Anionic Groups Research Articles

Impact of charges on the hybridization kinetics and thermal stability of PNA duplexes.

Peptide nucleic acid (PNA) is a prominent artificial nucleic acid mimetic and modifications at the γ-position of the peptidic backbone are known to further enhance the desirable properties of PNA in terms of duplex stability. Here, we leveraged a propargyl ether modification at this position for late stage functionalization of PNA to obtain positively charged (cationic amino and guanidinium groups), negatively charged (anionic carboxylate and alkyl phosphonate groups) and neutral (PEG) PNAs to assess the impact of these charges on DNA : PNA and PNA : PNA duplex formation. Thermal stability analysis findings concurred with prior studies showing PNA : DNA duplexes are moderately more stable with cationic PNAs than anionic PNAs at physiological salt concentrations. We show that this effect is derived predominantly from differences in the association kinetics. For PNA : PNA duplexes, anionic PNAs were found to form the most stable duplexes, more stable than neutral PNA : PNA duplexes.

Single and binary adsorption of azo blue and mordant black 17 with vermiculites functionalized by amphoteric gemini surfactants: Performance and mechanism

Incorporation of amphoteric gemini surfactants into vermiculite (Vt) is a valuable task in developing clay application. Hereby amphoteric gemini surfactants with hydrophobic alkyl chains, dual N+ head groups and anionic functional groups are introduced to prepare organo-Vts as dye adsorbents. The adsorbents are labeled as TAES-Vt with sulfonic acid group and TABS-Vt with benzenesulfonic acid groups, respectively. Both single and binary adsorption towards azo blue (AB) and mordant black 17 (MB17) have been investigated. The max uptake amounts in single dye system are 189/177mg/g for AB and 278/406mg/g for MB17 by TAES-Vt/TABS-Vt, respectively. Furthermore, the presence of AB is favorable for the removal of MB17 in binary dye system, with adsorption capacities increasing to 449/469mg/g by TAES-Vt/TABS-Vt. However, MB17 exhibits an antagonistic effect on adsorption of AB, thus resulting lower AB removal capacities in binary dye system. The adsorption mechanisms are elucidated via adsorption, characterization and calculation. (i) Hydrophobic interaction, electrostatic interaction, H-bond, and electron donor effect all support the adsorption for AB/MB17. (ii) Compared to TABS-Vt, TAES-Vt has a slightly higher adsorption capacity for large-sized AB due to its larger interlayer spacing. However, TABS-Vt is better at adsorbing small-sized MB17 than TAES-Vt by vitue of additional benzene ring that can provide π-π interaction. (iii) In view of adsorbates, the difference of molecular size and structural property in AB and MB17 also affect adsorption. This work provides ideas for the multi functionalization of Vt, reviving the adsorption advantages of clay based materials.

The enhanced bandgap and birefringence of rare-earth phosphates XPO4 (X = Sc, Y, La, and Lu): a first-principles investigation.

Rare-earth phosphates were thought to be good candidates as ultraviolet/deep ultraviolet optical materials due to their relatively large bandgap and optical properties. In this paper, the authors screened out a family of XPO4 (X = Sc, Y, La, and Lu) compounds with an enhanced bandgap (HSE06 bandgap ≥ 7.61 eV) and birefringence (0.0934-0.2003@1064 nm) using first-principles calculations. The origin of enhanced optical properties was investigated using projected density of states, distortion indices, and Born effective charges. The results show that the PO4 anionic groups and X-O polyhedra give the main contribution in determining the optical properties, and the PO4 anionic groups give more contribution than other functional basic units. The spin-orbit interaction was also investigated. Similar band structures were found after spin-orbit coupling (SOC) was considered, and slightly enhanced birefringence was found when SOC was applied to these rare-earth phosphates.

New ultraviolet transparent rare-earth borates with enhanced birefringence induced by cation chemical substitution

In the three structures, the substitution of large-size cations results in the rearrangement of the anionic group, and their birefringence exhibits a progressive doubling increase, transitioning from 0.017, 0.033 to 0.070 at 532 nm.

Facile and affordable synthesis of sulfonated and phosphonated poly (p-terphenyl perfluorophenyl)s for proton exchange membrane fuel cells

Hydrocarbon proton exchange membranes (PEMs) which exhibit low-cost, improved robustness, and simple synthesis relative to perfluorosulfonic acid (PFSA) membranes, are of great significance for proton exchange membrane fuel cells (PEMFCs). Herein, we report a facile and affordable preparation of sulfonated and phosphonated poly (p-terphenyl perfluorophenyl)s PEMs via superacid-catalyzed Friedel−Crafts condensation of p-terphenyl and pentafluorobenzaldehyde monomers, following by highly selective para-substitution of fluorobenzene to graft ion exchange groups. The rigid and well-defined polymer structure with precisely controlled anionic groups, enables good phase separation and efficient ionic clustering to promote proton transport. Sulfonated and phosphonated PEMs show modest proton conductivities of 150 and 120 mS cm−1 at 90 °C, and achieve H2/air PEMFC peak power densities of 360 and 237 mW cm−2 at 80 ℃, respectively. Interestingly, we find that phosphonated PEMs have significantly higher resistance to free radicals than sulfonated PEMs. Overall, the results suggest that our prepared hydrocarbon PEMs have potential applications for fuel cells.

