Highly Active Multidentate Alkyne Metathesis Catalysts: Ligand-Activity Relationship and Their Applications in Efficient Synthesis of Porphyrin-Based Aryleneethynylene Polymers

A series of tris(arylmethyl)ammonium-coordinated molybdenum(VI) propylidyne catalysts was synthesized. Such N-quarternized multidentate catalysts showed high robustness, strong resistance to small alkyne polymerization and significantly enhanced catalytic activity compared to their corresponding tris(arylmethyl) amine-based analogues. The high activity of these new catalysts also enabled the efficient synthesis of ethynylene-bridged porphyrin-based arylene ethynylene polymers via alkyne metathesis, which represents a highly efficient, defect-free, viable approach for the synthesis of this class of intriguing polymers.