Direct coordination-insertion copolymerization of ethylene with polar monomers provides an atom- and energy-efficient route to functionalized polyolefins. However, the incorporation of nitrogen-containing comonomers into polyolefins remains problematic due to nitrogen-induced catalyst poisoning. Herein, two highly strained bicyclic nitrogen-containing comonomers (aminooxy-embedded norbornene: NB NO , aza-embedded norbornene: NB NN ) are introduced, which effectively diminish the catalyst poisoning propensity. The copolymerization of ethylene with NB NO results in the formation of poly(E-NB NO ) with high comonomer incorporation of 38.3 mol %. Likewise, the reaction with NB NN produces poly(E-NB NN ), which possesses both high molecular weight of 108.1 x 103 g mol-1 and high comonomer incorporation of 28.3 mol %. By adjusting the concentration of NB NN , the semicrystalline poly(E-NB NN ) (T m = 126-127 degrees C) is transformed into the amorphous, transparent, optical poly(E-NB NN ) (T g = 60-132 degrees C; transmittance = 95.2-96.6% at 400 nm). Notably, poly(E-NB NO ) undergoes N-O reductive cleavage, giving bifunctional poly(E-NH-OH) that features both -OH and -NH moieties. Poly(E-NB NN ) is transformed into an azo-containing polyolefin [poly(E-N=N)]. Precise modulation of the N2-extrusion conditions in poly(E-N=N) enables the formation of diverse all-hydrocarbon cyclo-containing polyolefin architectures, which are difficult to access by other methods. This work circumvents conventional nitrogen-induced deactivation and provides a versatile platform for the synthesis and transformation of nitrogen-functionalized polyolefins.

In the rapidly evolving field of advanced materials science, the development of optical polymers with high refractive index has attracted much attention. Among these optical polymers, cyclic olefin polymers (COPs) have stood out as a versatile platform owing to exceptional transparency, low birefringence, good heat resistance, low moisture absorption, and superior chemical resistance. However, they suffer from a relatively low refractive index, ranging from n = 1.52 to 1.54, which poses a challenge. In this contribution, we demonstrate that the incorporation of aromatic groups into the polymer backbone has opened up new horizons, particularly in the pursuit of materials with high refractive index. COPs with high refractive index and high glass-transition temperature (Tg) are prepared via ring-opening metathesis polymerization (ROMP) and subsequent hydrogenation. Notably, these all-hydrocarbon COPs are amorphous, have a wide Tg range of 30-282 degrees C, exhibit high thermal stability (Td,5% = 414-471 degrees C), and possess significantly high refractive index (1.5815-1.6748 at 589 nm) and excellent optical transmittance (89.0%-95.3%), making them promising candidates for advanced optical applications.

Abstract High-refractive-index polymers (HRIPs) are critical materials for advanced optoelectronic devices and have long been sought after. Importantly, cycloolefin-containing polymers have emerged as promising candidates due to their exceptional optical properties and broad range of applications; however, accessing HRIPs based on cycloolefin architectures remains a considerable challenge. To synthesize HRIPs, aromatic rings, sulfur atoms, and halogens (except fluorine) are commonly employed. This perspective highlights recent advances in the design and synthesis of high-refractive-index cycloolefin-containing polymeric materials through various synthetic methods, including coordination polymerization, ring-opening metathesis polymerization, thiol–ene click reaction, inverse vulcanization, and nanohybridization with inorganic additives. It also gives an outlook on promising directions in developing novel HRIPs based on cycloolefin frameworks for versatile applications.

Cyclic olefin copolymer is one of the most promising optical materials, but suffers from the issue of relatively low refractive index. The incorporation of 1-olefin into the polymer chain markedly enhanced its flexibility and solubility, and the elongation at break showed a corresponding rise, although the tensile strength underwent a decrease. In this contribution, the flexible 1-octene as the third comonomer was introduced to conduct the terpolymerization with ethylene and cyclic olefins by using the zirconocene catalyst under the activation of methylaluminoxane. The microstructures of the resultant terpolymers were characterized, and the effect of the incorporated 1-octene was determined by analyzing the optical, thermal and mechanical properties of the ter- polymers. By introducing 1-octene, the glass transition temperatures (Tg) were lowered to the range of 63-184 degrees C, close to those (65-178 degrees C) of commercial materials. Moreover, these terpolymers exhibited high refractive indices (1.627-1.675 at 589 nm) and excellent optical transparency (up to 96 % at 400 nm). A high tensile strength of 52.0 MPa was achieved, along with a strain at break value of epsilon = 5.0 %. This strategy effectively reduced the Tg of cyclic olefin copolymers, promoting the possibility of processing at lower temperatures. More importantly, optical and mechanical properties were maintained. The developed terpolymers are particularly promising for applications in optical devices, such as high-performance lenses and advanced display technologies.

