Publications
233 results found
Yeo H, Gregory GL, Gao H, et al., 2024, Alternatives to fluorinated binders: recyclable copolyester/carbonate electrolytes for high-capacity solid composite cathodes., Chem Sci, Vol: 15, Pages: 2371-2379, ISSN: 2041-6520
Optimising the composite cathode for next-generation, safe solid-state batteries with inorganic solid electrolytes remains a key challenge towards commercialisation and cell performance. Tackling this issue requires the design of suitable polymer binders for electrode processability and long-term solid-solid interfacial stability. Here, block-polyester/carbonates are systematically designed as Li-ion conducting, high-voltage stable binders for cathode composites comprising of single-crystal LiNi0.8Mn0.1Co0.1O2 cathodes, Li6PS5Cl solid electrolyte and carbon nanofibres. Compared to traditional fluorinated polymer binders, improved discharge capacities (186 mA h g-1) and capacity retention (96.7% over 200 cycles) are achieved. The nature of the new binder electrolytes also enables its separation and complete recycling after use. ABA- and AB-polymeric architectures are compared where the A-blocks are mechanical modifiers, and the B-block facilitates Li-ion transport. This reveals that the conductivity and mechanical properties of the ABA-type are more suited for binder application. Further, catalysed switching between CO2/epoxide A-polycarbonate (PC) synthesis and B-poly(carbonate-r-ester) formation employing caprolactone (CL) and trimethylene carbonate (TMC) identifies an optimal molar mass (50 kg mol-1) and composition (wPC 0.35). This polymer electrolyte binder shows impressive oxidative stability (5.2 V), suitable ionic conductivity (2.2 × 10-4 S cm-1 at 60 °C), and compliant viscoelastic properties for fabrication into high-performance solid composite cathodes. This work presents an attractive route to optimising polymer binder properties using controlled polymerisation strategies combining cyclic monomer (CL, TMC) ring-opening polymerisation and epoxide/CO2 ring-opening copolymerisation. It should also prompt further examination of polycarbonate/ester-based materials with today's most relevant yet demanding high-voltage cathodes and sensitive sulfide-ba
Cowie BE, Mears KL, S'ari M, et al., 2024, Exploiting Organometallic Chemistry to Functionalize Small Cuprous Oxide Colloidal Nanocrystals., J Am Chem Soc, Vol: 146, Pages: 3816-3824
The ligand chemistry of colloidal semiconductor nanocrystals mediates their solubility, band gap, and surface facets. Here, selective organometallic chemistry is used to prepare small, colloidal cuprous oxide nanocrystals and to control their surface chemistry by decorating them with metal complexes. The strategy is demonstrated using small (3-6 nm) cuprous oxide (Cu2O) colloidal nanocrystals (NC), soluble in organic solvents. Organometallic complexes are coordinated by reacting the surface Cu-OH bonds with organometallic reagents, M(C6F5)2, M = Zn(II) and Co(II), at room temperature. These reactions do not disrupt the Cu2O crystallinity or nanoparticle size; rather, they allow for the selective coordination of a specific metal complex at the surface. Subsequently, the surface-coordinated organometallic complex is reacted with three different carboxylic acids to deliver Cu-O-Zn(O2CR') complexes. Selective nanocrystal surface functionalization is established using spectroscopy (IR, 19F NMR), thermal gravimetric analyses (TGA), transmission electron microscopy (TEM, EELS), and X-ray photoelectron spectroscopy (XPS). Photoluminescence efficiency increases dramatically upon organometallic surface functionalization relative to that of the parent Cu2O NC, with the effect being most pronounced for Zn(II) decoration. The nanocrystal surfaces are selectively functionalized by both organic ligands and well-defined organometallic complexes; this synthetic strategy may be applicable to many other metal oxides, hydroxides, and semiconductors. In the future, it should allow NC properties to be designed for applications including catalysis, sensing, electronics, and quantum technologies.
