Syntheses of Families of Enantiopure and Diastereopure Cobalt Catalysts Derived from Trications of the Formula [Co(NH2CHArCHArNH2)3]3+

Aerobic reactions of CoX 2 (X = OAc, Cl) or Co(ClO 4 ) 2 with (S,S)-1,2-diphenylethylenediamine [(S,S)-dpen] in CH 3 OH, followed by HCl or HClO 4 additions, give the diastereomeric lipophobic salts Λ-[Co((S,S)-dpen) 3 ] 3+ 3Cl - [Λ-(S,S)-1 3+ 3Cl - ] or Δ-(S,S)-1 3+ 3ClO 4 - (60-65%) with high degrees of selectivity. Anion metatheses (room temperature) and equilibrations (charcoal, CH 3 OH, 70 °C) show that the former is more stable than Δ-(S,S)-1 3+ 3Cl - , and the latter is more stable than Λ-(S,S)-1 3+ 3ClO 4 - . Additional anion metatheses lead to large families of lipophilic salts Λ- and Δ-(S,S)-1 3+ 2X - X' - [X/X' = Cl/BAr f [BAr f = B(3,5-C 6 H 3 (CF 3 ) 2 ) 4 ], PF 6 /BAr f , BF 4 /BAr f , PhBF 3 /BAr f , Cl/BAr f20 [BAr f20 = B(C 6 F 5 ) 4 ], BAr f /BAr f , BAr f20 /BAr f20 , BF 4 /BF 4 , PF 6 /PF 6 ]. Mixed salts of the formula Λ- and Δ-[Co((S,S)-NH 2 CHArCHArNH 2 ) 3 ] 3+ 2Cl - BAr f - are similarly prepared (Ar = 4-C 6 H 4 n-Bu, 4-C 6 H 4 Cl, 4-C 6 H 4 CF 3 , 4-C 6 H 4 OCH 3 , α-naphthyl, β-naphthyl, 2-C 6 H 4 OBn). The diastereotopic NHH' protons exhibit differen 1 H NMR signals; one shifts far downfield when X/X' = Cl/BAr f (δ ca. 8.0 vs 4.0 ppm). This is believed to arise from hydrogen bonding between the two Cl - anions and the two C 3 faces of the D 3 -symmetric trication, each of which feature three synperiplanar NH groups. When all of the anions are poor hydrogen-bond acceptors (e.g., BAr f - , BF 4 - , ClO 4 - ), equilibria favor Δ diastereomers.