Metal Chelating Polymer Thin Films by Surface-Initiated ROMP and Modification
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Polymer Tacticity Effects in Polymer–Lanthanide Chelation Thermodynamics
Metal-chelating polymers are critical components in numerous applications. However, despite the known influence of polymer tacticity on both bulk and solution properties, most materials used in metal-chelation applications are atactic. Here, we investigate the relationship between polymer tacticity and polymer–lanthanide interactions in aqueous solution. We synthesized a series of five poly(methacrylic acid)s with systematic variations in tacticity (20–99% m diads) and used isothermal titration calorimetry to measure the thermodynamics of lanthanide binding to each material (ΔH, ΔG, ΔS, K a , and stoichiometry). We observed enthalpy–entropy compensation across this tacticity series, finding that both |ΔH| and |ΔS| decreased with decreasing m diad content while ΔG remained similar. Molecular dynamics simulations of the polymer–metal interactions revealed that the observed differences in binding thermodynamics may be largely ascribed to differences in polymer flexibility. Furthermore, these combined experimental and computational results demonstrate that metal binding can be influenced by altering the polymer stereochemistry, ultimately influencing the design of more efficient metal-chelating materials.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Photocatalysts Based on Cobalt-Chelating Conjugated Polymers for Hydrogen Evolution from Water
Developing photocatalytic systems for water splitting to generate oxygen and hydrogen is one of the biggest chemical challenges in solar energy utilization. In this work, we report the first example of heterogeneous photocatalysts for hydrogen evolution based on in-chain cobalt-chelating conjugated polymers. Four conjugated polymers chelated with earth abundant cobalt ions were synthesized and found to evolve hydrogen photocatalytically from water. These polymers are designed to combine functions of the conjugated backbone as light-harvesting antenna and electron transfer conduit with the in-chain bipyridyl chelated transition metal centers as catalytic active sites. In addition, these polymers are soluble in organic solvents, enabling effective interactions with the substrates as well as detailed characterization. We also found a polymer-dependent optimal cobalt chelating concentration at which the highest photocatalytic hydrogen production (PHP) activity can be achieved.
Li, Lianwei↗
Synthetic, structural, and luminescence study of uranyl coordination polymers containing chelating terpyridine and trispyridyltriazine ligands
In this work, seven uranyl coordination polymers [(UO 2 )(BrC 8 H 3 O 4 )(C 15 H 11 N 3 )] ( 1 ), [(UO 2 )(ClC 8 H 3 O 4 )(C 15 H 11 N 3 )] ( 2 ), [(UO 2 )(BrC 8 H 3 O 4 )(C 18 H 12 N 6 )]·H 2 O ( 3 ), [(UO 2 )(ClC 8 H 3 O 4 )(C 18 H 12 N 6 )]·2H 2 O ( 4 ), [(UO 2 )(C 8 H 3 IO 4 )(C 18 H 12 N 6 )]·2C 3 H 7 O ( 5 ), [(UO 2 )(C 9 H 6 O 4 )(C 18 H 12 N 6 )]·H 2 O ( 6 ), and [(UO 2 )(C 6 H 2 O 4 S)(C 18 H 12 N 6 )]·2H 2 O ( 7 ) containing N-donor ligands 2,2':6',2''-terpyridine (TPY) and 2,4,6-tripyridyl s-triazine (TPTZ); and O-donor linkers thiophene 2,5-dicarboxylic acid (TDC) and X-1,4-benzene dicarboxylic acid (X-BDC, where X = Me, Cl, Br, I) were synthesized and characterized using single crystal X-ray diffraction (SC-XRD), powder X-ray diffraction (PXRD), and fluorescence spectroscopy. Each compound crystallizes as binuclear pseudo dimers containing a UO 2 2+ pentagonal bipyramidal primary building unit. Fluorescence spectra of 1–4 , and 6–7 show characteristic UO 2 2+ emission whereas 5 is non-emissive. Red shifts within the emission of 1–4 are noted as a function of N-donor ligands TPY and TPTZ whereas emission shifts are not observed in TPTZ bearing compounds ( 3 , 4 , 6 , 7 ) containing different O-donor linkers. Luminescent lifetimes of 1–7 were obtained and fitted with either bi-exponential or tri-exponential components.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Design of a Symbiotic Device to Harvest Uranium from Seawater through the use of Shell Enclosures
At the current consumption rate, the global conventional reserves of uranium, 7.6 million tonnes, could be depleted in a little over a century. As reserves decrease, future uranium is expected to come from lower quality sites, resulting in higher extraction costs and even greater environmental impact. Fortunately, uranium is present in the ocean as uranyl ions at low concentrations of 3 ppb, which, over the total volume of the oceans, amounts to approximately 4.5 billion tonnes of uranium, nearly a thousand times that of conventional reserves. Methods to extract uranium from seawater have been studied since the early 1960's, when, at a time when uranium production was uncertain, post-World War II Britain desired a secure uranium supply. A recent review of uranium recovery technologies by found that uranium adsorbent by chelating polymers was the most promising in terms of adsorbent capacity, environmental footprint, and cost. In this technology, chelating polymers are deployed in seawater and remain submerged until the amount of captured uranium approaches the adsorption capacity. Then, an elution bath is used to strip metal ions, such as uranium, off the adsorbent polymer. A polymer may be immersed in a number of elution baths before it is regenerated by an alkali wash to free its functional groups, allowing for the reuse of the polymer. The output from the elution process undergoes purification and precipitation typical for mined uranium to produce yellowcake. Offshore systems for the extraction of uranium from seawater have been developed since the early 2000's. In these systems, the adsorbent is deployed and moored for extended periods of time, brought