Synthesis of norbornenes containing cationic mono- and di(Cyclopentadienyliron)arene complexes and their ring-opening metathesis polymerization.

A no. of classes of polynorbornenes contg. cationic iron moieties within their side chains were prepd. via ring-opening metathesis polymn. with a ruthenium-based catalyst. The iron-contg. polymers displayed excellent soly. in polar org. solvents. The wt.-av. mol. wts. of these polymeric materials were estd. to be in the range of 18,000-48,000. Thermogravimetric anal. of these polymers showed two distinct wt. losses. The first wt. loss was in the range of 204-260° and was due to the loss of the metallic moieties, whereas the second wt. loss was obsd. at 368-512° and was due to the degrdn. of the polymer backbone. Cyclic voltammetry studies of the iron-contg. polymers showed that the 18 e- cationic iron centers underwent a redn. to give the neutral 19 e- complexes at half-wave potential (E1/2) = -1.105 V. Photolysis of the metalated polymers led to the isolation of the norbornene polymers in very good yields. Differential scanning calorimetry studies showed a sharp increase in the glass transition temps. up to 91° when rigid arom. side chains were incorporated into the norbornene polymers. [on SciFinder(R)]