The Use of Phosphirenes as Conjugating Spacers in Polythiophene Chains

A series of thienyl-substituted phosphirene P−W(CO)5
complexes were synthesized by reaction of the transient terminal
phosphinidene complex [Ph−P−W(CO)5] with the appropriate
thienyl-substituted alkynes. The X-ray structural study of these
complexes shows coplanar thiophene and phosphirene rings,
suggesting a good inter-ring conjugation. A combined 13C
NMR−NBO analysis indicates that the CC double bond of
the phosphirene ring is highly polarizable. UV spectra show a
red-shift of the absorption when converting the alkynes into the
phosphirenes. CV data are also given.