Heteronuclear, Monomer-Selective Zn/Y Catalyst Combines Copolymerization of Epoxides and CO with Group-Transfer Polymerization of Michael-Type Monomers.

Terpolymerizations of cyclohexene oxide (CHO), CO, and the Michael-type monomer 2-vinylpyridine (2VP) are presented. The combination of two distinct polymerization mechanisms was enabled by the synthesis of a heterobifunctional complex (). Its β-diiminate zinc moiety allows the ring-opening copolymerization of CHO and CO, whereas the yttrium metallocene catalyzed the rare earth metal-mediated group-transfer polymerization of the polar vinyl monomer.

Synthesis of Lewis Acidic, Aromatic Aminotroponiminate Zinc Complexes for the Ring-Opening Polymerization of Cyclic Esters.

Three novel aminotroponiminate (ATI) zinc complexes I-III (I = [(Ph)ATI]Zn-N(SiMe), II = [(CH-2,6-CH/Ph)ATI]Zn-N(SiMe), and III = [(CH-2,6-CH(CH)/Ph)ATI]Zn-N(SiMe)) were synthesized and tested in the ring-opening polymerization of the lactones β- rac-butyrolactone (BBL) and rac-lactide (LA). The ligands, with two of them literature unknown, were readily obtained via a three-step synthesis from tropolone. Forming a five-membered metallacycle with zinc, the complexes were further structurally examined via single-crystal X-ray analysis and compared with that of the established, 6-ringed β-diiminate (BDI) complex IV ([CH(CMeNPh)]Zn-N(SiMe)).

CO-Controlled One-Pot Synthesis of AB, ABA Block, and Statistical Terpolymers from β-Butyrolactone, Epoxides, and CO.

Terpolymerizations of (rac)-β-butyrolactone (BBL), cyclohexene oxide (CHO), and carbon dioxide were realized in one-pot reactions utilizing a Lewis acid BDI-Zn-N(SiMe) (1) catalyst. The type of polymerization can be regulated and switched between ring-opening polymerization (ROP) of BBL and CHO/CO copolymerization by the presence of CO in the reaction mixture. Applying 3 bar CO to the three-component system leads to similar reaction rates for copolymerization and ROP and therefore to a terpolymer with a statistical composition, whereas 40 bar CO affords exclusive copolymerization of CHO/CO.