D. Schmidt et al., SYNTHESIS OF 1-PHOSPHINOPHOSPHOLES AND THEIR TUNGSTENPENTACARBONYL COMPLEXES, Journal of organometallic chemistry, 529(1-2), 1997, pp. 197-203
A series of 1-phosphinophospholes 4a-d (R = tert-butyl (a), iso-propyl
(b), ethyl (c), phenyl (d)) and their pentacarbonyltungsten complexes
5a-d are synthesized and characterized. The P-31 NMR patterns of both
the complexed and free 1-phosphinophospholes follow similar trends. T
he X-ray structure of 5a reveals an elongated P-P bond due to steric e
ncumbrance, while the geometry of the phosphole moiety is not affected
.