Novel enantioselective photocatalysis by chiral, helical ruthenium(II) complexes
Abstract
The enantioselective photoreduction of the helical substrates of rac-[Co(acac)3](acac –= acetylacetonato) and rac-[Co(edta)]–(edta4–= ethylenediaminetetraacetato) with the newly synthesized helical photocatalysts Δ-(or rac)-[Ru[Menbpy)32+{Menbpy = 4,4′-bis[(1R,2S,5R)-(–)-menthoxycarbonyl]-2,2′-bipyridine}, and Λ-(or Δ)-[Ru{(S or R)-PhEtbpy}3]2+{(S or R)-PhEtbpy = 4,4′-bis[(S)-(–) or (R)-(+)-1-phenylethylaminocarbonyl]-2,2′-bipyridine} was realized in the helical-shape recognition reaction with a maximum enantiomer rate ratio (KΔ;/KΛ) of 14.7 in 90%v/v EtOH-H2O at 25 °C.