The chiral cationic complex [Ru(η1‐OAc)(CO)((R,R)‐Skewphos)(phen)]OAc (2R), isolated from reaction of [Ru(η1‐OAc)(η2‐OAc)(R,R)‐Skewphos)(CO)] (1R) with phen, reacts with NaOPiv and KSAc affording [RuX(CO)((R,R)‐Skewphos)(phen)]Y (X=Y=OPiv 3R; X=SAc, Y=OAc 4R). The corresponding enantiomers 2S‐4S have been obtained from 1S containing (S,S)‐Skewphos. Reaction of 2R and 2S with (S)‐cysteine and NaPF6 at pH=9 gives the diastereoisomers [Ru((S)‐Cys)(CO)(PP)(phen)]PF6 (PP=(R,R)‐Skewphos 2R‐Cys; (S,S)‐Skewphos 2S‐Cys). The DFT energetic profile for 2R with (S)‐cysteine in H2O indicates that aquo and hydroxo species are involved in formation of 2R‐Cys. The stability of the ruthenium complexes in 0.9 % w/v NaCl solution, PBS and complete DMEM medium, as well as their n‐octanol/water partition coefficient (logP), have been evaluated. The chiral complexes show high cytotoxic activity against SW1736, 8505 C, HCT‐116 and A549 cell lines with EC50 values of 2.8–0.04 μM. The (R,R)‐Skewphos derivatives show higher cytotoxicity compared to their enantiomers, 4R (EC50=0.04 μM) being 14 times more cytotoxic than 4S against the anaplastic thyroid cancer 8505 C cell line.

The cationic achiral and chiral terpyridine diphosphine ruthenium complexes [RuCl(PP)(tpy)]Cl (PP = dppp (1), (R,R)-Skewphos (2) and (S,S)-Skewphos (3)) are easily obtained in 85-88 % yield through a one-pot synthesis from [RuCl 2 (PPh 3 ) 3 ], the diphosphine and 2,2':6',2''-terpyridine (tpy) in 1-butanol. Treatment of 1-3 with NaPF 6 in methanol at RT affords quantitatively the corresponding derivatives [RuCl(PP)(tpy)]PF 6 (PP = dppp (1 a), (R,R)-Skewphos (2 a) and (S,S)-Skewphos (3 a)). Reaction of [RuCl 2 (PPh 3 ) 3 ] with (S,R)-Josiphos or (R)-BINAP in toluene, followed by treatment with tpy in 1-butanol and finally with NaPF 6 in MeOH gives [RuCl(PP)(tpy)]PF 6 (PP = (S,R)-Josiphos (4 a), (R)-BINAP (5 a))isolated in 78 % and 86 % yield, respectively. The chiral derivatives have been isolated as single stereoisomers and 3 a, 4 a have been characterized by single crystal X-ray diffraction studies. The tpy complexes with NaOiPr display high photocatalytic activity in the transfer hydrogenation (TH) of carbonyl compounds using 2-propanol as the only hydrogen donor and visible light at 30 °C, at remarkably high S/C (up to 5000) and TOF values up to 264 h À 1 . The chiral enantiomers 2, 2 a and 3, 3 a induce the asymmetric photocatalytic TH of acetophenone, affording (S)-and (R)-1-phenylethanol with 51 and 52 % ee, respectively, in a MeOH/2propanol mixture.

The cyclometalated acetate ruthenium complexes [Ru(C^N)(η2-OAc)(dppb)] (dppb = 1,4-bis(diphenylphosphino)butane; HC^N = 2-phenylpyridine 1, benzo[h]quinoline 2, 1-phenylpyrazole 3, 2-phenyl-2-oxazoline 4) are easily obtained in 58-74% yield through a one-pot synthesis from...