back to shore for the elution process, and redeployed afterward. The first system, developed by, used non-woven adsorbents that were immersed for 30 days in seawater. Due to the low mechanical strength of these fibers, they had to be incorporated into stacks composed of spacer nets and holders placed on large, heavy, floating frames, which resulted in a design that was too costly for implementation. More recently, buoyant braided adsorbents have been studied as a way to decrease the weight and cost of the system. In these systems, continuous polyethylene fibers are braided around a porous polypropylene float that can be made into long lengths. However, because this deployment scheme requires the adsorbent be brought back to shore for the elution process and redeployed afterward, this stand-alone, intermittent operation system has significant practical and economic deployment challenges and to date none of these systems have become economically viable. Detailed economic analysis by found that a major cost driver of seawater uranium extraction is the mooring and recovery of the adsorbent. Based on these results, first developed the development of a system that is attached to an offshore wind turbine and continuously takes the adsorbent from the ocean through an elution process and then returns it to the ocean. More recent designs by further build upon this idea. The integration of the design of a uranium harvesting system into an offshore wind turbine tower is pursued because the development of offshore wind or uranium harvesting by themselves bears a high capital cost for the structures, but if the mooring function can be shared, the overall cost for each will be lower. Furthermore, initial design analysis and prototyping of these symbiotic systems has proven they are technical feasible. (authors)
07 ISOTOPE AND RADIATION SOURCES↗
Cost Analysis of Wind and Uranium from Seawater Acquisition symbiotic Infrastructure using Shell Enclosures
At current consumption rates, global conventional reserves of uranium, estimated to be 7.6 million tonnes, could be depleted in a little over a century. As these reserves decrease, extraction of uranium is expected to shift to lower quality sites, resulting in higher extraction costs and greater environmental impact. Fortunately, the ocean contains approximately 4.5 billion tonnes of uranium, as uranyl ions at low concentrations of about 3 ppb. Uranium from seawater is a widely studied topic due to the long term security it can assure the nuclear fuel cycle. Additionally, harvesting uranium from seawater could reduce some of the environmental impacts associated with the recovery of land-based uranium. Seawater uranium is meant to create a cost ceiling that provides economic stability and potential savings, not to act as a direct competitor to terrestrial uranium. A recent review of uranium recovery technologies by found uranium adsorption by chelating polymers to be the most promising in terms of adsorbent capacity, environmental footprint, and cost. In this technology, chelating polymers are deployed in seawater and remain submerged until the amount of captured uranium approaches the adsorption capacity. Then, an elution bath is used to strip metal ions, such as uranium, off the adsorbent polymer. A polymer may be immersed in a number of elution baths before it is regenerated by an alkali wash to free its functional groups, allowing for the reuse of the polymer. The output from the elution process undergoes purification and precipitation typical for mined uranium to produce yellowcake. Offshore systems for the extraction of uranium from seawater have been developed since the early 2000's. The system currently studied by a nationwide consortium of national laboratory and university partners utilizes continuous adsorbent polyethylene fibers that are braided around a porous polypropylene float which can be made into long lengths. However, because this deployment scheme requires the adsorbent be brought to a mother-ship for the elution process and redeployed afterward, it has significant practical and economic deployment challenges. Detailed economic analysis have identified the adsorbent production and mooring as the most expensive components of the recovery process. Based on these results, proposed an alternative deployment method that is attached to an offshore wind turbine and continuously takes the adsorbent, that is fabricated into a belt, from the ocean through an elution process and before submerging it back into the sea. However, it has been found that adsorbents with high tensile strength and durability often have very low uranium adsorption properties. Hence, the Wind and Uranium from Seawater Acquisition symbiotic Infrastructure (WUSABI) previously studied, which requires the adsorbent into a belt held in tension, could face difficulties in an ocean environment. Instead, the design, further referred to in this paper as WUSABI-Koosh, utilized a two-part system to decouple the mechanical and chemical needs of an adsorbent for seawater harvesting of uranium. In these designs, the uranium adsorbent material with high adsorbent capacity is enclosed in a hard permeable outer shell with sufficient mechanical strength and durability for use in an offshore environment and chemical resilience against elution treatments. The integration of the design of a uranium harvesting system into an offshore wind turbine tower is pursued because the development of offshore wind or uranium harvesting by themselves bears a high capital cost for the structures, but if the mooring function can be shared, the overall cost for each will be lower. Furthermore, initial design analysis and prototyping of these symbiotic systems has proven they are technically feasible. This paper presents preliminary cost analysis for comparison to uranium recovery via alternative deployment schemes.
