A novel enantiopure phenyl isocyanide (1) carrying l-proline derivative was designed and synthesized. Living polymerization of 1 using a alkyne-Pd(II) catalyst affording a series of helical poly-1ms with controlled molecular weights (Mns) and narrow molecular weight distributions (Mw/Mns) bearing l-proline ester as the pendants. Removed the protecting groups on the l-proline pendants lead to the formation of helical poly-1m-A. Very interestingly, the left-handed backbone of poly-1m was reversed to right-handed helix in poly-1m-A as revealed by circular dichroism (CD) and polarimetry. Optically active helical poly-1m-A showed excellent catalytic ability on asymmetric aldol reaction. Comparing to the small molecule (1-A) with similar structure, both the enantioselectivity and the diastereoselectivity of the aldol reaction were significantly enhanced. The enantiomeric excess (ee) and diastereomeric ratio (dr) values of the aldol reaction are up to 95% and >20/1, respectively. Moreover, the helical polyisocyanides catalyst can be easily recovered and reused in the aldol reaction at least four cycles without significant loss of its enantioselectivity and diastereoselectivity.

A family of sequence-defined ABC triblock copolymers composed of poly(3-hexylthiophene) (P3HT), poly(hexadecyloxylallene) (PHA), and poly(phenyl isocyanide) (PPI) blocks were facilely synthesized in one pot using Ni(II) complex as a single catalyst. Although the monomers of the three blocks are different than each other and were polymerized under distinct polymerization mechanisms, the one-pot sequential block copolymerization was revealed to proceed in a living/controlled chain-growth manner. The sequence of the blocks can be facilely tuned through the variation on the order of monomer feed additions. Thus, a series of triblock copolymers with defined sequences, controlled molecular weights (Mns), narrow molecular weight distributions (Mw/Mns), and tunable compositions can be readily prepared just by varying the initial feed ratios of monomers to the catalyst. Taking advantage of this synthetic method, amphiphilic triblock copolymers containing hydrophobic P3HT, hydrophilic poly(triethylene glycol allene), and hydrophilic PPI bearing triethylene glycol monomethyl ether chains were synthesized. Interestingly, such amphiphilic triblock copolymers exhibited tunable light emissions with response to various environmental stimuli such as solvent, pH, and temperature. Remarkably, white-light emission can be readily achieved in solution, gel, and also solid state.

A new Pd(II) initiator bearing an alkyne headgroup was designed and synthesized. Living polymerization of phenyl isocyanide using this Pd(II) initiator afforded well-defined alkyne-terminated helical poly(phenyl isocyanide) (PPI) with controlled molecular weights (Mns) and narrow molecular weight distributions (Mw/Mns). The alkyne end group of PPI coupled with azide-terminated random-coil poly(ethylene glycol) (PEG) via copper-catalyzed alkyne–azide cycloaddition (CuAAC) “click” chemistry formed a novel class of helix–coil block copolymer PPI-b-PEG. The alkyne-terminated PPI coupled with a PEG bearing azides on both the two chain ends afforded a helix–coil–helix triblock copolymer PPI-b-PEG-b-PPI. When optically active alkyne-terminated PPIs bearing L- or D-menthol ester pendants were used in the coupling reaction, optically active di- and triblock copolymers were facilely achieved, which exhibited an intense Cotton effect on circular dichroism (CD) spectra due to the one-handed helical conformation of the PPI segments. Moreover, a Pd(II) complex bearing two alkyne headgroups was designed and synthesized, which initiated the living polymerization of phenyl isocyanide that lead to the formation of well-defined PPI with two alkyne groups on the same chain end. Coupling this helical polymer with azide-terminated PEG via CuAAC “click” chemistry formed a helix–(coil)2 miktoarm star copolymer containing two random-coil PEG segments and one helical PPI block. The amphiphilic block and star polymers containing hydrophobic PPI and hydrophilic PEG segments were found to self-assemble into well-defined spherical nanoparticles in water. Interestingly, these supramolecular architectures showed excellent chiral recognition to dansyl modified L- and D-phenylalanine (L- or D-Phe-DNSP) in high enantiomeric selectivity.

