Self-supported rhodium catalysts based on a microporous metal–organic framework for polymerization of phenylacetylene and its derivatives†
A series of heterogeneous metal–organic framework (MOF)-supported rhodium (Rh) hybrid catalysts with varying amounts of Rh are first applied to the coordination polymerization of phenylacetylene and its derivatives with or without cocatalysts in different organic solvents under a nitrogen atmosphere or in water media under an air atmosphere. In comparison with the known homogeneous and heterogeneous Rh catalysts, these MOF-supported Rh catalysts exhibit not only a channel confinement effect on the polymer molecular weight distribution but also a more remarkable cooperation effect, polar solvent acceleration effect, “on water” effect, and cocatalyst acceleration effect on the catalytic activity. As a result, these heterogeneous Rh catalysts have the advantages of an extremely high activity of up to 1.5 × 107 g molRh−1 h−1, cis-selectivity of up to 99%, and reusability of up to 10 times, affording cis-transoidal PPAs and their functional derivatives having single-handed helical conformation or aggregation-induced emission properties with moderate molecular weights and narrow molecular weight distributions. As far as we are aware, such extremely efficient Rh catalysts as well as multiple reusable heterogeneous Rh catalysts have never been reported.