Carborane as a tunable tag for Ru catalysts: generating an anion-appended recyclable and robust catalyst suitable for the noncovalent binding concept.

Ruthenium carbene complexes 9 with a closo-1,2-C(2)B(10)H(11) tag and 10 with an ionic nido-7,8-C(2)B(9)H(11) tag were synthesized. Both 9 and 10 are highly reactive catalysts for olefin metathesis reactions. Importantly, 10 is a robust and recyclable anion-appended catalyst that was suitable for noncovalent binding with many cationic resins. At least ten recycles were achieved for RCM of the selected substrate using 10 as the catalyst in ionic liquids.