Two novel enantiopure styrene derivatives (L- and D-1) bearing the chiral amide groups were designed and synthesized. The polymerization of these monomers using the reversible addition fragment transfer (RAFT) radical polymerization afforded a series of poly-L-1ms and poly-D-1ms in high yields with controlled molecular weights (Mns) and narrow molecular weight distributions (Mw/Mns). Interestingly, these polymers could adopt a stable helical conformation when the degree of the polymerization reached ca. 60 owing to the intramolecular hydrogen bonding between the adjacent repeating units as revealed by circular dichroism (CD) spectroscopy, UV-vis spectroscopy, and polarimetry. The helicity of these polymers could be tuned via solvent and temperature alterations. Increasing the temperature or the polarity of the solvents weakens the intramolecular hydrogen bonding, and thus the helical structure may transform to a random coil, endowing these polymers with multi-responsiveness. Moreover, such helical polymers could be further copolymerized with a cross linker, leading to the formation of a core cross-linked star polymer carrying the helical arms. Because of the chirality of the helical arms, the star polymer showed an excellent ability in enantioselective crystallization using racemic D/L-threonine as the model compounds. The enantiomeric excess (ee) of the induced crystals was up to 95%.

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 (Mw/Mns). 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.

Conjugated block copolymers have gained increasing interests in recent years. Development of a novel method for facile synthesis of conjugated block copolymers with desired structures and functions is greatly desired. In this mini review, we summarized the recent advances in one-pot synthesis of conjugated block copolymers containing π-conjugated polythiophene and helical polyisocyanide segments by using a nickel(II) complex as single catalyst. The sequential living polymerization of the two monomers proceeded in a controlled manner, affording expected block copolymers in high yields with controlled molecular weights (Mns) and narrow molecular weight distributions (Mw/Mns). By using this method, a family of block copolymers with expected structure and tunable compositions can be facilely prepared. Introducing functional groups onto the pendant, these block copolymers can exhibit interesting self-assembly property, tunable light emission and multi-responsiveness.

A novel strategy for the facile synthesis of ABC miktoarm polymers bearing poly(ε-caprolactone) (PCL), polystyrene (PS), and stereoregular helical poly(phenyl isocyanide) (PPI) blocks has been developed. A Pd(II) mid-functionalized PCL-b-PS block copolymer was first prepared in a controlled manner, which initiated the living polymerization of phenyl isocyanide, affording the well-defined ABC miktoarm star terpolymer.

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.

Polymeric assemblies are distinguished by ease of preparation, high drug-loading content, and long circulation time compared to small molecular, making them quite promising for cancerous diagnosis and therapy. However, the therapeutic efficacy of traditional nanocarriers with random coil surface is always proved to be less effective because of the existence of several systemic and cellular barriers or the low tissue penetration from nanocarrier itself. To fill this gap, we report a new class of oxidation and pH dual-responsive amphiphilic triblock copolymer: poly(l-lactic acid)(-IR780)-b-hydrophobic poly(phenyl isocyanide)-b-hydrophilic poly(phenyl isocyanide) (PLLA(-IR780)-HBPPI-HPPPI). In neutral aqueous solution, the copolymers could form onion-like spherical micelles with diameter of ∼84 nm and consisting of PEGylated single left-handed helical PPI corona, endowing them rapid cell membrane permeability and internalization (10–20 min) that had an analogous effect of cell penetrating peptides (CPPs). Moreover, the phenylboronic pinacol ester contained in the hydrophobic interlayer was stable under neutral and weak acid milieu and thus could minimize the premature drug leakage and systemic cytotoxicity. Upon exposure to H2O2, the interlayer was oxidized rapidly and accompanied by a hydrophobic–hydrophilic transition, which resulted in the releasing of encapsulated drugs and creating interconnected hydrophilic channels to the inner PLLA core at the same time. An enhanced drug release from PLLA core was then achieved by the acid-triggered micelle degradation. The degradation rates of micelles and release rates of drugs could be easily tuned by changing the concentration of H2O2 and the acidity. The hyperthermia induced by the micelles could increase to as high as ∼48 °C upon near-infrared (NIR) light irradiation (808 nm, 1 W cm–2) due to the introduction of NIR absorptive IR780 dyes. Combined with the effect of chemotherapeutics, fatal and irreversible damage to cancer cells was observed. The primary objective of this research was to address the growing need for an effective/rapid drug delivery system and programmed/sustained on-demand drug release. We speculate that the newly developed multifunctional integrated micelles with combined advantages can potentially be utilized as a promising approach to disease diagnosis and therapy.

