Convenient Synthesis and Characterization of the Chiral Complexes cis- and trans-[Ru((SS)-Prⁱpybox)(py)₂Cl]PF₆ and [Ru((SS)-Prⁱpybox)(bpy)Cl]PF₆

Abstract

The chiral oxazoline complexes cis- and trans-[Ru((SS)-Pr(i)pybox)(py)(2)Cl]PF(6) were prepared from the common precursor trans-[Ru((SS)-Pr(i)pybox)(py)Cl(2)], and all three complexes were spectroscopically and structurally characterized. The complex cis-[Ru((SS)-Pr(i)pybox)(py)(2)Cl]PF(6) crystallized in P2(1)2(1)2(1) with Z = 4, a = 8.396(2) Å, b = 18.396(3) Å, c = 20.954(3) Å, and R = 0.039 for 4131 reflections. The complex trans-[Ru((SS)-Pr(i)pybox)(py)(2)Cl]PF(6) crystallized in P2(1) with Z = 2, a = 10.110(2) Å, b = 13.566(2) Å, c = 12.043(2) Å, beta = 106.10(2) degrees, and R = 0.039 for 3869 reflections. The precursor trans-[Ru((SS)-Pr(i)pybox)(py)Cl(2)] crystallized in P2(1)2(1)2(1) with Z = 8, a = 15.856(2) Å, b = 17.216(1) Å, c = 17.768(1) Å, and R = 0.030 for 5826 reflections. A related reagent, [Ru((SS)-Pr(i)pybox)(bpy)Cl]PF(6), was prepared by a more direct route and was also characterized. Aqua complexes were formed by hydrolysis of the chloride ligand in the bis(pyridine) complexes with retention of the stereochemistry. Electrochemical oxidation of the aqua complexes yielded oxo species which are formally ruthenium(IV). Reactions of the oxo complexes with the prochiral reductant, methyl p-tolyl sulfide led to stereoselective formation of the sulfoxide with enantiomeric excess of the R isomer ranging from 7% to 13%.

Ruthenium(II) Complexes with Chiral Tetradentate P2N2 Ligands Catalyze the Asymmetric Epoxidation of Olefins with H2O2

“…33,34 The aqua complexes [Ru(OH 2 )L 5 ] n+ are of particular interest, as their 2e oxidation can give oxo complexes of the type [Ru IV (O)L 5 ], which have been used in a number of stoichiometric and catalytic oxygen-transfer reactions with alkanes, 35 alkenes, 2c,36,37 alcohols, 38 phosphines, 39 and sulfides. 40 The electrochemistry of aqua complexes of ruthenium(II) has been investigated in great detail by Meyer, 37 Che, 41 and Takeuchi. 42 Thus, the aqua complex [RuCl(OH 2 )(1a-κ 4 P,N,N,P)] + (3a) is possibly related to the hypothetical ruthenium(IV) oxo species [RuCl(O)(1a-κ 4 P,N,N,P)] + , the putative intermediate in the catalytic epoxidation described below.…”

“…31 P NMR (101 MHz,CDCl3): δ -15.2 (s) (δ -16.5 was reported for (rac)-1c). 18 MS (EI): m/z 829 (M + , 98), 751 ([M -Ph] + , 40), 540 ([M -NdC-PPh2] + , 100). Other analytic and spectral data are as in ref 20.…”

Mono and dinuclear half-sandwich platinum group metal complexes bearing pyrazolyl-pyrimidine ligands: Syntheses and structural studies

“…The infrared spectra of the dinuclear complexes [13] Table 2. The dinuclear complex [18](PF 6 ) 2 shows a typical piano-stool geometry for the ruthenium atoms with the metal centers being coordinated by the aromatic ligand, a terminal chloride and a chelating N,N-ligand (Fig.…”

“…In many cases the charge transfer properties of these compounds justify this interest. Especially with these nitrogen donor ligands have been shown to be effective catalysts for oxidation reactions [11][12][13][14][15][16][17][18][19] and for ringopening metathesis polymerization [20] and recent studies of arene ruthenium complexes have shown that they are found to inhibit cancer cell growth [21][22][23][24][25][26], as non-linear optical (NLO) materials [27,28]. For a majority of the complexes studied, the metal centers are linked by a bridging ligand and the nature of the bridge has a fundamental influence on the electronic interaction between the metals and therefore on the characteristics of the material.…”

Synthesis, spectroscopic and electronic characterizations of two half sandwich ruthenium(II) complexes with 2-(2′-hydroxyphenyl)-benzoxazole and 4-picolinic acid ligands

“…Ruthenium complexes containing nitrogen donor ligands have been shown to be effective catalysts for oxidations reactions [1][2][3][4][5][6][7][8][9], and the ruthenium compound with oxazoline molecules have been shown to tune the properties of a metal catalyst [10][11][12][13][14][15].…”