Hybrid ruthenium ROMP catalysts based on an engineered variant of β-barrel protein FhuA ΔCVF(tev) : effect of spacer length.

A biohybrid ring-opening olefin metathesis polymerization catalyst based on the reengineered β-barrel protein FhuA ΔCVF(tev) was chemically modified with respect to the covalently anchored Grubbs-Hoveyda type catalyst. Shortening of the spacer (1,3-propanediyl to methylene) between the N-heterocyclic carbene ligand and the cysteine site 545 increased the ROMP activity toward a water-soluble 7-oxanorbornene derivative. The cis/trans ratio of the double bond in the polymer was influenced by the hybrid catalyst.