Shellard EJK, Diment WT, Resendiz-Lara DA, et al., 2024, Al(III)/K(I) Heterodinuclear Polymerization Catalysts Showing Fast Rates and High Selectivity for Polyester Polyols., ACS Catal, Vol: 14, Pages: 1363-1374, ISSN: 2155-5435
Low molar mass, hydroxyl end-capped polymers, often termed "polyols," are widely used to make polyurethanes, resins, and coatings and as surfactants in liquid formulations. Epoxide/anhydride ring-opening copolymerization (ROCOP) is a controlled polymerization route to make them, and its viability depends upon catalyst selection. In the catalysis, the polyester polyol molar masses and end-groups are controlled by adding specific but excess quantities of diols (vs catalyst), known as the chain transfer agent (CTA), to the polymerizations, but many of the best current catalysts are inhibited or even deactivated by alcohols. Herein, a series of air-stable Al(III)/K(I) heterodinuclear polymerization catalysts show rates and selectivity at the upper end of the field. They also show remarkable increases in activity, with good selectivity and control, as quantities of diol are increased from 10-400 equiv. The reactions are accelerated by alcohols, and simultaneously, their use allows for the production of hydroxy telechelic poly/oligoesters (400 < Mn (g mol-1) < 20,400, Đ < 1.19). For example, cyclohexene oxide (CHO)/phthalic anhydride (PA) ROCOP, using the best Al(III)/K(I) catalyst with 200 equiv of diol, shows a turnover frequency (TOF) of 1890 h-1, which is 4.4× higher than equivalent reactions without any diol (Catalyst/Diol/PA/CHO = 1:10-400:400:2000, 100 °C). In all cases, the catalysis is well controlled and highly ester linkage selective (ester linkages >99%) and operates effectively using bicyclic and/or biobased anhydrides with bicyclic or flexible alkylene epoxides. These catalysts are recommended for future production and application development using polyester polyols.
Vidal F, van der Marel ER, Kerr RWF, et al., 2024, Designing a circular carbon and plastics economy for a sustainable future., Nature, Vol: 626, Pages: 45-57
The linear production and consumption of plastics today is unsustainable. It creates large amounts of unnecessary and mismanaged waste, pollution and carbon dioxide emissions, undermining global climate targets and the Sustainable Development Goals. This Perspective provides an integrated technological, economic and legal view on how to deliver a circular carbon and plastics economy that minimizes carbon dioxide emissions. Different pathways that maximize recirculation of carbon (dioxide) between plastics waste and feedstocks are outlined, including mechanical, chemical and biological recycling, and those involving the use of biomass and carbon dioxide. Four future scenarios are described, only one of which achieves sufficient greenhouse gas savings in line with global climate targets. Such a bold system change requires 50% reduction in future plastic demand, complete phase-out of fossil-derived plastics, 95% recycling rates of retrievable plastics and use of renewable energy. It is hard to overstate the challenge of achieving this goal. We therefore present a roadmap outlining the scale and timing of the economic and legal interventions that could possibly support this. Assessing the service lifespan and recoverability of plastic products, along with considerations of sufficiency and smart design, can moreover provide design principles to guide future manufacturing, use and disposal of plastics.
