Yttrium-Catalyzed Synthesis of Bipyridine-Functionalized AB-Block Copolymers: Micellar Support for Photocatalytic Active Rhenium-Complexes

Herein, ortho-methylated bipyridines are introduced as initiators in 2-aminoalkoxy-bis (phenolate) yttrium complexes. For this C−H bond activation (ONOO)^tBuY(CH₂TMS)(thf) (1) (TMS=trimethylsilyl) is reacted with the respective bipyridine to obtain complexes (ONOO)^tBuY(6-Me₂bpy) (2) and (ONOO)^tBuY(6-Mebpy) (3). Both complexes were tested first in rare-earth metal-mediated group-transfer polymerization of 2-vinylpridine (2VP). Complex 3 was further tested in block copolymerizations of 2VP and diethyl vinylphosphonate. The obtained initiator-P2VP-PDEVP-block copolymers can selectively react with Re(CO)₅Cl at their bipyridine end-group. The obtained rhenium functionalized block copolymers are able to self-assemble to unimodal micelles in water, representing a possible carrier for hydrophobic metal containing complexes into cells. Furthermore, the Re-block copolymers sustain activity in the photocatalytic homogeneous CO₂ reduction and their performance exceed the catalytic activity of the analogue polymer-free system [Re(CO)₃(6-Mebpy)Cl] (4).