Ruthenium Complexes with Tetraphenylimidodiphosphinate: Syntheses, Structures, and Applications to Catalytic Organic Oxidation

Treatment of Ru(PPh3)3Cl2 with K(tpip) (tpip− = [N(Ph2PO)2]−) afforded Ru(tpip)(PPh3)2Cl (1), which reacted with 4-t-Bu-C6H4CN, SO2(g), and NH3(g) to give Ru(tpip)(PPh3)2Cl(4-t-BuC6H4CN) (2), Ru(tpip)(PPh3)2Cl(SO2) (3), and fac-[Ru(NH3)3(PPh3)2Cl][tpip] (4), respectively. Reaction of [Ru(CO)2Cl2]x with K(tpip) in refluxing tetrahydrofuran (THF) led to isolation of the K/Ru bimetallic compound K2Ru2(tpip)4(CO)4Cl2 (5). Photolysis of cis-Ru(tpip)2(NO)Cl in MeCN and wet CH2Cl2 afforded cis-Ru(tpip)2(MeCN)Cl (6) and cis-Ru(tpip)2(H2O)Cl (7), respectively. Refluxing 6 in neat THF yielded Ru(tpip)2(THF)Cl (8). Treatment of Ru(CHR)Cl2(PCy3)2 (Cy = cyclohexyl) with [Ag(tpip)]4 afforded cis-Ru(tpip)2(CHR)(PCy3) [R = Ph (9), OEt (10)]. Complex 9 is capable of catalyzing oxidation of alcohols and olefins with N-methylmorpholine N-oxide and iodosylbenzene, respectively. The crystal structures of 2−7 and 9 were determined.