Smith ML, McGuire TM, Buchard A, et al., 2023, Evaluating Heterodinuclear Mg(II)M(II) (M = Mn, Fe, Ni, Cu, and Zn) Catalysts for the Chemical Recycling of Poly(cyclohexene carbonate)., ACS Catal, Vol: 13, Pages: 15770-15778, ISSN: 2155-5435
Polymer chemical recycling to monomers (CRM) is important to help achieve a circular plastic economy, but the "rules" governing catalyst design for such processes remain unclear. Here, carbon dioxide-derived polycarbonates undergo CRM to produce epoxides and carbon dioxide. A series of dinuclear catalysts, Mg(II)M(II) where M(II) = Mg, Mn, Fe, Co, Ni, Cu, and Zn, are compared for poly(cyclohexene carbonate) depolymerizations. The recycling is conducted in the solid state, at 140 °C monitored using thermal gravimetric analyses, or performed at larger-scale using laboratory glassware. The most active catalysts are, in order of decreasing rate, Mg(II)Co(II), Mg(II)Ni(II), and Mg(II)Zn(II), with the highest activity reaching 8100 h-1 and with >99% selectivity for cyclohexene oxide. Both the activity and selectivity values are the highest yet reported in this field, and the catalysts operate at low loadings and moderate temperatures (from 1:300 to 1:5000, 140 °C). For the best heterodinuclear catalysts, the depolymerization kinetics and activation barriers are determined. The rates in both reverse depolymerization and forward CHO/CO2 polymerization catalysis show broadly similar trends, but the processes feature different intermediates; forward polymerization depends upon a metal-carbonate intermediate, while reverse depolymerization depends upon a metal-alkoxide intermediate. These dinuclear catalysts are attractive for the chemical recycling of carbon dioxide-derived plastics and should be prioritized for recycling of other oxygenated polymers and copolymers, including polyesters and polyethers. This work provides insights into the factors controlling depolymerization catalysis and steers future recycling catalyst design toward exploitation of lightweight and abundant s-block metals, such as Mg(II).
Hwang GB, Stent J, Noimark S, et al., 2023, White light-activated bactericidal coating using acrylic latex, crystal violet, and zinc oxide nanoparticles, Materials Advances, Vol: 5, Pages: 259-266
In this study, a white light-activated bactericidal coating consisting of acrylic latex, zinc oxide nanoparticles (ZnO NPs) and crystal violet (CV) was produced through a two-step dipping process. CV molecules and ZnO NPs were incorporated into an acrylic latex coating deposited onto a glass substrate. After the incorporation, the colour of the coating surface changed to purple from colourless and XPS sputtering analysis showed the existence of ZnO NPs within the coating. In a bactericidal test, the CV dyed samples showed an intrinsic bactericidal activity (0.7-0.88 log reduction in viable bacteria number) against S. aureus whereas it was not observed on E. coli in the dark. Upon white light irradiation (light intensity: 512 lux), the bactericidal activity of the CV-dyed sample was significantly enhanced. Compared to the control, the CV-dyed samples showed 1.16-2.51 log reduction against both bacterial strains in white light. In terms of the testing against S. aureus in white light, ZnO NPs addition into the CV-dyed sample showed enhanced bactericidal activity. The bactericidal activity of the CV-dyed sample with ZnO NPs was 1.34 log higher than the CV-dyed sample. Based on data obtained from TR-EPR spectroscopy, it is speculated that the addition of ZnO NPs into the dye induces an alternative photoredox pathway, resulting in more generation of reactive oxygen species lethal to bacterial cells. It is expected that this technique could be used to transform a wide range of surfaces into bactericidal surfaces and contribute to maintaining low pathogen levels on hospital surfaces related to healthcare-associated infection.
Lindeboom W, Deacy AC, Phanopoulos A, et al., 2023, Correlating metal redox potentials to Co(III)K(I) catalyst performances in carbon dioxide and propene oxide ring opening copolymerization, Angewandte Chemie International Edition, Vol: 62, ISSN: 1433-7851
Carbon dioxide copolymerization is a front-runner CO2 utilization strategy but its viability depends on improving the catalysis. So far, catalyst structure-performance correlations have not been straightforward, limiting the ability to predict how to improve both catalytic activity and selectivity. Here, a simple measure of a catalyst ground-state parameter, metal reduction potential, directly correlates with both polymerization activity and selectivity. It is applied to compare performances of 6 new heterodinuclear Co(III)K(I) catalysts for propene oxide (PO)/CO2 ring opening copolymerization (ROCOP) producing poly(propene carbonate) (PPC). The best catalyst shows an excellent turnover frequency of 389 h−1 and high PPC selectivity of >99 % (50 °C, 20 bar, 0.025 mol% catalyst). As demonstration of its utility, neither DFT calculations nor ligand Hammett parameter analyses are viable predictors. It is proposed that the cobalt redox potential informs upon the active site electron density with a more electron rich cobalt centre showing better performances. The method may be widely applicable and is recommended to guide future catalyst discovery for other (co)polymerizations and carbon dioxide utilizations.
