Greater than the Sum of Its Parts: A Heterodinuclear Polymerization Catalyst

Homodinuclear
catalysts have good precedent for epoxide and carbon
dioxide/anhydride copolymerizations; in contrast, so far pure heterodinuclear
catalysts are unknown. The synthesis and properties of a heterodinuclear
Zn­(II)/Mg­(II) complex coordinated by a symmetrical macrocyclic ligand
are reported. It shows high polymerization selectivity, control, and
significantly greater activity compared to either of the homodinuclear
analogues or any combinations of them. Indeed, compared to a 50:50
mixture of the homodinuclear complexes, it shows 5 times (CO2/epoxide) or 40 times (anhydride/epoxide) greater activity.