosilane have been reported. The observed red shift of the absorption maximum of the title compound relative to those of other structurally analogous dendrimers is explained by the results of X-ray analysis, which reveal the presence of an A−D−A−D conformer, being optimal for σ-conjugation.
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