Organic Polymers with Various Functional Groups in the Mainchain

Chemical conversion of the organocobalt polymers (3) into functional polymers is attainable by the polymer reactions with appropriate reagents. Novel polymers having pyridone moieties in the mainchain (12) are produced from 3 by the reaction with isocyanates (scheme 8). This polymer reaction proceeds smoothly at 120°C, and the content to the 2-pyridone moieties reaches about 70% with respect to the starting cobaltacyclopentadiene units. In this case, the remaining 30% is not the starting cobaltacyclopentadiene unit but the r -cyclobutadienecobalt moieties as a result of the rearrangement reaction. 

Polymers containing pyridine moieties in the mainchain (13) are likewise obtainable by the reaction of the polymers (3) with nitriles (scheme 9). In this case, polymers containing pyridine moieties (about 80%) are produced with an increase of the molecular weight of the polymers. The increase of the molecular weight is most probably due to the pyridine formation of the nitriles with the acetylene moieties at the polymer end catalyzed by the eliminated ( n -cyclopentadienyl)cobalt(I). In fact, it is also possible to prepare pyridine-containing polymers directly from diynes and nitriles in the presence of catalytic amount of 4 (scheme 10). Within the examined combinations, this catalytic polymerization by the pyridine-ring-formation process is 

The efficiency of these polymer reactions is affected by the reagents and the reaction conditions, which ranged from 70 to 100%. In the cases of polymer reactions that do not proceed in a quantitative fashion, no distinct decrease of the molecular weight of the produced polymers were observed because the lower efficiency of the polymer reactions does not mean the scission of the mainchain of the polymers but the conversion into other structures such as the cyclobutadienecobalt imit. 

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