Despite polyethylene's (PE) inherent thermal stability, its mechanical performance deteriorates above 80 degrees C, leading to material failure in high-temperature applications or solvents. While commercial cross-linked polyethylene (XLPE) technologies-gamma-irradiation and peroxide-mediated cross-linking-address these issues partially, they suffer from uncontrolled network architectures, incomplete gelation, and performance compromises due to the introduction of additives or the formation of byproducts. Here, we report a benzocyclobutene (BCB)-based cross-linking strategy that eliminates the need for additives and the formation of byproducts while preserving PE's non-polar integrity. A norbornene-derived BCB monomer was rationally designed and incorporated into polyethylene via two pathways including ring-opening metathesis polymerization and coordination-insertion copolymerization. Thermal activation triggered a quantitative BCB [4 + 4] cycloaddition, achieving complete gelation and forming robust eight-membered ring networks. The cross-linked materials exhibited exceptional thermal stability, structural stability at high temperature, and intrinsic hydrophobicity. This methodology overcomes conventional challenges-residual catalysts and toxic byproducts-enabling the development of upgrading XLPE for potential applications. By combining molecular design with industrially viable thermal processing, this work establishes BCB chemistry as a platform for next-generation polyolefin thermosets.

High-refractive-index polymers are important optical materials in optoelectronics. Conventional cyclic olefin polymers (COPs), possessing many excellent optical properties, are a class of highly promising optical materials; however, one of the greatest obstacles is their low refractive index of n = 1.52-1.54. Here, one efficient strategy of first incorporating high molar refraction groups, including carbazolyl and indolyl moieties, into unsaturated COPs via ring-opening metathesis polymerization (ROMP) and then introducing another high molar refraction sulfur atom by a subsequent thiol-ene click reaction is presented. The obtained cross-linked COPs bearing both an aromatic group and sulfur possess significantly higher refractive indices (n = 1.611-1.684 at 589 nm) and highly optical transparency (approximately 95%) in the range of vis-NIR. This provides a way toward potential applications of new-generation optical materials.

High-refractive-index polymers are important materials in optoelectronics. Cyclic olefin copolymers (COCs) are among the most promising optical materials; however, high-refractive-index COCs still remain unsolved but are highly desired. In this study, principles for designing all-hydrocarbon high-refractive-index COCs were proposed. Diverse COCs were prepared by zirconium-catalyzed coordination-insertion copolymerization of nine types of aromatic group-containing cyclic olefins with ethylene. In all-hydrocarbon optical polymers, these COCs have significantly higher refractive indices of >1.60, >1.65, and >1.70 compared to the previous values at moderate cyclic olefin incorporation (maximum: 35.7 mol%) and are highly optically transparent (90%-94%) in the visible wavelength range. Furthermore, these COCs are amorphous, have a wide T-g range of 92-262degree celsius, exhibit high thermal stability (T-d,T-5% = 372-442 degrees C), and possess extremely low hygroscopicity of <0.01%. These merits of all-hydrocarbon COCs indicate their potential as optical materials.

Direct copolymerization of olefins with polar monomers to produce functionalized polyolefins has attracted much attention; however, highly efficient incorporation of amide functions into polyolefins is a long-standing challenge because the amide function is pronounced to retard chain growth. In this that contain high ring strain and an amide moiety are utilized in ethylene copolymerization mediated by palladium catalysts. Amidefunctionalized polyethylenes, poly(E-VLBoc)s, are accessible with key characteristics of high amide incorporations (up to 30.1 mol %), high copolymer molecular weights, and high catalytic activities. The incorporation of the amide comonomer converts crystalline poly(E-VLBoc)s (T-m = 115-125 degrees C) to noncrystalline and transparent poly(E-VLBoc)s (T-g = 98-196 degrees C, optical transmittance (T) = 87.6%-90.4%). Both characteristics of cyclic amide functions and high amide incorporations in poly(E-VLBoc) enable facile post-transformations under mild conditions to produce hydrogen bond-containing (-C(O)NH-) poly(E-VLH), difunctionalized (-COOH and -NHR) poly(E-VLNHBoc), and water-soluble ammonium-functionalized poly(E-VLNH3+). The ammonium functionality endows polyolefin with antibacterial properties.

