Synthesis of Chiral Cationic (Diimino‐ and diaminodiphosphane)ruthenium Complexes and Their Applications in Catalytic Oxidation − Crystal Structures of cis ‐[RuCl(py){κ 4 ‐Ph 2 PC 6 H 4 CH=NC 6 H 10 N=CHC 6 H 4 PPh 2 }]BF 4 and cis ‐[RuCl(py){κ 4 ‐Ph 2 PC 6 H 4 CH=NC 6 H 10 N(H)CH 2 C 6 H 4 PPh 2 }]BF 4

Halide abstraction of trans ‐[RuCl 2 {κ 4 ‐(1 R ,2 R )‐PNNP}] {(1 R ,2 R )‐PNNP = (1 R ,2 R )‐ N , N′ ‐bis[2‐(diphenylphosphanyl)benzylidene]‐1,2‐diiminocyclohexane} and trans ‐[RuCl 2 {κ 4 ‐(1 R ,2 R )‐P(NH)(NH)P}] {(1 R ,2 R )‐P(NH)(NH)P = (1 R ,2 R )‐ N , N′ bis[2‐(diphenylphosphanyl)benzylidene]‐1,2‐diaminocyclohexane} with AgBF 4 in acetonitrile at ambient temperature gave cis ‐[RuCl(CH 3 CN){κ 4 ‐(1 R ,2 R )‐PNNP}][BF 4 ] ( 1 ) and cis ‐[RuCl(CH 3 CN){κ 4 ‐(1 R ,2 R )‐P(NH)(NH)P}][BF 4 ] ( 2 ), respectively. When 1 was refluxed in pyridine (py), the coordinated CH 3 CN was replaced by pyridine to form cis ‐[RuCl(py){κ 4 ‐(1 R ,2 R )‐PNNP}][BF 4 ] ( 3 ). However, when 2 was refluxed in pyridine, one of the amino moieties (−CH 2 −NH−)was oxidized to an imino moiety (−CH=N−) with concomitant displacement of the coordinated CH 3 CN by pyridine to produce cis ‐[RuCl(py){κ 4 ‐(1 R ,2 R )‐P(N)(NH)P}][BF 4 ] ( 4 ). The structures of 3 and 4 were ascertained by X‐ray crystallography. Compounds 1 − 4 are effective catalysts for the epoxidation of various olefins with air. A turnover frequency of up to 733 h −1 and an enantiomeric excess of up to 24% were obtained for the epoxidation of styrene catalysed by 2 . Compound 2 can also catalyse the epoxidation, dehydrogenation and C−H activation of various olefins, alcohols and alkanes by tert ‐butyl hydroperoxide with high chemical selectivity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)