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, P3HT copolymers containing functional groups (such as amino, imino, hydroxyl, etc.) are rarely reported because of inherent synthetic difficulties. Here P3HT copolymers bearing diverse functional pendants, which cannot be obtained by the direct block copolymerization of the corresponding monomers, were designed and facilely synthesized through the postpolymerization modification method. First, P3HT-b-poly(phenyl isocyanide) (P3HT-b-PPI) with pentafluorophenyl (PFP) ester was prepared in one-pot using Ni(dppp)Cl₂ as the catalyst. Then, through the postpolymerization 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. When pyrene pendants were introduced into PPI block, the obtained copolymer presented both aggregation-induced emission (AIE) and aggregation-caused quenching (ACQ) properties when methanol was added into its THF solution. As for the copolymer containing chiral pendants, an excess of right-handed helix of the PPI backbone was induced after annealing in toluene at 100 °C for 7 days, and left-handed helical bundles were formed by the self-assembly of the annealed copolymer 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 P3HT-b-PPI was obtained after postpolymerization modification of P3HT-b-PPI copolymer with glycol.
© 2018 American Chemical Society.

We herein report on the synthetic, structural, magnetic, and computational studies of six air-stable mononuclear Co(ii) complexes with distorted octahedral geometry from PyBox type ligands. Magnetic and theoretical studies reveal that these complexes all exhibit field-induced type single-molecule magnet behaviour and a large energy splitting between the ground and first excited Kramers doublets. Dynamic magnetic property analysis shows that the Raman relaxation process is the predominant process in all six compounds. For complexes 1, 2, 3, 5, and 6, the contribution of the direct process also existed. Importantly, the axial zero-field splitting parameter D in this series varies from positive to negative with the increased distortion of the octahedral geometry for the Co(ii) center, indicating that the fine-tuning of the molecular symmetry is an effective approach to manipulate the magnetic anisotropy in SIMs.
© 2017 the Partner Organisations.

Two pseudotetrahedral cobalt(II) complexes exhibiting slow magnetic relaxation under an applied direct-current field are investigated. The weak easy-plane anisotropy is accurately determined by high-field/high-frequency electron paramagnetic resonance spectroscopy as D = 2.57 cm(-1) and E = 0.82 cm(-1) for 1 and D = 5.56 cm(-1) and E = 1.05 cm(-1) for 2. In addition, hysteresis loops are observed for the two compounds at very low temperatures.

We herein report a "grafting from" strategy to immobilize optically active helical poly(phenyl isocyanide)s onto graphene oxide (GO) nanosheets. After covalently bounding alkyne-Pd(II) initiator onto GO nanosheets, the designed GO/polymer composites P1@GO and P1-b-P2@GO featuring single-handed helical poly(phenyl isocyanide)s growing from GO nanosheets were prepared by sequential addition of the chiral and achiral isocyanide monomers. Post-synthetic hydrolysis rendered P1-b-P3@GO to improve the hydrophilicity. The successful covalent bonding of poly(phenyl isocyanide)s chains onto GO nanosheets was certified by several cross evidences including scan emission microscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Circular dichroism spectra proved that the chiral information was introduced through the grafted single-handed helical polymer chains successfully. In addition, the resulting GO/polymer composites were explored as a chiral additive to induce enantioselective crystallization of racemic organic molecules. Preferential formation of rod-like L-alanine crystals was induced by composites bearing right-handed helical poly(phenyl isocyanide)s. The enantiomeric excess value of the induced crystals reached 76%, displaying the potential in future applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 2092–2103.
© 2017 Wiley Periodicals, Inc.

The synthesis of two linear terpy-based metallo-supramolecular fluorescent coordination polymers through 1:1 complexation of Zn2+ and Cd2+ ions with ditopic terpyridine ligand was reported. The dispersibility of P1 and P2 was significantly improved in organic solvent and water through the introduction of hydrophilic oligo-ethyoxy side chain. Two polymers displayed yellow light emission both in solution and the solid state due to the intra-ligand charge transfer (ILCT) between the d(10) metal ions and the conjugated spacer unit. These coordination polymers were explored as fluorescent chemosensors for detecting picric acid in aqueous media, displaying high sensitivity and good selectivity. In addition, test strips were prepared from these polymers and exhibited the practical potential of detecting the NACs pollutants in the outdoor water for public safety and security.