Semiconductors biohybrids integrate the best of biological catalysts and semiconductor nanomaterials for solar-to-chemical conversion. To realize the potential of hybrid systems at the commercial level, it remains an urgent need for cost-competitive and environmentally friendly approaches to scaling up. Here, we successfully tackle this challenge through developing biohybrid route that co-utilize multi-pollutants in wastewater to produce semiconductor biohybrids in-situ for solar-to-chemical production. To achieve cost-effective biohybrid production, we introduced an aerobic sulfate reduction pathway into Vibrio natriegens to enable the direct utilization of the heavy metal ions ( i . e ., Cd 2+ ), sulfate, and organics in the wastewater to biosynthesize functional semiconductor nanoparticles in living V. natriegens . Furthermore, 2,3-butanediol biosynthetic pathway was introduced into the V. natriegens hybrid to couple the solar energy for enhanced bioproduction. We demonstrated the scalability of this system in a 5-L illuminated fermenter using wastewater as the feedstock, which resulted in production of 13 g/L of 2,3-butanediol. Life cycle analysis showed this specific biohybrid route had a significantly lower cost and reduced CO 2 emission compared to both pure sugars fermentation and fossil-based routes. In addition to providing a promising step toward sustainable commercializing semiconductor biohybrids for biomanufacturing, our work may lead to hybrid living matter toward future waste to wealth conversion.

Cyclic olefin copolymer (COC) is one of the most promising optical materials; however, the brittle COC suffers from issues including a low refractive index. In this contribution, by the introduction of high refractive index comonomers including phenoxy substituted α-olefin (C4OAr), p-tolylthio substituted α-olefin (C4SAr) and carbazolyl substituted α-olefins (C4NAr, C3NAr, and C2NAr), the zirconocene mediated terpolymerization of ethylene (E) and tetracyclododecene (TCD) produces the preferred E-TCD-CnNAr (n = 2, 3, and 4) cyclic olefin terpolymers (COT) with tunable compositions (TCD: 11.5- 35.8 mol %, CnNAr: 1.2-5.0 mol %), high molecular weights and high glass transition temperatures (up to 167 °C) in high catalytic activities. Compared to the E-TCD copolymer (COC) material, these COT materials show the comparable thermal decomposition temperature (Td,5% = 437 °C), slightly higher strain at break value (up to 7.4%) and higher tensile strength (up to 60.5 MPa). In particular, these noncrystalline optical COT materials have significantly higher refractive indices of 1.550-1.569 and are more transparent (transmittance: 93-95%), relative to the COC materials, indicative of an excellent optical material.

Semiconductor biohybrids integrating the merits of living cells and semiconductor materials have the potential to shift the current energy-intensive chemical production system to a more sustainable one by offering efficient solar-to-chemical conversion. However, cost-competitive and environmentally friendly scaling-up approaches are still urgently needed. To tackle this challenge, we propose a strategy that co-utilizes pollutants in wastewater to produce semiconductor biohybrids in - situ for scalable solar-to-chemical conversion. Specifically, we introduce an aerobic sulfate reduction pathway into Vibrio natriegens to enable the direct utilization of heavy metal ions (that is, Cd 2+ ), sulfate and organics in wastewater to biosynthesize functional semiconductor nanoparticles in living V. natriegens to assemble semiconductor biohybrids. Meanwhile, a designated biosynthetic pathway is introduced into the biohybrids to enable the production of 2,3-butanediol, a valuable bulk chemical with wide applications, from organics in wastewater. Using the obtained biohybrids, the production of 2,3-butanediol reaches 13.09 g l −1 in a 5-l illuminated fermenter using wastewater as the feedstock, revealing its scalability. Life-cycle assessment shows that this specific biohybrid route has substantial sustainability gain compared with conventional 2,3-butanediol production routes. This work can bring solar-driven biomanufacturing and waste-to-wealth conversion one step forward and pave the way to cleaner production and circular economy.