McGuire TM, Buchard A, Williams C, 2023, Chemical Recycling of Commercial Poly(L-lactic acid) to L-Lactide Using a High-Performance Sn(II)/Alcohol Catalyst System, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 145, Pages: 19840-19848, ISSN: 0002-7863
Poon KC, Gregory GL, Sulley GS, et al., 2023, Toughening CO<sub>2</sub>-Derived Copolymer Elastomers Through Ionomer Networking, ADVANCED MATERIALS, Vol: 35, ISSN: 0935-9648
- Author Web Link
- Cite
- Citations: 1
Fiorentini F, Diment WTT, Deacy ACC, et al., 2023, Understanding catalytic synergy in dinuclear polymerization catalysts for sustainable polymers, NATURE COMMUNICATIONS, Vol: 14
- Author Web Link
- Cite
- Citations: 1
Cowie BE, Häfele L, Phanopoulos A, et al., 2023, Matched ligands for small, stable colloidal nanoparticles of copper, cuprous oxide and cuprous sulfide, Chemistry: A European Journal, Vol: 29, Pages: 1-18, ISSN: 0947-6539
This work applies organometallic routes to copper(0/I) nanoparticles and describes how to match ligand chemistries with different material compositions. The syntheses involve reacting an organo-copper precursor, mesitylcopper(I) [CuMes]z (z=4, 5), at low temperatures and in organic solvents, with hydrogen, air or hydrogen sulfide to deliver Cu, Cu2 O or Cu2 S nanoparticles. Use of sub-stoichiometric quantities of protonated ligand (pro-ligand; 0.1-0.2 equivalents vs. [CuMes]z ) allows saturation of surface coordination sites but avoids excess pro-ligand contaminating the nanoparticle solutions. The pro-ligands are nonanoic acid (HO2 CR1 ), 2-[2-(2-methoxyethoxy)ethoxy]acetic acid (HO2 CR2 ) or di(thio)nonanoic acid, (HS2 CR1 ), and are matched to the metallic, oxide or sulfide nanoparticles. Ligand exchange reactions reveal that copper(0) nanoparticles may be coordinated by carboxylate or di(thio)carboxylate ligands, but Cu2 O is preferentially coordinated by carboxylate ligands and Cu2 S by di(thio)carboxylate ligands. This work highlights the opportunities for organometallic routes to well-defined nanoparticles and the need for appropriate ligand selection.
Wilmore JTT, Tse YC, Docker A, et al., 2023, Dynamic Metalloporphyrin-Based [2]Rotaxane Molecular Shuttles Stimulated by Neutral Lewis Base and Anion Coordination, CHEMISTRY-A EUROPEAN JOURNAL, Vol: 29, ISSN: 0947-6539
Vidal F, Smith S, Williams CK, 2023, Ring Opening Copolymerization of Boron-Containing Anhydride with Epoxides as a Controlled Platform to Functional Polyesters, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 145, Pages: 13888-13900, ISSN: 0002-7863
- Author Web Link
- Cite
- Citations: 1
Diment WT, Rosetto G, Ezaz-Nikpay N, et al., 2023, A highly active, thermally robust iron(iii)/potassium(i) heterodinuclear catalyst for bio-derived epoxide/anhydride ring-opening copolymerizations, GREEN CHEMISTRY, Vol: 25, Pages: 2262-2267, ISSN: 1463-9262
- Author Web Link
- Cite
- Citations: 3
Gregory GL, Sulley GS, Kimpel J, et al., 2022, Block Poly(carbonate-ester) Ionomers as High-Performance and Recyclable Thermoplastic Elastomers, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Vol: 61, ISSN: 1433-7851
- Author Web Link
- Cite
- Citations: 10
Deacy AC, Phanopoulos A, Lindeboom W, et al., 2022, Insights into the mechanism of carbon dioxide and propylene oxide ring-opening copolymerization using a Co(III)/K(I) heterodinuclear catalyst, Journal of the American Chemical Society, Vol: 144, Pages: 17929-17938, ISSN: 0002-7863