07 ISOTOPE AND RADIATION SOURCES↗
Structure–Function Relationships in Sequence-Controlled Copolymers for Rare Earth Element Chelation
The ability to tune material function through primary sequence is a defining feature of biological macromolecules, allowing precise control over structure and target interactions in complex aqueous environments. However, translating sequence–structure–function relationships to synthetic macromolecules is challenging due to their dispersity in sequence, conformation, and composition. Here, we report systematic studies of amphiphilic polymer chelators designed to probe how composition and patterning influence binding affinity and selectivity for rare earth elements (REEs), a series of technologically relevant metals with challenging separation profiles. A library of copolymers varying hydrophobic monomer composition and patterning was synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization, spanning statistical, gradient, and block architectures. REE binding was quantified using a high-throughput colorimetric assay, and reconstruction of polymer ensembles using kinetic stochastic simulations enabled quantitative comparisons of sequence heterogeneity, linking local monomer colocalization to emergent REE binding. Further, we investigated the role of different hydrophobic comonomers in tuning metal coordination, with binding trends linked to structural features that influence binding site desolvation. Complementary dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) measurements showed that both polymer and monomer architecture modulate metal-induced conformational changes, and that multichain assembly behavior emerges beyond critical hydrophobic thresholds. Sequence control also altered REE selectivity, with nonmonotonic differences observed across compositionally identical polymers with different sequence architectures. Together, these findings establish design principles that connect polymer sequence and structure to binding performance, guiding the design of macromolecular chelators with enhanced affinity and selectivity for applications in separations, sensing, and catalysis.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
A Facile Aqueous Solution Route for the Growth of Chalcogenide Perovskite BaZrS 3 Films
The prototypical chalcogenide perovskite, BaZrS 3 (BZS), with its direct bandgap of 1.7–1.8 eV, high chemical stability, and strong light–matter interactions, has garnered significant interest over the past few years. So far, attempts to grow BaZrS 3 films have been limited mainly to physical vapor deposition techniques. Here, we report the fabrication of BZS thin films via a facile aqueous solution route of polymer-assisted deposition (PAD), where the polymer-chelated cation precursor films were sulfurized in a mixed CS 2 and Ar atmosphere. The formation of a single-phase polycrystalline BZS thin film at a processing temperature of 900 °C was confirmed by X-ray diffraction and Raman spectroscopy. The stoichiometry of the films was verified by Rutherford Backscattering spectrometry and energy-dispersive X-ray spectroscopy. The BZS films showed a photoluminescence peak at around 1.8 eV and exhibited a photogenerated current under light illumination at a wavelength of 530 nm. Temperature-dependent resistivity analysis revealed that the conduction of BaZrS 3 films under the dark condition could be described by the Efros–Shklovskii variable range hopping model in the temperature range of 60–300 K, with an activation energy of about 44 meV.
36 MATERIALS SCIENCE↗
Misfit p-type transparent conductive oxide (TCO) films, methods and applications
A p-type transparent conductive oxide (TCO) mixed metal oxide material layer formed upon a substrate has a formula M1xM2yOz generally, CaxCoyOz more specifically, and Ca3Co4O9 most specifically. Embodiments provide that the p-type TCO mixed metal oxide material may be formed absent an epitaxial crystalline relationship with respect to the substrate while using a sol-gel synthesis method that uses a chelating polymer material and not a block copolymer material.