To address the issue of hemilabile catalyst in olefin polymerization catalysis, a cyclizing strategy was used to construct novel N-bridged phosphine-carbonyl palladium and nickel catalysts, resulting in improvements on ethylene (co)polymerizations. The N-bridged phosphine-carbonyl Pd catalysts (Pd1−Pd5) and Ni catalysts (Ni1−Ni5) bearing five- to eight-membered-ring structures were designed and synthesized. Catalytic performance for ethylene (co)polymerization became better as the size of N-containing bridge increased. The seven-membered-ring bridged catalysts Pd4 and Ni4 exhibited the best performance in terms of catalytic activity, polymer molecular weight and incorporation of acrylates and acrylic acid. The better performance of these catalysts bearing larger-size bridges was tentatively attributed to the methylene-induced higher electron density around nitrogen, which strenghtens the coordination of carbonyl group to metal center, and also to the steric effect offered by this cyclization. This work provides a new strategy to enhance hemilabile polymerization catalysts.

The rise of inorganic-biohybrid organisms for solarto-chemical production has spurred mechanistic investigations into the dynamics of the biotic-abiotic interface to drive the development of next-generation hybrid systems. The model system, cyanobacteria-gold nanoparticle hybrids, combines a light harvester with a photosynthetic bacterium to drive the reduction of CO2 to glycerol with improved efficiency and increased glycerol production by 14.6%, in comparison to cyanobacteria only. In this work, we report insights into this unique photochemical behavior and propose a charge-transfer pathway from Au nanoparticle to cyanobacteria. Transient absorption (TA) spectroscopy revealed that photoexcited electron transfer rates are on the order of a few ps to the potential electron acceptor in photosystem II. This work represents a promising platform to utilize a conventional spectroscopic methodology to extract insights from more complex biotic-abiotic hybrid systems.

Compared with steric bulk and electronic effect in transition metal catalysts for olefin coordination-insertion polymerization, fluorine effect is one facile and effective method for modulating olefin polymerization reaction. However, study on fluorine effect in late transition metal catalysts is relatively less. In this contribution, by installation of fluorine atoms with different sites and numbers into N,O-type single-component cationic a-ketiminato nickel catalysts, fluorine effect on ethylene polymerization properties was comprehensively investigated, including catalytic activity, thermal stability of catalyst, polymer molecular weight, and branching density. These new nickel catalysts were fully identified by H-1-NMR and C-13-NMR spectroscopy, elemental analysis, and X-ray diffraction analysis. It was fully found that the ortho-fluorinated substituent in the nickel catalyst obviously favoured the enhancement of polymer molecular weight (weight-average molecular weight (M-w): up to 26.2x10(4) g.mol(-1)), but the meta- and para-fluorinated substituents in the nickel catalysts reduced the catalytic activity; especially the perfluorinated substituent in the nickel catalyst not only decreased the thermal stability of catalyst, but also led to the drop of activity and molecular weight. It was completely different from the previously reported effect of fluorine on these catalytic systems such as fluorinated phenoxy-imine nickel and titanium catalysts. Notably, the non-fluorinated nickel catalyst was inactive for the copolymerization of ethylene and methyl acrylate (MA), but the ortho-fluorinated nickel catalyst showed activity and enabled the incorporation of comonomer (0.9 mol%), albeit with low activity. However, the ortho-fluorinated nickel catalyst was also inactive for other more challenging monomers such as methyl methacrylate (MMA), acrylic acid (AA), vinyl acetate (VA) and n-butyl vinyl ether (BVE). As expected, the long chain polar monomers such as 6-chlorohex-1-ene, methyl 10-undecenoate (UA), undecenoic acid (UCOOH) and 10-undecen-1-ol (UGH) exhibited better copolymerization behaviors using the ortho-fluorinated nickel catalyst. This work will help the community to understand the crucial role of fluorine effect in olefin polymerization.