In this contribution, we report on the facile synthesis of hybrid silica nanoparticles grafted with helical poly(phenyl isocyanide)s via both “grafting from” and “grafting to” strategies. First, triethoxysilanyl functionalized alkyne–Pd(II) initiator was anchored onto the surface of bare silica nanoparticles through silanization coupling reaction. Polymerization of phenyl isocyanide using the Pd(II)–anchored silica nanoparticles lead to the formation of hybrid nanoparticles grafted with helical poly(phenyl isocyanide)s. The surface-initiated polymerization was revealed to proceed in a living/controlled chain-growth manner, afforded the hybrid nanoparticles with controlled thickness. 31P NMR analysis indicated the initiation efficiency of the surface-anchored Pd(II) initiators is very high, and almost quantitative. The grafting density was determined to be ∼0.89 nm2/chain based on the thermal gravity analysis (TGA). Polymerization of optically active phenyl isocyanide bearing an l-alanine with a long decyl chain using the Pd(II)-anchored silica nanoparticles formed chiral hybrid nanoparticles grafted with helical poly(phenyl isocyanide) arms in preferred handedness. Second, the hybrid silica nanoparticles were prepared via “grafting to” strategy. Well-defined triethoxysilanyl terminated poly(phenyl isocyanide) was prepared in controlled manners. The polymer was grafted to the surface of bare silica nanoparticles via the silanization coupling reaction, afforded hybrid silica nanoparticles grafted with helical poly(phenyl isocyanide). TGA indicates the grafting density is ∼0.76 nm2/chain. Taking advantage of this synthetic method, left-handed helical poly(phenyl isocyanide) was grafted to the surface of silica nanoparticles, generated chiral hybrid silica nanoparticles with high optical activity. Such chiral nanoparticle exhibited good performance in enantioselective crystallization of racemic Boc-alanine. The enantiomeric excess (ee) of the induced crystal is up to 95%.

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.

Aggregation-induced emission (AIE) active tetraphenylethene (TPE) functionalized phenyl isocyanide (PI) derivatives, such as TPE pendent PI monomers (TPE-NC) and TPE-based Pd(II) catalysts (TPE-Cat. a and TPE-Cat. b) were synthesized. The corresponding linear (poly(TPE-NC)n) and four-armed (TPE-[poly(TPE-NC)m]4) conjugated polymers were subsequently prepared through the living polymerization of TPE-NC with TPE-Cat. a or TPE-Cat. b in THF, respectively. All of them have good solubility in common organic solvents, such as THF and CHCl3, and exhibited tunable AIE property, which can be facilely tuned through the variations on the concentration and the molecular weights (MWs) of the polymers. They also showed excellent thermal stability with a 5% of their weight loss as high as 380–405 °C and significant mass loss in the range of 350–650 °C. Stable helical assemblies could be formed by poly(TPE-NC)n at high concentration conditions. However, four-armed TPE-[poly(TPE-NC)m]4 could self-assemble into an apparent bumpy “caterpillar” like assembly, which was very different from the ordinary ones. Moreover, these conjugated polymers could be employed to generate a vapochromism phenomenon and act as good dispersants for carbon agglomerates in poor solvents. It is expected that this work can enrich the family of luminescent materials based on the helical poly(phenyl isocyanide) main chains and guide the future design of optical materials with attractive structures and special purposes, such as heat-resistant materials, security materials, and dispersed materials.

