No abstract

A new triphenylamine-alt-fluorene conjugated polymer with hexaphenylbenzene and pyrene for near-infrared electrochromism supported by DFT calculation and simulated spectra.

In this study, we synthesized a linear copolymer, poly(g-propargyl-L-glutamate-graft-cyclodextrin) (PPLG-g-CD), through Huisgen [2 + 3] cycloadditions (click reactions) of monoazido-functionalized bcyclodextrin (N 3 -CD) with the propargyl side chains, obtaining a self-assembling structure with a highly stable a-helical conformation and water-solubility. We used Fourier transform infrared spectroscopy, solid state nuclear magnetic resonance spectroscopy, wide-angle X-ray diffraction, and circular dichroism analyses in the solid state and in solution to characterize the transformations of the secondary structures between a-helix and b-sheet conformations. Temperature-dependent FTIR spectroscopic analyses revealed that the presence of the CD units on the PPLG side chain increased the stability of the a-helix conformation toward elevated temperatures, relative to that of pure PPLG. In addition, the presence of the CD cavities allowed the grafted polymers to form inclusion complexes with low-molecular-weight compounds, providing macromolecules with potential biomedical applications.

Novel conjugated polymers such as poly(phenylene-fluorene) P1 and poly(triphenylbenzene-fluorene) P2with hexaphenylbenzene (HPB) as a pending side group were prepared by Suzuki coupling using the dibromo monomers M1 and M2 with 9,9-dioctylfluorene-2,7-diboronic acid bis(1,3-propanediol) ester, respectively. The HPB moiety of P1 and P2 can be oxidatively cyclodehydrogenated with FeCl 3 in nitromethane, yielding polymers P3 and P4 with hexa-peri-hexabenzocoronene (i.e., nanographene) units.The cyclodehydrogenation of nanographene-containing polymers was confirmed by FT-IR spectroscopy. In addition, X-ray powder diffraction of both P3 and P4 revealed a polymer interlayer spacing of 1.3 nm being dominated by the nanographenes. The glass transition temperatures (T g s) of P1 and P2 were 202°C and 235°C, respectively, while both P3 and P4 with nanographenes possessed T g s higher than 300°C. Compared to P3, P4 with a triphenylbenzene moiety in its backbone can be well dispersed without aggregation in N-cyclohexyl-2-pyrrolidone (CHP), as confirmed by UV-Vis spectroscopy, photoluminescence spectroscopy (PL) and photoluminescence-excitation (PLE) maps.Scheme 1 The synthesis of HPB-containing monomers M1 and M2 as well as conjugated polymers P1 and P2. PaperPolymer Chemistry 6212 | Polym. Chem., 2016, 7, 6211-6219This journal is

A new approach for polytriarylamine (PTAA)assisted selective dispersion for single-walled carbon nanotubes (SWNTs) in a toluene solution has been developed. The triarylamine-based conjugated polymers are able to selectively wrap the SWNTs with specific chiral indices depending on their backbone structures (e.g., PTAA 12 , PTAA 12 -P, and PTAA 12 -BP) and side-chain functionality (e.g., PTAA 6 , PTAA 6 -alt-PTAA, and PTAA 12 -alt-PTAA). PTAA 12 exhibits highly selective wrapping for the (6,5) chirality from CoMoCAT (catalytic processes) SWNTs but low selectivity in a dispersion of HiPCO (high-pressure carbon monoxide) SWNTs. Therefore, the selection for HiPCO SWNTs has been further improved via PTAA 12 -alt-PTAA wrapping with alternating side chains and mainly exhibits a high affinity to (6,5) SWNTs with high chiral angles (≥24.5°). The wrapping conformation and binding energy of the polymer/(6,5) SWNTs were studied via molecular modeling, and the simulated results are in good agreement with the experimental data for the selective dispersion of (6,5) SWNTs.