Controlled Synthesis And Self-assembly Of Helical Poly(Phenyl Isocyanide)s And Its Block Copolymers With Poly(3-hexylthiophene)

New synthetic methods are of great significance in enabling access to valuable compounds and materials.Although conjugated poly?3-hexylthiophene??P3HT?has been widely investigated,P3 HT copolymers containing functional groups?such as amino,imino,hydroxyl,etc.?are rarely reported because of inherent synthetic difficulties.Here P3 HT copolymers bearing diverse functional pendants,which cannot be obtained by the direct block copolymerization of the corresponding monomers,were designed and facilely synthesized through post-polymerization modification method.Firstly,P3HT-bpoly?phenyl isocyanide??P3HT-b-PPI?with pentafluorophenyl?PFP?ester was prepared in one-pot using Ni?dppp?Cl₂ as the catalyst.Then,through the post-polymerization modification of the copolymer with alcohols and amines,P3HT-b-PPIs copolymers bearing defined functional groups were facilely obtained.The introduction of functional pendants endowed P3HT-b-PPIs copolymers with diverse functionalities.As for the copolymer containing chiral pendants,it became optically active after annealing in toluene at 100 �C for 7 days and self-assembled into helix in THF.Meanwhile,the copolymer containing PEG pendants was amphiphilic and could self-assembled into worm-like or spherical structures in different solutions.In addition,cross-linked P3HTb-PPI was obtained after post-polymerization modification of P3HT-b-PPI copolymer with glycol.Amphiphilic poly?3-hexylthiophene?-block-poly?phenyl isocyanide?s?P3HT-b-PPI?copolymers composed of hydrophobic ?-conjugated P3 HT and hydrophilic optically active helical PPI were prepared in one-pot using Ni?dppp?Cl₂ as a single catalyst.Taking advantage of the crystallization of P3 HT and the chirality of helical PPI segment,the block copolymers were found to self-assembly into well-defined helical supramolecular polymers in selective solvents,and realized the chirality transfer and amplification from polymer to supramolecular assemblies.The crystallization driven asymmetric selfassembly?CDASA?of the block copolymer in toluene and isopropanol?v/v = 4/6?lead to the formation of cylinder-like,single-handed helical micelles with P3 HT in core and PPI in corona through both the self-seeding and seed-growth methods.The living nature of CDASA rendered the cylinder-like helical micelles have controlled lengths,narrow length distributions and defined helicity as revealed by systematically atomic force microscope?AFM?,transmission electronic microscope?TEM?,and circular dichroism?CD?analyses.CDASA of the block copolymers induced intriguingly white-light emission although the copolymer only containing a P3HT-dye.Moreover,the helical micelles prepared by CDASA also exhibited an interesting circularly polarized luminescence?CPL?.The handedness and asymmetric factor of the induced CPL were tunable and respectively depending on the helicity and the length of the cylinder-like helical micelles.Controlled synthesis of single-handed helical polymer from achiral monomer is still a great challenge.In this work,we report two chiral Pd?II?catalysts bearing commercial available R-or S-2,2'-bis?diphenylphosphino?-1,1'-binaphthalene?R-or S-BINAP?ligands.Polymerization of achiral phenyl isocyanide?A-1?by S-BINAP/Pd?II?afforded a single right-handed helical poly?phenyl isocyanide?s in high yields with controlled molar mass?Mns?and narrow molar mass distributions?Mw/Mns?.While the RBINAP/Pd?II?catalyst lead to the formation of a single left-handed helix under the same condition.The single-handed helices were convinced by circular dichroism?CD?,UV-vis analyses and directly atomic force microscope?AFM?observations as well.Moreover,the chiral Pd?II?catalysts showed enantiomer-specific on polymerizations of isocyanides enantiomers?L-and D-1?,although the chiral center is remote from the polymerization site.S-BINAP/Pd?II?can effectively promote the living polymerization of L-1,afforded a right-handed helical poly-L-1m?S?,while failed on the polymerization of the D-1 enantiomer and the D/L-1 racemate under the same condition.Accordingly,RBINAP/Pd?II?can only catalyze the polymerization of D-1 enantiomer.In this paper,the copolymer P3HT-b-PPI with pentafluorophenyl ester was synthesized in one-pot using Ni?dppp?Cl₂ as the catalyst,and through postpolymerization modification with functional alcohols and amines.A series of helical P3HT-b-PPI copolymers composed of semi-conducting P3 HT and optically active helical PPI were asymmetrically self-assembled into cylinder-like helical micelles with controlled handedness,uniform lengths and widths vis living CDASA strategy through both selfseeding and seed growth methods.We developed a family of chiral catalysts of R-or SBINAP/Pd?II?.The polymerization of phenyl isocyanides through helix-sense-specific and enantiomer-specific living polymerizations using chiral catalysts afforded singlehanded helical poly?phenyl isocyanide?.