CHARGE-TRANSFER INTERACTIONS IN SOME POLY[[ORTHO-(TRIMETHYLSILYL)PHENYL]ACETYLENE] ACCEPTOR COMPLEXES

Charge transfer (CT) interactions between poly[[o-(trimethylsilyl)phenyl]acetylene] or poly(o-Me3SiPA) and some electron acceptors were studied by ultraviolet-visible and infrared absorption spectroscopy and by x-ray photoelectron spectroscopy (XPS). The electron acceptors used included iodine, bromine, o-chloranil, o-bromanil, 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), and tetracyanoethylene (TCNE). Varying degrees of CT interactions were observed in all of the polymer/acceptor complexes studied. The electrical conductivities-sigma of the organic acceptor complexes exhibited a strong acceptor concentration dependence at low acceptor levels, with the DDQ complex exhibiting the highest-sigma. The extent of CT and the redistribution of charges resulting from the CT in all the complexes were revealed by XPS. The poly(o-Me3SiPA)/I2 complex film lost iodine spontaneously while more than half of the bromine in the poly(o-Me3SiPA)/Br2 complex existed as covalently bonded bromine, even at low halogen loading.