Ruthenium(<scp>II</scp>) Complexes Bearing Schiff Base Ligands for Efficient Acceptorless Dehydrogenation of Secondary Alcohols^†

Abstract

Four ruthenium(II) complexes 1—4 [RN=CH‐(2,4‐( t Bu) 2 C 6 H 2 O)]RuH(PPh 3 ) 2 (CO) (R = C 6 H 5 , 1; R = 4‐MeC 6 H 4 , 2; R = 4‐ClC 6 H 4 , 3; R = 4‐BrC 6 H 4 , 4) bearing Schiff base ligands were prepared by treating RuHClCO(PPh 3 ) 3 with RN=CH‐(2,4‐( t Bu) 2 C 6 H 2 OH (L1—L4) in the presence of triethylamine. Their structures were fully characterized by elemental analysis, IR, NMR spectroscopy and X‐ray crystallography. These Ru(II) complexes exhibit high catalytic performance and good functional‐group compatibility in the acceptorless dehydrogenation of secondary alcohols, affording the corresponding ketones in 82%—94% yields.

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