Highly Active and Selective Ru‐PNH Catalyst in Aerobic Oxidation of Benzyl Amines.

Set of [Ru(η6‐cymene)(R)XCl] (R=L1SnCl, L1GeCl L2PPh2, X=Cl or SnCl3, L1=[2‐(CH2NEt2)‐4,6‐(tBu)2C6H2]−, L2=2,6‐iPr2‐C6H3‐NH−) catalysts was tested in aerobic oxidations of primary amines. The activity of studied catalysts depends on the charge of the Ru atom that has been influenced either by donating ligands R or by character of X. Typical Ru/P catalyst [Ru(η6‐cymene)(L2PPh2)Cl2] (3) with least negative charge on the Ru atom has been observed as the most effective. The design of the phosphine ligand L2 containing amino‐phosphine PNH moiety provided efficient anchoring of complex 3 to silica gel via hydrogen bonding of the PNH functional group to SiO2 to give heterogeneous catalyst 3‐silica. This complex has been also efficiently tested in aerobic oxidation as recyclable catalyst with cumulative TON up to 6930. [ABSTRACT FROM AUTHOR]