Combining photocontrolled-cationic and anionic-group-transfer polymerizations using a universal mediator: enabling access to two- and three-mechanism block copolymers.

An ongoing challenge in polymer chemistry is accessing diverse block copolymers from multiple polymerization mechanisms and monomer classes. One strategy to accomplish this goal without intermediate compatibilization steps is the use of universal mediators. Thiocarbonyl thio (TCT) functional groups are well-known mediators to combine radical with either cationic or anionic polymerization, but a sequential cationic-anionic universal mediator system has never been reported. Herein, we report a TCT universal mediator that can sequentially perform photocontrolled cationic polymerization and thioacyl anionic group transfer polymerization to access poly(ethyl vinyl ether)-block-poly(thiirane) polymers for the first time. Thermal analyses of these block copolymers provide evidence of microphase separation. The success of this system, along with the established compatibility of radical polymerization, enabled us to further chain extend the cationic-anionic diblock using radical polymerization of N-isopropylacrylamide. The resulting terpolymer represents the first example of a triblock made from three different monomer classes incorporated via three different mechanisms without any end-group modification steps. The development of this simple, sequential synthesis using a universal mediator approach opens up new possibilities by providing facile access to diverse block copolymers of vinyl ethers, thiiranes, and acrylamides.

Fucoidan's Molecular Targets: A Comprehensive Review of Its Unique and Multiple Targets Accounting for Promising Bioactivities Supported by In Silico Studies.

Fucoidan is a class of multifunctional polysaccharides derived from marine organisms. Its unique and diversified physicochemical and chemical properties have qualified them for potential and promising pharmacological uses in human diseases, including inflammation, tumors, immunity disorders, kidney diseases, and diabetes. Physicochemical and chemical properties are the main contributors to these bioactivities. The previous literature has attributed such activities to its ability to target key enzymes and receptors involved in potential disease pathways, either directly or indirectly, where the anionic sulfate ester groups are mainly involved in these interactions. These findings also confirm the advantageous pharmacological uses of sulfated versus non-sulfated polysaccharides. The current review shall highlight the molecular targets of fucoidans, especially enzymes, and the subsequent responses via either the upregulation or downregulation of mediators' expression in various tissue abnormalities. In addition, in silico studies will be applied to support the previous findings and show the significant contributors. The current review may help in understanding the molecular mechanisms of fucoidan. Also, the findings of this review may be utilized in the design of specific oligomers inspired by fucoidan with the purpose of treating life-threatening human diseases effectively.

Anion Substitution Strategy toward an Advanced NASICON-Na4Fe3(PO4)2P2O7 Cathode for Sodium-Ion Batteries.

Superior sodium-ion batteries (SIBs) greatly need cathode materials with higher capacity and better durability. Herein, the anion group substitution strategy is proposed to design a cathode material with extraordinary Na+ storage performance, NASICON-Na4Fe3(PO4)1.9(SiO4)0.1P2O7 (NFPP-Si0.1). The experimental and theoretical research revealed that modification in the local structure by anion substitution significantly boosts the ionic/electronic transfer kinetics via optimizing the electronic conductivity and reducing the Na+ diffusion energy barrier. Furthermore, the SiO44- substitution generates a slight expansion of the crystal lattice to broaden the Na+ diffusion channel. Specifically, the custom-designed NFPP-Si0.1 could deliver a high rate capability of 77.6 mAh g-1 at constant 50 C charge-discharge and excellent recyclability of 79.4% retention rate after 7000 cycles at 10 C. Besides, it also possesses outstanding low temperature reversible capacity of 95.5 mAh g-1 at 0.1 C and long-term cyclability of 93.6% capacity retention after 1000 cycles at 5 C in -10 °C. This strategy of heterogeneous and isostructural anion group substitution provides a method for unlocking high-rate and long-life-span mixed polyanionic cathodes.

Intramolecular electrostatic effects on reduction of CO2 to CO by iron porphyrin complexes: Insights from DFT calculations

Iron porphyrin (Por) complexes were found to be highly efficient molecular catalysts for electrocatalytic CO2 reduction and the catalytic performance can be modulated by the modification of ligands. Herein, density functional theory calculations were employed to investigate how the presence of second-sphere anionic carboxylate groups influences the CO2-to-CO conversion by Fe porphyrins. The kinetics and thermodynamics of individual chemical steps in the reaction cycle were systematically studied. Computations indicated that the catalytic active species is the ferrous complex with the two extra electrons being stored in the π system of porphyrin and the rate-determining step is the CO2 binding. The synchronization of the Fe-to-CO2 and ligand-to-Fe electron transfers leads to the formation of FeIII(CO22−)(Por•−). The experimentally observed activity trend could be rationalized by the Brønsted-Evans-Polanyi principle. The electrostatic repulsive between the negatively charged hanging group and the CO2 moiety destabilizes the CO2 adduct and thereby raises the binding energy. Then, the two-step protonation occurs easily to give Fe(II)-CO. The further one-electron reduction triggers the dissociation of CO to regenerate of the formal Fe(I) porphyrin catalyst. The insights gained from this study may be helpful in designing efficient electrocatalysts for CO2 reduction.

