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Alternating copolymerization of cyclohexene oxide and carbon dioxide catalyzed by noncyclopentadienyl rare‐earth metal bis(alkyl) complexes

“…As expected, both the catalytic activities and the carbonate linkages of the resultant polymers from copolymerization by 1b, 2a, 2b, and 3 were (3); N(1)-Lu(1)-N(2) 77.92 (7), N(1)-Lu(1)-C(18) 119.52 (8), N(2)-Lu(1)-C(18) 103.43 (8), N(1)-Lu(1)-O(1) 86.42 (7), N(2)-Lu(1)-O(1) 162.53 (7), C(18)-Lu(1)-O(1) 90.94 (8), N(1)-Lu(1)-C (19) 126.97 (8) enhanced to some extent when compared with those using toluene as solvent, in agreement with previous report (entries [16][17][18][19][20]. 15 On the basis of these results, we postulated that 1,4-dioxane might not only act as solvent but also, in all probability, participates in the catalytic reaction as reported that THF molecule could coordinate to metal center and dissociate from the metal center. 16 1,4-dioxane was a weak base like THF, coordinating to the metal center to form an intermediate adduct, which effectively inhibited the consecutive coordination of CHO, whereas on receiving the more electrophilic CO 2 molecule, the active metal center released 1,4-dioxane to form the carbonate unit.…”