Photophysics of main-chain polychromophores prepared by acyclic diene metathesis polymerization

A series of bis(vinylthienyl)silane monomers were prepared by reaction of 2 equiv of (vinylthienyl)lithium or (vinylthienyl)magnesium bromide with different dichlorosilicon dialkyls. The monomers react with the Schrock initiator Mo(NAr)(CHCMe2Ph)(OCMe(CF3)(2))(2) (Ar = 2,6-diisopropylphenyl), via the acyclic diene metathesis polymerization (ADMET) mechanism, to give poly(silanyl-dithienylethene) derivatives in excellent yield. GPC data suggest that the resulting polymers have short repeat sequences. Interchromophore cooperativity is evident, as a low energy emission, for polymer structures that have smaller side groups. This phenomenon is similar to the chromophore cooperativity observed in polymers containing stilbene fragments along the backbone.