01818nas a2200157 4500008004100000022001400041245013700055210006900192260000900261300001400270490000700284520120200291100002401493700001701517856012601534 2020 eng d a0003-270000aEnantioselective separation using chiral amino acid functionalized polyfluorene coated on mesoporous anodic aluminum oxide membranes0 aEnantioselective separation using chiral amino acid functionaliz cMAY  a6850-68570 v923 a

Homochiral mesoporous anodic aluminum oxide membranes (AAO) were prepared by coating protected chiral D/L aspartic acid appended polyfluorene in the pores. These chiral AAO membranes successfully demonstrated enantioselective recognition and separation of a range of amino acids from their aqueous racemic mixture by simple filtration. Enantioselective separation was achieved by selective adsorption of one enantiomer from the aqueous racemic mixture into the chiral pores of the AAO membrane leaving the filtrate enriched with the other enantiomer. Extraction and quantification of the adsorbed amino acid (glutamic acid) demonstrated that 1 mg of homochiral polyfluorene could effectively extract about 3.5 mg of glutamic acid with 95% enantiomeric excess in 24 h. This is one of the highest enantiomeric excesses (ee %) and yields reported so far in the literature for a racemic mixture of glutamic acid. The pore size of the AAO membrane influenced the efficiency of separation with a reduction in pore size from 200 to 20 nm leading to reduced ee % (similar to 95% to similar to 28%). These results raise the possibility for a facile method to carry out enantioselective separation.

1 aNikam, Shrikant, B.1 aAsha, S., K. uhttps://library.ncl.res.in/content/enantioselective-separation-using-chiral-amino-acid-functionalized-polyfluorene-coated00626nas a2200145 4500008004100000022001400041245016100055210006900216260000900285300001000294490000700304100002400311700001700335856012800352 2021 eng d a0003-270000aEnantioselective separation using chiral amino acid functionalized polyfluorene coated on mesoporous anodic aluminum oxide membranes (vol 92, pg 6850, 2020)0 aEnantioselective separation using chiral amino acid functionaliz cJUL  a103880 v931 aNikam, Shrikant, B.1 aAsha, S., K. uhttps://library.ncl.res.in/content/enantioselective-separation-using-chiral-amino-acid-functionalized-polyfluorene-coated-006205nas a2200145 4500008004100000245013700041210006900178260000800247300001400255490000600269520561500275100002405890700001605914856012905930 2022 eng d00aEnantioselective separation of amino acids using chiral polystyrene microspheres synthesized by a post-polymer modification approach0 aEnantioselective separation of amino acids using chiral polystyr cMAR a257–2650 v23 a

The enantioselective separation of a racemic mixture of amino acids was achieved by chiral amino acid-modified polystyrene (PS) that was developed by a post-polymer modification approach. Styrene was polymerized using the reversible addition–fragmentation chain-transfer (RAFT) polymerization technique and further post-polymer modification was applied by Friedel–Crafts acylation reaction with chiral N-phthaloyl-l-leucine acid chloride to obtain the protected PS-l-Leu. The chiral PS (protected PS-l-Leu) was assembled into microspheres using a surfactant and was used for carrying out the enantioselective separation of amino acid racemic mixtures by enantioselective adsorption followed by a simple filtration process. Compared to as-precipitated chiral PS (protected PS-l-Leu) powder, the protected PS-l-Leu microspheres exhibited a better enantioselective separation efficiency (ee %). Furthermore, the protected PS-l-Leu was deprotected to obtain the amine-functionalized deprotected PS-l-Leu chiral PS, which was also assembled into microspheres and used for carrying out enantioselective separation. Deprotected PS-l-Leu-functionalized chiral PS microspheres could achieve up to 81.6 ee % for the enantioselective separation of a racemic mixture of leucine. This is one of the first reports of the synthesis of amino acid-modified chiral PS microspheres and their application to the simple filtration-based enantioselective separation of native amino acids from their racemic mixtures.

1 aNikam, Shrikant, B.1 aK, Asha, S. uhttps://library.ncl.res.in/content/enantioselective-separation-amino-acids-using-chiral-polystyrene-microspheres-synthesized