The living polymerization of a pentafluorophenyl (PFP) ester-functionalized phenyl isocyanide (1) using an alkyne-Pd(II) initiator affords well-defined poly(phenyl isocyanide) s with controlled molecular weights (Mns) and narrow molecular weight distributions (M-w/M(n)s). Post-polymerization modification of these polymers using alcohols and amines formed poly(phenyl isocyanide) s with defined ester and amide pendants. However, the polymers are optically inactive even when chiral alcohols and amines were used in the post-modification reactions. Interestingly, living polymerization of 1 using the Pd(II) initiator can be carried out in the presence of alcohols and amines in one-pot. Such one-pot polymerizations lead to the formation of well-defined helical poly(phenyl isocyanide)s in high yields with defined pendants through the linkage of an ester or amide. Remarkably, optically active helical poly(phenyl isocyanide) s with preferred handedness were facilely obtained when chiral alcohols and amines were used in one-pot polymerizations. The optical activities of the afforded helical polyisocyanides were relatively high and comparable to those prepared via polymerization of the corresponding enantiopure phenyl isocyanide monomers bearing chiral ester or amide groups.

A family of coil-rod-coil ABA triblock copolymers containing poly(3-hexylthiophene) (P3HT) and poly(hexadecyloxyallene) (PHA) were facilely synthesized in one-pot via three sequential living polymerizations of hexadecyloxyallene, 2-bromo-3-hexyl-5-chloromagnesiothiophene, and hexadecyloxyallene using the π-allylnickel complex as a single catalyst. Although the different monomers were polymerized under distinct polymerization mechanisms, the one-pot block copolymerization were revealed to proceed in a living/controlled chain-growth manner, affording well-defined PHA-b-P3HT-b-PHA triblock copolymers in high yields with controlled molecular weights and tunable compositions. The isolated triblock copolymers were found to self-assemble into well-defined supramolecular helical polymers with equivalent of right- and left-handedness. The helicity of the assemblies can be facilely tuned through the induction of chiral cholesteryl pendants introduced on the polyallene segments. Moreover, by using this synthetic method, amphiphilic P3HT triblock copolymers containing hydrophobic P3HT and hydrophilic poly(triethylene glycol allene) (PTA) were readily prepared. Such water-soluble PTA-b-P3HT-b-PTA triblock copolymer exhibited multiresponsiveness including solvent, pH, and temperature.
© 2016 American Chemical Society.

Facile synthesis of hybrid block copolymers containing two segments that cannot be synthesized under the same polymerization mechanism still remains a great challenge in the field of polymer synthesis. Here we report on one-pot synthesis of hybrid block copolymers containing conjugated poly(phenyleneethylene) (PPE) and stereoregular poly(phenyl isocyanide) (PPI) using palladium(II) complex as a single catalyst. Although the two blocks were polymerized via distinct polymerization mechanism, the block copolymerization were revealed to proceed in a living/controlled chain-growth manner, afforded PPE-b-PPI block copolymers in high yields with controlled molecular weights, narrow molecular weight distributions, and tunable compositions. By using this synthetic method, amphiphilic PPE-b-PPI block copolymers containing hydrophobic PPE and hydrophilic PPI segments were facilely prepared. Such block copolymer can self-assembly into well-defined supramolecular structure in selective solvents. In addition, the one-pot block copolymerization method can be applied to the preparation of other hybrid block copolymers such as PPE-b-poly(1-isocyanohexadecane) (PPE-b-PIH) and PPE-b-poly(quinoxaline-2,3-diyl) (PPE-b-PQD) under living/controlled chain-growth manners.

We herein report the synthesis of fluorescent silicon nanoparticles (F-SiNPs) with uniformly small sizes and stable fluorescence, and further preparation of F-SiNPs/poly(N-isopropylacrylamide) (F-SiNPs/PNIPAM) composite hydrogels by in situ polymerization. This type of hydrogel displayed visible thermal-sensitive phase transition properties. Upon heating, the fluorescence intensity of the hydrogels decreased sharply beyond the lower critical solution temperature (LCST) of PNIPAM. The process of fluorescence quenching and recovery was reversible after repeated heating and cooling cycles. This result suggests that the present organic/inorganic hybrid F-SiNPs/PNIPAM hydrogels will have potential applications in visual detection as fluorescence-based temperature sensors.
© 2016 The Royal Society of Chemistry.

In this study, we report the synthesis of five one-dimensional Zn(ii)-based metallo-supramolecular polymers P0-4 through 1:1 complexation of Zn(SO₃CF₃)₂ or Zn(ClO₄)₂ with ditopic ligands L^0-4 which contain two pyridine-dioxazole (pybox) units connected by a rigid conjugated oligo(1,4-phenylene) linker. The new Zn(ii)-based polymers displayed relatively high quantum yields in solution and the solid state and showed tunable luminescent colors from blue to yellow owing to the conjugation effect of the ligand and the intra-ligand charge transfer (ILCT) between the coordination site and the chromophore of the ligand. Moreover, the polymer solution could exhibit white light emission by simply regulating the metal/ligand ratio or mixing different polymers. The polymers have been further explored as fluorescent chemosensors (FCs) for detecting nitroaromatic explosives. Among others, P1 possessed the highest capability for detecting picric acid (PA).
© 2016 the Partner Organisations.