Résumé
2,5-Dialkynylthiophenes (RC&z.tbd6;C)
2
C
4
H
2
S (R = Ph, Me
3
Si or Bu
t
) treated successively with HBCl
2
and Et
3
SiH in CH
2
Cl
2
undergo hydroboration polymerization to give intensely-coloured polymers of general structure -[CH&z.dbd6;CR-BCl-CR&z.dbd6;CH-C
4
H
2
S]
n
- for which the
11
B NMR resonances occur
ca
. 50 ppm upfield of those for analogous monomers.