A facile construction of diverse polymeric nanostructures was reported by simple quaternization reaction and UV irradiation starting from the same rod–rod conjugated poly(4-isocyano-benzoic acid 5-(2-dimethylamino-ethoxy)-2-nitro-benzyl ester)-b-poly(3-hexylthiophene) (PPI(-DMAENBA)-b-P3HT) diblock copolymers, which were prepared by sequential living copolymerization of 4-isocyano-benzoic acid tert-butyl ester (PI) and 3-hexylthiophene (3HT) using Ni(dppp)Cl2 as a catalyst in a one-pot process with a subsequent chemical modification. The facile quaternization reaction and UV irradiation upon PPI(-DMAENBA)-b-P3HT could afford quaternized PPI(-DMAENBA)-b-P3HT (PPI(-QDMAENBA)-b-P3HT) and poly(4-isocyano-benzoic acid)-b-poly(3-hexylthiophene) (PPI(-AA)-b-P3HT) copolymers. Two different polymeric micellar supramolecular structures with cationic and anionic surface properties could be obtained by direct dispersion of positively charged PPI(-QDMAENBA)-b-P3HT and negatively charged PPI(-AA)-b-P3HT copolymers into water. Interestingly, the resultant PPI(-QDMAENBA/DMAENBA)-b-P3HT block copolymers with a 40% degree of quaternization were found to exhibit unique light emissions with the color transformed from luminous yellow to pink depending on the solvent ratio of THF and water used. An almost neutral and ordered thin film was achieved on the exact stoichiometric charge balance between these two types of oppositely charged micelles, which highlights the potential to incorporate conjugated copolymers into the assembled block copolymer micelles (BCMs) to yield multifunctional ordered films and relevant applications.

The design and synthesis of highly water-soluble conjugated block copolymers with multi-responsive properties are of great interest due to the copolymers’ potential as solution processable semiconductor materials. Herein, we report a one-pot synthesis of well-defined block copolymers containing conjugated poly(3-hexylthiophene) (P3HT) and poly(phenyl isocyanide) (PPI) bearing hydrophilic tri(ethylene glycol) monomethyl ether chains. These block copolymers have good solubility in water and exhibit excellent thermoresponsive behavior. The lower critical solution temperature (LCST) in water can be facilely tuned through varying the concentration or polymer composition. Moreover, the optical properties of the block copolymer are dependent on the solvents used owing to the distinct self-assembled structures. In CHCl3, the P3HT-b-PPI block copolymer exhibits pH-responsive behavior with the emission color changing between orange and blue upon alternate additions of trifluoroacetic acid and triethylamine. In addition, such block copolymers are revealed to be good materials for live cell imaging.

The development of novel synthetic methods for the facile preparation of well-defined stereoregular helical polyisocyanides and their block copolymers in a living/controlled fashion is of great interest. In this contribution, a family of air-stable alkylethynyl Pd(II) complexes was unexpectedly found to promote the living polymerization of phenyl isocyanide, affording poly(phenyl isocyanide)s with controlled molecular weights, narrow molecular weight distributions and high stereoregularity. Interestingly, such alkylethynyl Pd(II) complexes exhibit very high helix-sense-selectivity in the living polymerization of an optically active phenyl isocyanide bearing an L-alanine pendant with a long decyl chain, and a single handed helical poly(phenyl isocyanide) with controlled helical sense was selectively produced. Moreover, a Pd(II) complex bearing a hydroxyl group can initiate the living polymerization of both phenyl isocyanide and L-lactide in one-pot, leading to the formation of well-defined poly(phenyl isocyanide)-b-poly(L-lactic acid) copolymers in high yields with controlled molecular weights and tunable compositions. Although the two monomers were polymerized via distinct mechanisms, the block copolymerization was revealed to proceed under living/controlled manners.

A series of chiral aryl amide compounds bearing peptide pendants have been investigated as low molecular weight gelators. A mechanistic study reveals that complementary hydrogen bonding from peptide pendants is the main driving force for the formation of organogels. This new class of organogels can exhibit multi-stimuli-responsive behavior upon applying (1) thermal, (2) pH, (3) enantiomeric purity, and (4) fluoride anion stimuli. Enantiomeric purity as a new external stimulus displays sensitive stimuli-responsiveness; only 0.02 equiv. of the enantiomer can completely disassemble the gel aggregate. They will serve as excellent smart materials with potential applications in chiral sensors, recognition, and separation.