36 MATERIALS SCIENCE↗
Efficient conversion of lignin into a water-soluble polymer by a chelator-mediated Fenton reaction: optimization of H 2 O 2 use and performance as a dispersant
Transforming lignin into a water-soluble polymer.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
pH‐Responsive Relaxometric Behaviour of Coordination Polymer Nanoparticles Made of a Stable Macrocyclic Gadolinium Chelate
Abstract Lanthanide‐containing nanoscale particles have been widely explored for various biomedical purposes, however, they are often prone to metal leaching. Here we have created a new coordination polymer (CP) by applying, for the first time, a stable Gd III chelate as building block in order to prevent any fortuitous release of free lanthanide(III) ion. The use of the Gd‐DOTA‐4AmP complex as a design element in the CP allows not only for enhanced relaxometric properties (maximum r 1 =16.4 m m −1 s −1 at 10 MHz), but also for a pH responsiveness (Δ r 1 =108 % between pH 4 and 6.5), beyond the values obtained for the low molecular weight Gd‐DOTA‐4AmP itself. The CP can be miniaturised to the nanoscale to form colloids that are stable in physiological saline solution and in cell culture media and does not show cytotoxicity.
Aríñez‐Soriano, Javier↗
Ion Coordination and Chelation in a Glycolated Polymer Semiconductor: Molecular Dynamics and X-ray Fluorescence Study
Abstract not provided
Matta, Micaela↗
Luminescence of a Polymer Composite Doped with Boron Chelates. Mechanism of Luminescence Sensitization
It has been revealed that a sensitized luminescence of AntAcBF{sub 2} is observed in the boron difluoride dibenzoylmethanate (DBMBF{sub 2})–boron difluoride anthracenoylacetonate (AntAcBF{sub 2}) system in the polystyrene matrix. The emission mechanism of energy transfer from DBMBF{sub 2} to AntAcBF{sub 2} has been established. The luminescence properties of bilayer films with one layer containing DBMBF{sub 2} and another one containing AntAcBF{sub 2} have been investigated. At luminophore contents in equimolar quantities, one observes a white luminescence of the bilayer polymer composite.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Thermodynamic origins of the solvent-dependent stability of lithium polysulfides from first principles
An understanding of the complex solution phase chemistry of dissolved lithium polysulfides is critical to approaches aimed at improving the cyclability and commercial viability of lithium sulfur batteries. Experimental measurements are frustrated by the versatile sulfur–sulfur bond, with spontaneous disproportionation and interconversion leading to unknown equilibrium distributions of polysulfides with varying lengths and charge states. The solubility of isolated lithium polysulfides is calculated from first-principles molecular dynamics simulations. We explore the associated changes in the dissolution free energy, enthalpy and entropy in two regimes: liquid-phase monodentate solvation in dimethylformamide (DMF) and polymer-like chelation in bis(2-methoxyethyl) ether (diglyme). In both of these technologically relevant solvents, we show that the competition between enthalpy and entropy, related to specific interfacial atomic interactions, conspires to increase the relative stability of long chain dianionic species, which exist as Li + –LiS x - contact-ion-pairs. Further, we propose a mechanism of radical polysulfide stabilization in simple solvents through the reorientation of the 1 st shell solvent molecules to screen electrostatic fields emanating from the solute and explain nonmonotonicity of the dissolution entropy with polysulfide length in terms of a three-shell solvation model. Finally, our analysis provides statistical dynamics insights into polylsulfide stability, useful to understand or predict the relevant chemical species present in the solvent at low concentrations.
