Products Cited in Publications Worldwide Rhodium(III) Werner Complexes with 1,2-Diphenylethylenediamine Ligands: Syntheses, Structures, and Applications as Chiral Hydrogen Bond Donor Catalysts and Agents for Enantiomer Purity Determinations

Rhodium(III) Werner Complexes with 1,2-Diphenylethylenediamine Ligands: Syntheses, Structures, and Applications as Chiral Hydrogen Bond Donor Catalysts and Agents for Enantiomer Purity Determinations

Aaron R. Wegener; Subrata K. Ghosh; Nattamai Bhuvanesh; Joseph Reibenspies; John A. Gladysz

DOI:

Abstract

Reactions of RhCl3 and (S,S)-1,2-diphenylethylenediamine (S,S-dpen) in DMSO at 140 °C give Λ-[Rh(S,S-dpen)3]3+3Cl− (Λ-(S,S)-43+3Cl−) in 76 % yield. When CH2Cl2/water suspensions are treated with 1.0 equiv. of Na+ B(C6F5)4− or Na+ B(3,5-C6H3(CF3)2)4−, the mixed salts Λ-(S,S)-43+2Cl−B(aryl)4− can be isolated from the organic layers (95–91 %). A wide variety of mixed and non-mixed salts involving these and other anions (BF4−, ClO4−, I−) are also prepared. The lipophilic salts are highly enantioselective catalysts for the Michael addition of dimethylmalonate to trans-ß-nitrostyrene (acetone, 0 °C; 92–85 % ee). The crystal structures of seven solvated salts are determined, and hydrogen bonding between the trications and anions or solvate molecules analyzed. There is a notable affinity of chloride anions for the C3 face of Λ-(S,S)-43+, which features three synperiplanar NH groups. Λ-(S,S)-43+2I−B(C6F5)4− is an excellent chiral solvating agent for determining enantiomeric purities of chiral organic molecules with hydrogen bond accepting functional groups (11 mol% (average), CDCl3).

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Rhodium(III) chloride trihydrate

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