The robust, readily available cobalt(iii) trication [Co(NHCHPhCHPhNH)] is a progenitor of broadly applicable chirality and prochirality sensing agents.

When NMR spectra of chiral racemic organic molecules containing a Lewis basic functional group are recorded in the presence of air and water stable salts of the cobalt(iii) trication [Co((,)-NHCHPhCHPhNH)] (), separate signals are usually observed for the enantiomers (28 diverse examples, >12 functional groups). Several chiral molecules can be simultaneously analyzed, and enantiotopic groups in prochiral molecules differentiated (16 examples). Particularly effective are the mixed bis(halide)/tetraarylborate salts Λ- 2XBAr (X = Cl, I; BAr = B(3,5-CH(CF))), which are applied in CDCl or CDCl at 1-100 mol% (avg 34 and 14 mol%).

Syntheses of Families of Enantiopure and Diastereopure Cobalt Catalysts Derived from Trications of the Formula [Co(NHCHArCHArNH)].

Aerobic reactions of CoX (X = OAc, Cl) or Co(ClO) with (S,S)-1,2-diphenylethylenediamine [(S,S)-dpen] in CHOH, followed by HCl or HClO additions, give the diastereomeric lipophobic salts Λ-[Co((S,S)-dpen)]3Cl [Λ-(S,S)-13Cl] or Δ-(S,S)-13ClO (60-65%) with high degrees of selectivity. Anion metatheses (room temperature) and equilibrations (charcoal, CHOH, 70 °C) show that the former is more stable than Δ-(S,S)-13Cl, and the latter is more stable than Λ-(S,S)-13ClO. Additional anion metatheses lead to large families of lipophilic salts Λ- and Δ-(S,S)-12XX' [X/X' = Cl/BAr [BAr = B(3,5-CH(CF))], PF/BAr, BF/BAr, PhBF/BAr, Cl/BAr [BAr = B(CF)], BAr/BAr, BAr/BAr, BF/BF, PF/PF].

Octahedral Werner complexes with substituted ethylenediamine ligands: a stereochemical primer for a historic series of compounds now emerging as a modern family of catalysts.

As reported by Alfred Werner in 1911-1912, salts of the formally D symmetric [Co(en)] (en = ethylenediamine) trication were among the first chiral inorganic compounds to be resolved into enantiomers, the absolute configurations of which are denoted Λ (left handed helix) or Δ (right handed helix). After a >100 year dormant period during which few useful reactions of these substitution inert complexes were described, carbon substituted derivatives have recently been found to be potent catalysts for enantioselective organic synthesis. This review systematically outlines the fascinating range of stereoisomers that can arise, such as conformers associated with the five membered chelate rings (λ/δ), alignment modes of the C-C bonds with the C symmetry axis (lel/ob), geometric isomers (fac/mer), and configurational diastereomers (R/S) arising from carbon stereocenters.

Cobalt(III) Werner Complexes with 1,2-Diphenylethylenediamine Ligands: Readily Available, Inexpensive, and Modular Chiral Hydrogen Bond Donor Catalysts for Enantioselective Organic Synthesis.

In the quest for new catalysts that can deliver single enantiomer pharmaceuticals and agricultural chemicals, chemists have extensively mined the "chiral pool", with little in the way of inexpensive, readily available building blocks now remaining. It is found that Werner complexes based upon the D3 symmetric chiral trication [Co(en)3](3+) (en = 1,2-ethylenediamine), which features an earth abundant metal and cheap ligand type, and was among the first inorganic compounds resolved into enantiomers 103 years ago, catalyze a valuable carbon-carbon bond forming reaction, the Michael addition of malonate esters to nitroalkenes, in high enantioselectivities and without requiring inert atmosphere conditions. The title catalysts, [Co((S,S)-dpen)3](3+) ((S,S)-3 (3+)) 3X(-), employ a commercially available chiral ligand, (S,S)-1,2-diphenylethylenediamine.