@article { ISI:000354478700007, title = {Easy {\textquoteleft}filter-and-separate{\textquoteright} method for enantioselective separation and chiral sensing of substrates using a biomimetic homochiral polymer}, journal = {Chemical Communications}, volume = {51}, number = {43}, year = {2015}, month = {APR}, pages = {8931-8934}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

We present a polyfluorene appended with protected L-glutamic acid that exhibited a reversible alpha-helix/beta-sheet-like conformation and helical porous fibrous morphology mimicking the super-structure of proteins. The new homochiral polymer probe enabled efficient heterogeneous enantioselective separation and chiral sensing of a wide variety of substrates from their aqueous racemic mixture using an easy {\textquoteleft}Filter-and-Separate{\textquoteright} method.

}, issn = {1359-7345}, doi = {10.1039/c5cc01532d}, author = {Senthilkumar, T. and Asha, S. K.} } @article {46851, title = {Enantioselective separation using chiral amino acid functionalized polyfluorene coated on mesoporous anodic aluminum oxide membranes}, journal = {Analytical Chemistry}, volume = {92}, year = {2020}, month = {MAY }, pages = {6850-6857}, type = {Article}, abstract = {

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.

}, issn = {0003-2700}, doi = {10.1021/acs.analchem.9b04699}, author = {Nikam, Shrikant B. and Asha, S. K.} } @article {47660, title = {Enantioselective separation using chiral amino acid functionalized polyfluorene coated on mesoporous anodic aluminum oxide membranes (vol 92, pg 6850, 2020)}, journal = {Analytical Chemistry}, volume = {93}, year = {2021}, month = {JUL }, pages = {10388}, type = {Correction}, issn = {0003-2700}, doi = {10.1021/acs.analchem.1c02694}, author = {Nikam, Shrikant B. and Asha, S. K.} } @article {48710, title = {Exploring SiliaCat Pd-DPP as a recyclable heterogeneous catalyst for the multi-batch direct heteroarylation polymerization for P(NDI2OD-T2)}, journal = {Polymer Chemistry}, volume = {14}, year = {2023}, month = {JUN}, pages = {2803-2819}, type = {Article}, abstract = {

Donor-acceptor (D-A) conjugated polymers like P(NDI2OD-T2) are important constituents of the active layer of energy conversion devices like all-polymer solar cells. A cost-effective and environmentally amiable pathway for the synthesis of this and similar D-A polymers is highly desirable for the large-scale production of these materials. In this report we have combined two cost-effective approaches, namely, direct heteroarylation polymerization (DHAP) and a recyclable heterogeneous catalyst (SiliaCat Pd-DPP), for the multi-batch synthesis of P(NDI2OD-T2). The general applicability of the approach was first established with a series of conjugated small molecules based on naphthalene diimide and bithiophene derivatives (N1 to N6). The Meitlis hot filtration test and inductively coupled plasma-optical emission spectroscopy (ICP-OES) were conducted to estimate the quantity of leached palladium in the final reaction product. Catalyst recyclability up to five cycles was demonstrated for N1 with \<2 ppm leached palladium impurity. A comparison was made with the homogeneous catalyst Pd(2)dba(3) which indicated the presence of much higher levels of palladium impurity in the final product. The polymerization of P(NDI2OD-T2) was demonstrated using the regular monomers (NDIOD-Br-2 and bithiophene) and also using a modified monomer with activated bithiophene (naphthalene diimide substituted bithiophene) under DHAP conditions employing SiliaCat Pd-DPP as the recyclable heterogeneous catalyst. The modified monomer proved to be amenable to DHAP polymerization using SiliaCat Pd-DPP as the heterogeneous catalyst, which could be consecutively reused four times with reproducible molecular weights in the range of M-n/M-w: 27.1/49.0 to 33.5/61.3.

}, issn = {1759-9954}, doi = {10.1039/d3py00183k}, author = {Kakde, Navnath R. and Asha, S. K.} }