We report a new type of functional composite films by taking advantage of the interface-directed assembly between thiol groups functionalized poly(4-isocyano benzoic acid⋯pyridine-4-thiol)-b-poly(3-hexylthiophene) (PPI(–SH)-b-P3HT) conjugated copolymers and gold nanoparticles (Au NPs) at the chloroform/water interface. The PPI(–SH)-b-P3HT copolymers were synthesized through hydrogen bonding induced micellization and subsequent thiol–disulfide exchange reaction. Transmission electron microscopic (TEM) and atomic force microscopy (AFM) observations showed the film was uniform on a large scale and the integrity of surface morphology was not affected by the Au NPs concentration. Interestingly, the film substrate not only exhibited a strongly Au NPs concentration dependent surface-enhanced Raman scattering (SERS) activity but also allowed detection of model molecule, IR-792 perchlorate (IR-792), in the SERS measurement. This proof-of-concept suggests the interfacial assembly route is effective in integrating the properties of organic polymers and inorganic nanoparticles, and for further application.

An air-stable phenylethynyl Pd(II) complex containing a polymerizable norbornene unit was designed and synthesized. Such a Pd(II) complex can initiate the living/controlled polymerization of phenyl isocyanide, giving stereoregular poly(phenyl isocyanide)s in high yields with controlled molecular weights and narrow molecular weight distributions. The norbornene unit on the Pd(II) complex can undergo ring-opening metathesis polymerization (ROMP) with Grubbs’ second-generation catalyst, affording polynorbornene bearing Pd(II) complex pendants under a living/controlled manner. Interestingly, the Pd(II) complex pendants on the isolated polynorbornene are active enough to initiate the living/controlled polymerization of phenyl isocyanides, yielding well-defined brush-like copolymers with polynorbornene backbone and helical poly(phenyl isocyanide) as side chains. 31P NMR analyses indicate almost all the Pd(II) units on the polynorbornene participated in the polymerization, and the grafting density of the brush copolymer is high. Further studies revealed the brush copolymer can be readily achieved in one-pot via tandem catalysis. By using this method, a range of brush copolymers with different structures and tunable compositions were facilely prepared in high yields with controlled molecular weights and narrow molecular weight distributions. The synthesized brush copolymers were revealed to form worm-like cylindrical morphologies and helical rod architectures in film state by atomic force microscope observations.

Conjugated block copolymers with tunable properties have attract considerable research interests in recent years. Herein, we report a series of novel block copolymers containing conjugated poly(3-hexylthiophene) (P3HT) and poly(triethyl glycol allene) (PTA) segments which were synthesized in one pot using nickel complex as a single catalyst via distinct polymerization mechanisms. Interestingly, the P3HT-b-PTA diblock copolymers exhibit excellent thermoresponsive properties in water, and the lower critical solution temperature (LCST) is dependent on polymer concentration and the block ratio. Moreover, the diblock copolymers showed pH-responsive properties in CHCl3 with the emission color shuttled between orange and deep green upon the alternate additions of trifluoroacetic acid and triethylamine. Both P3HT-b-PTA and P3HT-b-PTA-b-P3HT block copolymers exhibit solvatochromism properties. The emission of the block copolymers can be facilely tuned through variation on solvents with the emission color spanned widely from red to blue. Very interestingly, white-light emission can be readily achieved from the P3HT-b-PTA-b-P3HT triblock copolymer in the mixture of THF and methanol with 1/3 volume ratio.

Polymerization of phenyl isocyanide using achiral Pd(II) initiator with the presence of chiral l- or d-lactide (l-LA or d-LA) as additive was found to proceed in helix-sense-selective manner. The polymerization of achiral phenyl isocyanide, 4-isocyanobenzoyl-2-aminoisobutyric acid decyl ester (1) by this method produced optically active helical poly-1m(L), whose chirality was solely come from the helical conformation without containing of any other chiral atoms. The added chiral LA can be facilely recovered and reused in the helix-sense-selective polymerizations without significantly loss of its chiral induction, and the chiral economy of the polymerization is high. When enantiomerically pure phenyl isocyanide bearing an R- or S-alanine pendent with a long n-decyl chain (1r or 1s) were polymerized by this method, the polymerization was found to proceed in a highly enantiomer-selective manner with one of the enantiomers preferentially polymerized over the antipode by a factor of 3.6. Single-handed helical polyisocyanides can be achieved when the chirality of the monomer was appropriately matched with the added LA.

