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Heterometallic rare earth metal-zinc complexes are highly active in catalyzing the cycloaddition of CO 2 with epoxides under amibient conditions. Cooperation mode of two metal centers was investigated by computational study. • Synthesis and characterization of heterometallic rare earth metal-zinc complexes. • Catalytic study in cycloaddition of epoxides and CO 2. • Active and recyclable under ambient conditions. • Synergistic effect of the two metal centers confirmed by computational study. Three heterometallic rare earth metal-zinc complexes were synthesized and structurally characterized. They catalyzed the cycloaddition of CO 2 with epoxides at ambient temperature and pressure, which generated a wide range of cyclic carbonates in good yield (44–98%). This is the first rare earth metal-based homogenous catalysts, which are active and recyclable under ambient conditions. The synergistic effect of the two metal centers is evidenced by means of computational study. [ABSTRACT FROM AUTHOR]

Novel zinc(II) and cobalt(II) complexes containing tripodal mono(phenolate) ligands have been synthesized and characterized. The resulting mononuclear complexes act as efficient initiators in the polymerization of rac -lactide to provide the corresponding biodegradable poly(lactic acid). Most of these polymerizations proceeded in a controlled fashion, giving polymers with narrow polydispersities and experimental molecular weights in good agreement with calculated values. [ABSTRACT FROM AUTHOR]