36 MATERIALS SCIENCE↗
Local Chain Dynamics in Sequence-Controlled Polymers as a Tunable Handle for Rare Earth Sequestration
Chain dynamics govern the intricate behaviors of proteins, underpinning functions such as catalysis, recognition, and stimulus response, and are an increasingly appreciated aspect of structure–function relationships. Analogously, manipulating chain dynamics and structure in abiotic polymers via sequence control is an exciting, yet underexplored, strategy for improving material functions. In this work, we report a systematic study relating the sequence of polymeric sequestrants to their structure and dynamics, as well as to their binding affinity and selectivity for model substrates, rare earth elements (REEs). A series of sequence-controlled polymers with metal chelating, solubilizing, and structure forming monomers was synthesized via multiblock polymerization, yielding compositionally identical polymers with spectroscopically resolved domains and distinct morphologies. Using a combination of small-angle X-ray scattering and 19 F NMR relaxometry measurements, we connected differences in polymer structure and dynamics to polymer sequence variables such as the patchiness (density) of the structure forming monomer and the location of the chelating monomer. Furthermore, we found that, relative to calcium, all polymers in the series collapse more and have slower dynamics when binding REEs (lanthanum and lutetium) , though the extent of these effects were sequence-dependent and localized to specific domains within the polymer. Notably, sequence-controlled polymers that exhibited the largest conformational and dynamic changes upon binding REEs also bound REEs with the greatest affinity and modest selectivity. Collectively, these results correlate monomer patterning with dynamics, morphology, and REE binding performance en route to the development of efficient and selective macromolecular chelators.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
AREA 2: Novel Materials for Robust Repair of Leaky Wellbores in CO 2 Storage Formations
The potential leakage of hydrocarbon fluids or CO 2 out of subsurface formations through wells with fractured cement or debonded microannuli is a primary concern in oil and gas production and CO 2 storage. The presence of fractures in a cement annulus with apertures on the order of 10–300 microns can pose a significant leakage danger with effective permeability in the range of 0.1–1 mD (millidarcy). Leakage pathways with small apertures are often difficult to repair using conventional oilfield cement, thus a low-viscosity sealant that can be easily placed into these fractures while providing an effective seal is desired. The development of a novel application using pH-triggered polymeric sealants could potentially be the solution to plugging these fractures and that was the research aim of this study. The application is based on the transport and reaction of a low-pH poly(acrylic acid) polymer through fractures in strongly alkaline cement. The pH-sensitive microgels viscosify upon neutralization with cement to become highly swollen gels with substantial yield stress that can block fluid flow. Experiments in a cement fracture determined the effects of the viscosification and gel deposition via real-time visual observation and measurements of pressure gradient and effluent pH. While the pH-triggered gelling mechanism and rheology measurements of the neutralized polymer gel show promising results, the polymer solution in contact with cement undergoes an undesirable reaction known as polymer syneresis. Syneresis is caused by the release of calcium cation from cement that collapses the polymer network. Syneresis produces an unstable calcium-precipitation byproduct that is detrimental to the strength and stability of the gel in place. As a result, gel-sealed leakage pathways that subjected to various degrees of syneresis often failed to hold back pressures. Several chemicals were studied to inhibit polymer syneresis and tested for pretreatment of cement cores to remove calcium and prevent syneresis during polymer placement. A chelating agent, sodium triphosphate (Na 5 P 3 O 10 ), was found to successfully eliminate syneresis without compromising the injectivity of polymer solution during placement. Polymer gel strength is determined by recording the maximum holdback pressure gradients during liquid breakthrough tests after various periods of pretreatment and polymer shut-in time. Cores pretreated with Na 5 P 3 O 10 successfully held up to an average of 80 psi/ft, which is significantly greater than the expected threshold value of about 0.1-5 psi/ft required to prevent flow in a typical CO 2 leakage scenario. The use of such inexpensive, pH-triggered poly-acrylic acid polymer allows long-term robust seal of leaky wellbores under high pH conditions.
01 COAL, LIGNITE, AND PEAT↗
Utilization of mixed ligands to construct two new coordination polymers: Syntheses, structures and properties
The use of triazine and aromatic carboxylic acid as mixed chelating ligands in preparing two coordination polymers is described. Two new transition-metal coordination polymers, namely, [Co{sub 2}(bpdc){sub 4}(phdat){sub 2}] (1) and [Zn(bpdc)]{sub n} (2) (H{sub 2}bpdc=2,4-biphenyldicarboxylic acid, phdat=2,4-diamine-6-phenyl-1,3,5-triazine), have been hydrothermally synthesized and structurally characterized by IR, elemental analyses, X-ray single-crystal diffraction and TGA. Compound 1 is a 0D structure and extends to a 3D network by two different N–H···O and N–H···N hydrogen bonds. Compound 2 exhibits a 2D network with 4{sup 4}.6{sup 2} topological net, which contains two kinds of single helical chains. The interactions within each Co(II)–Co(II) pair of compound 1 are antiferromagnetic (g=2.19, J=−22 K, zj′=−0.00351 K). Furthermore, the photoluminescence property of 2 was also investigated in the solid state at room temperature. - Graphical abstract: Two polymeric metal compounds based on mixed-ligands were synthesized and characterized. The use of different metal ions results in distinct structures. The magnetic and fluorescent properties were also studied. - Highlights: • The first bpdc{sup 2−}/phdat-based 0D discrete coordination complex. • A new 2D architecture with two kinds of helical chains. • The structure-dependent magnetism and photoluminescence properties.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