53759-17-4Relevant articles and documents
Chirality sensing of choline derivatives by a triple anion helicate cage through induced circular dichroism
Zuo, Wei,Huang, Zhe,Zhao, Yanxia,Xu, Wenhua,Liu, Zhihua,Yang, Xiao-Juan,Jia, Chuandong,Wu, Biao
supporting information, p. 7378 - 7381 (2018/07/06)
Chirality sensing of choline derivatives is achieved by a self-assembled, racemic triple anion helicate cage which exhibits induced circular dichroism (ICD) upon encapsulation of a chiral guest. The host-guest interactions were illustrated by NMR, crystal
Chiral conducting salts of nickel dithiolene complexes
Lieffrig, Julien,Jeannin, Olivier,Auban-Senzier, Pascale,Fourmigué, Marc
experimental part, p. 7144 - 7152 (2012/08/08)
Conducting and chiral [Ni(dmit)2] dithiolene salts were obtained by electrocrystallization of the radical [n-Bu4N][Ni(dmit) 2] salt in the presence of chiral, enantiopure trimethylammonium cations. Three different cations were investigated, namely, (R)-Ph(Me)HC- NMe3+, (S)-(tBu)(Me)HC-NMe3 +, and (S)-(1-Napht)MeHC-NMe3+, noted (R)-1, (S)-2, and (S)-3. Salts of 1:3 stoichiometry were obtained with (R)-1 and (S)-2, formulated as [(R)-1][Ni(dmit)2]3 and [(S)-2][Ni(dmit)2]3?(CH3CN)2. They both crystallize in the P212121 chiral space group, with three crystallographically independent complexes exhibiting different oxidation degrees. Another salt with 2:5 stoichiometry was isolated with (S)-3. The semiconducting character of the three salts (σ RT = 20-30 × 10-3 S cm-1) finds its origin in a strong electron localization, favored by the large number of crystallographically independent [Ni(dmit)2] complexes in these chiral structures and their association into weakly interacting dimeric or trimeric motifs. Racemic salts with the same cations, obtained only with difficulties with the tert-butyl-containing (rac)-2 cation, afforded similar trimerized structures. The observed unusual stoichiometry and strong charge localization is tentatively assigned to the size and anisotropic charge distribution of the cations.
Rhodium complexes with chiral counterions: Achiral catalysts in chiral matrices
Dorta, Romano,Shimon, Linda,Milstein, David
, p. 751 - 758 (2007/10/03)
The neutral complexes [Rh(I)(NBD)((1S)-10-camphorsulfonate)] (2) and [Rh(I)((R)-N-acetylphenylalanate)] (4) reacted with bis-(diphenylphosphino)ethane (dppe) to form the cationic Rh(I)(NBD)(dppe) complexes, 5 and 6, respectively, accompanied by their corresponding chiral counteranions. Analogously, 4 reacted with 4,4′-dimethylbipyridine to yield complex 7. Complexes 5 and 6 disproportionated in aprotic solvents to form the corresponding bis-diphosphine complexes 8 and 9, respectively. 8 was characterized by an X-ray crystal structure analysis. In order to form achiral Rh(I) complexes bearing chiral countercations new sulfonated monophosphines 13-16 with chiral ammonium cations were synthesized. Tris-triphenylphosphinosulfonic acid (H3TPPS, 11) was used to protonate chiral amines to yield chiral ammonium phosphines 14-16. Thallium-tris-triphenylphosphinosulfonate (Tl3TPPS, 12) underwent metathesis with a chiral quartenary ammonium iodide to yield the proton free chiral ammonium phosphine 13. Phosphines 15 and 16 reacted with [Rh(NBD)2]BF4 to afford the highly charged chiral zwitterionic complexes [Rh(NBD) (TPPS)2][(R)-N, N-dimethyl-1-(naphtyl)ethylammonium] 5 (17) and [Rh(NBD)(TPPS)2][BF4] [(R)-N, N-dimethyl-phenethylammonium]6 (18), respectively. Complexes 5, 6, and 18 were tested as precatalysts for the hydrogenation of de-hydro-N-acetylphenylalanine (19) and methyl-(Z)-(α) -acetoamidocinnamate (MAC, 20) under homogeneous and heterogeneous (silica-supported and self-supported) conditions. None of the reactions was enantioselective.
