Chiral diamine catalyzed induction of helical chirality in polysilanes.

Controlling the conformation polysilane through proton-metal exchange reaction of polymethyltolylsilane with alkyllithium using catalytic amount of chiral amines as the chiral origin has been realized. The produced polymers whose chiral origins are (−)-sparteine, ( S , S )-3 or ( S )-2 adopt the P conformation, and whose chiral origins are ( R , R )-3 or ( R )-2 adopt the M conformation. Under the external stimuli of ( S , S )-3 and ( R , R )-3, or ( S )-2 and ( R )-2, the prepared polymers, PS-11 and PS-12 or PS-3 and PS-2 assumed to induced CD spectra were virtual mirror images of each other. These results indicate that the chiral amines can not only induce the helicity of polysilanes, but control the direction of the helix. [ABSTRACT FROM AUTHOR]