Monomeric and dimeric manganese triazacyclononane complexes are immobilized onto, and activated by, solid carboxylates.

Styrene epoxidation rates and yields depend on complex nuclearity and support, and can be 50-fold that of the homogeneous complex.

Yields increase for e-withdrawing substituents, up to 100% yield and 1000 TON for cyanostyrene. This trend is counter to expectations and reflects inhibition by minor, ring-opening side products.

Optimizing conditions allows up to 75% yield of challenging bis-epoxides from divinylbenzene.