A family of air-stable (phenylbuta-1,3-diynyl)palladium(II) complexes were designed and prepared in a facile synthetic procedure. Their structures were characterized by 1H and 13C NMR, MS, and X-ray analysis. These Pd complexes were revealed to efficiently initiate the polymerization of phenyl isocyanides in a living/controlled chain growth manner, which led to the formation of poly(phenyl isocyanide)s with controlled molecular weights and narrow molecular weight distributions. 13C NMR analysis indicated the isolated poly(phenyl isocyanide) was of high stereoregularity. The Pd unit at the end of the polymer chain could undergo further copolymerization with phenyl isocyanide monomers to give block copolymers. It was also found that incorporation of an electron-donating group on the phenyl group of the Pd complex could improve the catalytic activities. Furthermore, these Pd complexes were tolerant to most organic solvents and applicable to a wide range of isocyanide monomers including alkyl and phenyl isocyanides and even phenyl isocyanide with bulky substituents at the ortho position and diisocyanide monomers. Therefore, this polymerization system is versatile in the preparation of well-defined polyisocyanides with controlled sequence. Bi- and trifunctional Pd complexes with two and three Pd units incorporated onto the same phenyl ring were designed and synthesized. They were also able to initiate the living polymerization of phenyl isocyanide to afford telechelic linear and star-shaped polyisocyanides with controlled molecular weights and narrow molecular weight distributions.

A family of air-stable phenylethynyl palladium complexes was unexpectedly found to initiate the polymerization of phenyl isocyanide in a living/controlled chain growth manner, affording well-defined, stereoregular poly(phenyl isocyanide)s in high yield with controlled molecular weights and narrow molecular weight distributions.

A family of well-defined poly(3-hexylthiophene)-b-poly(5,8-di-p-tolylquinoxaline-2,3-diyl) rod–rod block copolymers was designed and synthesized in one pot via mechanistically distinct, sequential living polymerization using Ni(dppp)Cl2 as a single catalyst. The block copolymerization was demonstrated to proceed in a living/controlled chain-growth manner, affording the desired block copolymers in high yields with tunable compositions, controlled molecular weight, and narrow molecular weight distributions. The resulting block copolymer was revealed to self-assemble into various well-defined supramolecular structures depending on the solvents used such as nano-fibril and spherical nanoparticles. Very interestingly, such a block copolymer displayed highly selective visual detection for cobalt over most other competing metal ions by changing its orange color to light green and bright orange emission to deep green. The detection limit was estimated to be down to 1.0 × 10−7 M and the interference of the other competing metal ions is negligible. Furthermore, such a block copolymer can be applied using test strips, making it a practical, sensitive, and selective probe for cobalt ions.

Two allene derivatives, l- and d-N-(1-(octylamino)-1-oxopropan-2-yl)-4-(propa-1,2-dien-1-yloxy)benzamide (l-1 and d-1), bearing chiral amide pendants were designed and synthesized. Living polymerizations of l-1 and d-1 with allylnickel complex as a catalyst afforded poly-l-1m and poly-d-1m with controlled molecular weights and narrow molecular weight distributions. These polymers were found to possess a stable helical conformation with a preferred handedness in aprotic solvents on the basis of their circular dichroism (CD) spectra and specific rotation as well as computer simulation. The helical conformation of the polymers was revealed to be stabilized by elongation of the repeating unit until the degree of the polymerization reaches 80. The slightly influence of temperature on the CD spectra of poly-l-1100 in CHCl3 indicated the helical conformation was quite stable at least in the range of 0–55 °C. Although poly-l-1100 showed similar CD spectra in different aprotic solvents, remarkable decrease was observed upon the addition of protic solvents such as methanol due to the weakened hydrogen bonding interactions between the adjacent repeating units. The poly-l-1100 behaves as a pH-responsive property; the helical structure of the main chain can be transformed to random coil by addition of trifluoroacetic acid to the THF solution which again switches back to helical conformation by neutralization with triethylamine. It was confirmed that the copolymerization of l-1 and d-1 obeyed the majority rule as supported by the nonlinear correlation between the enantiomeric excess of monomer 1 with the CD intensities of the generated copolymers. Atomic force microscope (AFM) and scanning electron microscope (SEM) studies revealed poly-l-1100 self-assembled into well-defined helical fibrils with distinct handedness.

