The unusual UV absorption behavior of chloro functionalized oligosilane dendrimers

The unusual UV spectroscopic behavior of the chloro functionalized oligosilane dendrimers [R(Me3Si)2Si–Me2Si]3Si–Cl (3a,b) derived from reactions of R(Me3Si)2Si–K (2a,b) with Cl–Si(SiMe2Cl)3 (1) is reported (a; R = SiMe3 and b; R = Me). The dendritic silanol [Me(Me3Si)2Si][Me(Me3Si)2Si–Me2Si]2Si–SiMe2OH (6) has been isolated as a side product and was characterized by X-ray structure analysis.

The functionalized oligosilane dendrimers of formula [Me(Me3Si)2Si][Me(Me3Si)2Si–Me2Si]2Si–SiMe2OH and [R(Me3Si)2Si–Me2Si]3Si–Cl (R = SiMe3, Me) have been synthesized and structurally characterized. The absorption maximum of the latter compounds was found to be significantly red shifted in comparison to their permethylated analogues.Figure optionsDownload as PowerPoint slide