CO2 -Cross-Linked Frustrated Lewis Networks as Gas-Regulated Dynamic Covalent Materials

CO2 -Fueled Transient Breathing Nanogels that Couple Nonequilibrium Catalytic Polymerization

Here we present a "breathing" nanogel that is fueled by CO₂ gas to perform temporally programmable catalytic polymerization. The nanogel is composed of common frustrated Lewis pair polymers (FLPs). Dynamic CO₂ -FLP gas-bridging bonds endow the nanogel with a transient volume contraction, and the resulting proximal effect of bound FLPs unlocks its catalytic capacity toward CO₂ . Reverse gas depletion via a CO₂ -participated polymerization can induce a reverse nanogel expansion, which shuts down the catalytic activity. Control of external factors (fuel level, temperature or additives) can regulate the breathing period, amplitude and lifecycle, so as to affect the catalytic polymerization. Moreover, editing the nanogel breathing procedure can sequentially evoke the copolymerization of CO₂ with different epoxide monomers preloaded therein, which allows to obtain block-tunable copolycarbonates that are unachievable by other methods. This synthetic dissipative system would be function as a prototype of gas-driven nanosynthesizer.

What Fluorine Can Do in CO2 Chemistry: Applications from Homogeneous to Heterogeneous Systems

CO₂ chemistry including capture and fixation has attracted great attention towards the aim of reducing the consumption of fossil fuels and CO₂ accumulation in the atmosphere. "CO₂ -philic" materials are required to achieve good performance owing to the intrinsic properties of the CO₂ molecule, that is, thermodynamic stability and kinetic inertness. In this respect, fluorinated materials have been deployed in CO₂ capture (physical and chemical pathway) or fixation (thermo- and electrocatalytic procedure) with good performances, including homogeneous (e. g., ionic liquids and small organic molecules) and heterogeneous counterparts (e. g., carbons, porous organic polymers, covalent triazine frameworks, metal-organic frameworks, and membranes). In this Minireview, these works are summarized and analyzed from the aspects of (1) the strategy used for fluorine introduction, (2) characterization of the targeted materials, (3) performance of the fluorinated systems in CO₂ chemistry, and comparison with the nonfluorinated counterparts, (4) the role of fluorinated functionalities in the working procedure, and (5) the relationship between performance and structural/electronic properties of the materials. The systematic summary in this Minireview will open new opportunities in guiding the design of "CO₂ -philic" materials and pave the way to stimulate further progress in this field.

CO2 -Folded Single-Chain Nanoparticles as Recyclable, Improved Carboxylase Mimics

Emulating the function of natural carboxylases to convert CO₂ under atmospheric condition is a great challenge. Herein we report a class of CO₂ -folded single-chain nanoparticles (SCNPs) that can function as recyclable, function-intensified carboxylase mimics. Lewis pair polymers containing bulky Lewis acidic and basic groups as the precursor, can bind CO₂ to drive an intramolecular folding into SCNPs, in which CO₂ as the folded nodes can form gas-bridged bonds. Such bridging linkages highly activate CO₂ , which endows the SCNPs with extraordinary catalytic ability that can not only catalyze CO₂ -insertion of C(sp³ )-H for imitating the natural enzyme's function, it can also act on non-natural carboxylation pathways for C(sp² and sp)-H substrates. The nanocatalysts are of highly catalytic efficiency and recyclability, and can work at room temperature and near ambient CO₂ condition, inspiring a new approach to sustainable C₁ utilization.

Dynamic Bottlebrush Polymer Networks: Self-Healing in Super-Soft Materials

We introduce a design strategy to expand the range of accessible mechanical properties in covalent adaptable networks (CANs) using bottlebrush polymer building blocks. Well-defined bottlebrush polymers with rubbery poly(4-methylcaprolactone) side chains were cross-linked in formulations that include a bislactone and strong Lewis acid (tin ethylhexanoate). The resulting materials exhibit tunable stress-relaxation rates at elevated temperatures (160-180 °C) due to dynamic ester cross-links that undergo transesterification with residual hydroxy groups. Varying the cross-linker loading or bottlebrush backbone degree of polymerization yields predictable low-frequency shear moduli ca. 10-100 kPa, well below values typical of linear polymer CANs (1 MPa). These extensible networks can be stretched to strains as large as 350% before failure and undergo efficient self-healing to recover >85% of their original toughness upon repeated fracture and melt processing. In summary, molecular architecture creates new opportunities to tailor the mechanical properties of CANs in ways that are otherwise difficult to achieve.