A combined computational and experimental investigation into the catalytic cycle of carbon dioxide and propylene oxide ring-opening copolymerization is presented using a Co(III)K(I) heterodinuclear complex (Deacy, A. C. Co(III)/Alkali-Metal(I) Heterodinuclear Catalysts for the Ring-Opening Copolymerization of CO2 and Propylene Oxide. J. Am. Chem. Soc. 2020, 142(45), 19150−19160). The complex is a rare example of a dinuclear catalyst, which is active for the copolymerization of CO2 and propylene oxide, a large-scale commercial product. Understanding the mechanisms for both product and byproduct formation is essential for rational catalyst improvements, but there are very few other mechanistic studies using these monomers. The investigation suggests that cobalt serves both to activate propylene oxide and to stabilize the catalytic intermediates, while potassium provides a transient carbonate nucleophile that ring-opens the activated propylene oxide. Density functional theory (DFT) calculations indicate that reverse roles for the metals have inaccessibly high energy barriers and are unlikely to occur under experimental conditions. The rate-determining step is calculated as the ring opening of the propylene oxide (ΔGcalc† = +22.2 kcal mol–1); consistent with experimental measurements (ΔGexp† = +22.1 kcal mol–1, 50 °C). The calculated barrier to the selectivity limiting step, i.e., backbiting from the alkoxide intermediate to form propylene carbonate (ΔGcalc† = +21.4 kcal mol–1), is competitive with the barrier to epoxide ring opening (ΔGcalc† = +22.2 kcal mol–1) implicating an equilibrium between alkoxide and carbonate intermediates. This idea is tested experimentally and is controlled by carbon dioxide pressure or temperature to moderate selectivity. The catalytic mechanism, supported by theoretical and experimental investigations, should help to guide future catalyst design and optim
McGuire TM, Deacy AC, Buchard A, et al., 2022, Solid-State Chemical Recycling of Polycarbonates to Epoxides and Carbon Dioxide Using a Heterodinuclear Mg(II)Co(II) Catalyst, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, ISSN: 0002-7863
- Author Web Link
- Cite
- Citations: 12
Gregory GL, Gao H, Liu B, et al., 2022, Buffering Volume Change in Solid-State Battery Composite Cathodes with CO<sub>2</sub>-Derived Block Polycarbonate Ethers, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, ISSN: 0002-7863
- Author Web Link
- Cite
- Citations: 10
Diment WT, Lindeboom W, Fiorentini F, et al., 2022, Synergic Heterodinuclear Catalysts for the Ring-Opening Copolymerization (ROCOP) of Epoxides, Carbon Dioxide, and Anhydrides, ACCOUNTS OF CHEMICAL RESEARCH, Vol: 55, Pages: 1997-2010, ISSN: 0001-4842
- Author Web Link
- Cite
- Citations: 23
Diment WT, Williams CK, 2022, Chain end-group selectivity using an organometallic Al(iii)/K(i) ring-opening copolymerization catalyst delivers high molar mass, monodisperse polyesters, CHEMICAL SCIENCE, Vol: 13, Pages: 8543-8549, ISSN: 2041-6520
- Author Web Link
- Cite
- Citations: 6
Singer FN, Deacy AC, McGuire TM, et al., 2022, Chemical Recycling of Poly(Cyclohexene Carbonate) Using a Di-Mg<SUP>II</SUP> Catalyst, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Vol: 61, ISSN: 1433-7851
- Author Web Link
- Cite
- Citations: 24
Kerr RWF, Williams CK, 2022, Zr(IV) Catalyst for the Ring-Opening Copolymerization of Anhydrides (A) with Epoxides (B), Oxetane (B), and Tetrahydrofurans (C) to Make ABB- and/or ABC-Poly(ester-<i>alt</i>-ethers), JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 144, Pages: 6882-6893, ISSN: 0002-7863