The functionalization of polyolefins through the copolymerization of olefins and polar monomers catalyzed by late transition metals such as nickel and palladium is of academic and industrial significance. In recent years, a variety of versatile catalysts used in these copolymerization reactions have been summarized in many key reviews; however, the indispensable role of polar monomers in these copolymerizations has not been given due attention. In this review, the functions of custom-made polar monomers in these reactions including regulating polymerization via new mechanisms, generating novel polymer architectures, benefiting polymer post-modification, endowing polyolefins with specific properties, and introducing bifunctional groups into polyolefins are comprehensively discussed. The aim is to provide fresh viewpoints from the perspective of polar monomers rather than catalysts as usual.

N-Bridged phosphine–carbonyl Pd(ii) and Ni(ii) catalysts enable the enhancement of molecular weights in ethylene polymerization and copolymerization with polar comonomers.

Polymerization of polar styrene monomers and their copolymerization with ethylene are of great interest in both academia and industry. In comparison with hundreds of literature reports on palladium catalyzed (co)polymerization using polar vinyl monomers, studies on palladium catalyzed (co)polymerization using polar styrene monomers have received much less attention and remains almost unexplored. In this contribution, by employing the benchmark cationic alpha-diimine and neutral phosphine-sulfonate palladium catalysts 1 and 2, a comprehensive picture on (co)polymerization of polar styrene monomers including o-F, o-Cl, o-MeO, o-CN, o-OH, o-COOH, o-CHO, o-NO2, o-NH2, o-NMe2, o-PPh2, m-F, m-MeO, p-F, p-MeO, p-vinyl, and 2,3,4,5,6-F-5 functional groups was built. By utilizing the cationic catalyst 1, due to the formation of the cationic pi-eta(3)-benzyl chelate, homopolymerization of polar styrene monomers and the copolymerization with ethylene only generated atactic polar styrene homopolymers or produced no polymer, depending on the type of polar styrene monomers. In contrast, by using the neutral catalyst 2, homopolymerization of polar styrene monomers was not possible, but copolymerization with ethylene showed good activities (up to 290 kg mol(-1) h(-1)) to afford a family of new ethylene/polar styrene copolymers with high incorporations (up to 6.3 mol %). Interestingly, the incorporated comonomer units are prone to an average distribution at the saturated chain end, in-chain, and unsaturated chain end. The origin of this unexpected observation was explored through stoichiometric insertion studies using selected polar styrene comonomers.

Motivated by the need for a new generation of a-diimine Ni(II) and Pd(II) catalysts for tuning the catalytic activity, polymer molecular weight, comonomer incorporation, and branching density in ethylene polymerization and copolymerization with polar monomers, a family of a-diimine Ni(II) and Pd(II) catalysts Ipty-Ni1-4 and Ipty-Pd1-4 derived from sterically demanding and rotationally restricted pentiptycenyl N-aryl substituents were synthesized and fully characterized by NMR, IR, MALDI-TOF, elemental analysis, and X-ray diffraction. Pentiptycenyl-substituted Ni(II) and Pd(II) catalysts were further probed in ethylene (co)polymerization as a comparison with the rotationally free dibenzhydryl substituent reported previously. In the Ni-catalyzed ethylene polymerization (20-80 degrees C), catalytic activities ((0.64-3.74) x 10(6) g mol(-1) h(-1)), polymer molecular weights ((1.1-37.7) x 10(4) g mol(-1)), branching densities (6-55/1000C), and melting points (94-135 degrees C) could be tuned over a broad range. In the Pd-catalyzed ethylene polymerization, these catalysts gave varied catalytic activities ((1.4-54.7) x 10(4) g mol(-1) h(-1)) and polymer molecular weights ((0.8-39.6) x 10(4) g mol(-1)), but similar branching densities (62-72/1000C). Furthermore, these palladium catalysts exhibited a high MA incorporation of 1.0-4.1 mol % in the copolymerization of ethylene and methyl acrylate (MA). On the basis of these results, comparisons of the pentiptycenyl-derived and the dibenzhydryl-derived a-diimine Ni(II) and Pd(II) catalysts on ethylene (co)polymerization were made in detail.

Polycyanurates with excellent thermal, mechanical, and dielectric properties were derived from 4,4′-biscyanato-2,2′-trifluoromethylbiphenyl, and their properties were systematically compared with those of polycyanurates derived from bisphenol A dicyanate.

Chain-end-functionalization of (highly) branched ethylene oligomers was achieved in situ with the most/least bulky α-diimine nickel catalysts for the first time.