Simply prepared π-allylnickel complexes were used as external initiators for promoting the polymerization of 2-bromo-3-hexyl-5-chloromagnesiothiophene in a living/controlled chain growth manner to afford regioregular poly(3-hexylthiophene) with an allyl terminus. The nickel species on the other chain end can initiate the block copolymerization of hexadecyloxylallene and 2-bromo-3-hexyl-5-chloromagnesiothiophene to give a well-defined triblock copolymer containing poly(3-hexylthiophene) and poly(hexadecyloxylallene) segments in one pot via mechanically distinct, sequential living polymerization. Furthermore, such π-allylnickel(II) complexes can also catalyze the polymerization of a range of vinyl monomers, including styrene, 1-methoxy-4-vinylbenzene, and 1-chloro-4-vinylbenzene as well as tert-butyl acrylate, in living/controlled fashion. The active nickel unit at the growing chain end of these vinyl polymers can also initiate the block copolymerization of 2-bromo-3-hexyl-5-chloromagnesiothiophene to give a series of block copolymers containing vinyl polymer and poly(3-hexylthiophene) segments. The new block copolymerizations have been demonstrated to proceed in living/controlled chain-extension manner. The well-defined conjugated block copolymers are isolated in high yield with controlled molecular weight and tunable compositions.

A series of poly(3-hexylthiophene)-b-poly(hexadecyloxylallene) copolymers has been synthesized in one pot via sequential monomer addition by using Ni(dppp)Cl2 as a single catalyst. The copolymerization has been revealed to proceed by a controlled chain extension mechanism and the block copolymer can self-assemble into a well-defined supramolecular structure in solution and exhibit microphase separation in the solid state.

A range of poly(3-hexylthiophene)-b-poly(quinoxaline-2,3-diyl) rod–rod diblock copolymers was synthesized in one pot via sequential monomer addition with a Ni(II) complex as a single catalyst at room temperature. The block copolymerization was proved to proceed in a living/controlled chain-extension manner, affording well-defined poly(3-hexylthiophene)-b-poly(quinoxaline-2,3-diyl) block copolymers with controlled molecular weights, narrow molecular weight distributions, and tunable compositions. The synthesized block copolymer was found to self-assemble into well-defined vesicle supramolecular structures in mixed solvents of chloroform and methanol. The assembly in solution induced unique light emissions with the light emission color varying from red to purple and blue depending on solvents used.

A class of amphiphilic rod–rod diblock copolymers composed of hydrophilic π-conjugated poly(3-triethylene glycol thiophene) (P3(TEG)T) and hydrophobic rigid-rod-like poly(phenyl isocyanide) (PPI) was synthesized in one pot via mechanistically distinct, sequential block copolymerization with Ni(dppp)Cl2 as a single catalyst. The hydrophilic P3(TEG)T homopolymer self-assembled into well-defined nanoparticles in THF and methanol with different dimensions and exhibited orange-light emission in THF and red-light emission in methanol. Interestingly, the resultant P3(TEG)T-b-PPI block copolymers were found to self-assembled into various well-defined supramolecular structures, such as nanofibrils in THF, micelles in methanol, and vesicles in 3/2 mixtures of THF and methanol. The assemblies of these block copolymers in solutions exhibited unique light emissions with the emission color spanned widely from orange red to blue depending on self-assembled morphology and solvents used. White light emission can be readily achieved through the control of self-assembled morphologies by variation on the solvent composition. Moreover, the light emissions of the block copolymers were completely reversible, demonstrating the tunable emissions were indeed ascribed to the morphological transitions of the block copolymer.

A series of poly(3-hexylthiophene)-b-poly(hexadecyloxylallene) copolymers has been synthesized in one pot via sequential monomer addition by using Ni(dppp)Cl2 as a single catalyst. The copolymerization has been revealed to proceed by a controlled chain extension mechanism and the block copolymer can self-assemble into a well-defined supramolecular structure in solution and exhibit microphase separation in the solid state.