- Author Web Link
- Cite
- Citations: 16
Gregory GL, Williams CK, 2022, Exploiting Sodium Coordination in Alternating Monomer Sequences to Toughen Degradable Block Polyester Thermoplastic Elastomers, MACROMOLECULES, Vol: 55, Pages: 2290-2299, ISSN: 0024-9297
- Author Web Link
- Cite
- Citations: 12
Reis N, Deacy AC, Rosetto G, et al., 2022, Heterodinuclear Mg(II)M(II) (M=Cr, Mn, Fe, Co, Ni, Cu and Zn) Complexes for the Ring Opening Copolymerization of Carbon Dioxide/Epoxide and Anhydride/Epoxide, CHEMISTRY-A EUROPEAN JOURNAL, Vol: 28, ISSN: 0947-6539
- Author Web Link
- Cite
- Citations: 19
Plajer AJ, Williams CK, 2022, Heterocycle/Heteroallene Ring-Opening Copolymerization: Selective Catalysis Delivering Alternating Copolymers, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Vol: 61, ISSN: 1433-7851
- Author Web Link
- Cite
- Citations: 60
Plajer AJ, Williams CK, 2021, Heterotrinuclear Ring Opening Copolymerization Catalysis: Structure-activity Relationships, ACS CATALYSIS, Vol: 11, Pages: 14819-14828, ISSN: 2155-5435
- Author Web Link
- Cite
- Citations: 16
Diment WT, Gregory GL, Kerr RWF, et al., 2021, Catalytic Synergy Using AI(III) and Group 1 Metals to Accelerate Epoxide and Anhydride Ring-Opening Copolymerizations, ACS CATALYSIS, Vol: 11, Pages: 12532-12542, ISSN: 2155-5435
- Author Web Link
- Cite
- Citations: 31
Rosetto G, Deacy AC, Williams CK, 2021, Mg(ii) heterodinuclear catalysts delivering carbon dioxide derived multi-block polymers, CHEMICAL SCIENCE, Vol: 12, Pages: 12315-12325, ISSN: 2041-6520
- Author Web Link
- Cite
- Citations: 22
Lindeboom W, Fraser DAX, Durr CB, et al., 2021, Heterodinuclear Zn(II), Mg(II) or Co(III) with Na(I) Catalysts for Carbon Dioxide and Cyclohexene Oxide Ring Opening Copolymerizations, CHEMISTRY-A EUROPEAN JOURNAL, Vol: 27, Pages: 12224-12231, ISSN: 0947-6539
- Author Web Link
- Cite
- Citations: 20
Said SA, Roberts CS, Lee JK, et al., 2021, Direct organometallic synthesis of carboxylate intercalated layered zinc hydroxides for fully exfoliated functional nanosheets, Advanced Functional Materials, Vol: 31, Pages: 1-11, ISSN: 1616-301X
Intercalation of organic anions into 2D materials can enable exfoliation, improve dispersion stability, increase surface area, and provide useful functional groups. In layered metal hydroxides, intercalation of bulk structures is commonly achieved by cumbersome and typically incomplete anion exchange reactions. In contrast, here, a series of carboxylate-intercalated layered zinc hydroxides (LZH-R) are synthesized directly, at room temperature, by reacting an organozinc reagent with a precise sub-stoichiometric quantity of the desired carboxylic acid and water. A range of carboxylic acids are used to make new LZH-R materials which are crystalline, soluble, and functionalized, as established by X-ray diffraction, spectroscopic, and microscopy techniques. When R is an alkyl ether carboxylate, this direct synthesis method results in the spontaneous exfoliation of the LZH-R into monolayer nanosheets with high yields (70–80%) and high solubilities in alcohols and water of up to 180 mg mL−1. By altering the carboxylate ligand, functional groups suitable for post-synthetic modification or for detection by fluorescence are also introduced. These examples demonstrate a versatile synthetic route for functional exfoliated nanosheets.
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.