Synthesis, Characterization, and Reactivities of Molybdenum and Tungsten PONOP Pincer Complexes

A new series of molybdenum
and tungsten tricarbonyl pincer complexes,
bearing pyridine-based PONOP-type pincer ligands, have been synthesized
and fully characterized. Addition of HBF4·Et2O to these tricarbonyl complexes generated seven-coordinate molybdenum
and tungsten hydride complexes, and these compounds have been isolated
in good yields. These metal hydrides show fluxional behavior in solution.
The hydride ligands on these metal complexes are acidic in nature
and are readily deprotonated by bases. The molybdenum hydride complex
is shown to catalyze isomerization of 1-hexene to internal isomers
under mild conditions.

本研究合成了一系列新型吡啶基PONOP型钳形配体修饰的钼和钨三羰基钳形配合物，并对其进行了全面表征。向该类三羰基配合物中加入氟硼酸二乙醚合络合物（HBF4·Et2O），可得到七配位钼及钨氢化物配合物，上述化合物均可通过良好收率分离得到。该类金属氢化物在溶液中表现出流变行为。该类金属配合物上的氢配体本质呈酸性，可被碱快速脱质子。实验证实，该钼氢化物配合物可在温和条件下催化1-己烯异构为内烯烃异构体。