Elucidating the Role of Anion Groups in Lithium-Ion Diffusion

Since the 1960s, the paddlewheel effect has been proposed as a way to enhance lithium-ion diffusion in inorganic materials by using rotor-like anion groups to assist lithium-ion movement(1–5). However, so far the physical mechanism behind how anion-group dynamics affect lithium-ion diffusion has not been clearly understood. In this talk, we clearly define various types of rotational motions of anion-groups. Based on such definition, we detect and differentiate such distinct anion-group rotational motions throughout a total of 10’s of ns ab-initio molecular dynamics trajectories. By performing rigorous statistical analysis of various rotational events as well as lithium-ion diffusion events, we reveal how each type of anion rotational motions are related to lithium-ion diffusion. Our research has finally resolved the ongoing debate about the existence of the paddlewheel effect and provide a clear physical understanding of how anion-group rotations are related to fast ionic diffusion in inorganic materials. L. Karlsson, R. L. McGreevy, Mechanisms of ionic conduction in Li2SO4 and LiNaSO4: Paddle wheel or percolation? Solid State Ionics. 76, 301–308 (1995).A. Kvist, A. Lundén, Electrical Conductivity of Solid and Molten Lithium Sulfate. Zeitschrift Für Naturforschung. 20, 235–238 (1965).Z. Zhang, L. F. Nazar, Exploiting the paddle-wheel mechanism for the design of fast ion conductors. Nat Rev Mater, 1–17 (2022).J. G. Smith, D. J. Siegel, Low-temperature paddlewheel effect in glassy solid electrolytes. Nat Commun. 11, 1483 (2020).M. Jansen, Volume Effect or Paddle‐Wheel Mechanism—Fast Alkali‐Metal Ionic Conduction in Solids with Rotationally Disordered Complex Anions. Angewandte Chemie Int Ed Engl. 30, 1547–1558 (1991).

(Battery Division Student Research Award Sponsored by Mercedes-Benz Research & Development) Rationalizing Fast Lithium-ion Diffusion in Inorganic Lithium Superionic Conductors

All-solid-state batteries are gaining attention due to the potential advantage that solid electrolytes provide in terms of safety and energy density. Understanding the mechanism of fast lithium-ion diffusion in inorganic materials has become one of the key challenges in materials science. Among various factors that affect lithium mobility, the topology of the crystal structure strongly dictates which materials can accommodate fast lithium-ion motion. Despite this, the intrinsic mechanism that connects the lithium-ion diffusion to the structural feature of the crystal structure and motion of the non-diffusing framework remains unclear, hindering the rational design of novel fast-conducting solid electrolytes.This talk focuses on the fundamental understanding of the structure-property relationship of lithium-ionic conductivities. We first discuss the structural factors governing fast lithium-ion diffusion in oxide materials. We find that both the topology of the lithium-ion diffusion network as well as the connectivity of the non-diffusing framework strongly affect lithium-ions diffusion in oxide materials. Structural features that allow lithium superionic conductivity in oxide materials are identified, which led to the discovery of 16 novel fast lithium-ion conducting frameworks.In the second part of the talk, we present our statistical framework for understanding the correlation between anion-group rotational motion and lithium-ion translational motion. Using event-detection algorithms on long ab-initio molecular dynamics trajectories, we detect and differentiate various types of rotational motion of anion groups. This allows us to obtain a statistically rigorous understanding of how each type of anion group rotational motion affects lithium-ion diffusion events. These fundamental understandings provide design guidelines towards the development of fast-diffusing inorganic materials optimal for all-solid-state batteries.

Functionalized Nanoporous Ceramic Membranes for Electrodialysis Treatment of Harsh Wastewater

INTRODUCTION Electrodialysis (ED) is a well-developed technology for electrochemical desalination. However, many industries generate harsh wastewater streams that are incompatible with traditional ion exchange membranes and thus limit the use of ED. Membrion® has developed novel ceramic-based ion exchange membranes which offer a number of advantages over traditional polymer membranes: high performance in low pH, chemical resistance to oxidizers, and a rigid structure which minimizes membrane swelling. This presentation will discuss these novel membranes and their performance in electrodialysis stacks. EXPERIMENTAL Novel ceramic ion exchange membranes (IEM) are synthesized with patented silane-based sol-gel techniques. These ceramic membranes have covalently bound charged moieties similar to polymer IEMs; however, they are attached to a tunable nanoporous structure. The pore size, shape, and network structure are engineered through a molecular self-assembly process where thermodynamic driving forces are used to direct where and how pores form. Either cation (e.g., SO3 -) or anion (e.g., NH4 +) groups can be added within the membrane nanopore structure to enhance ion selectivity. The ceramic IEMs are produced on a roll-to-roll manufacturing line with low temperature processing. Membrane performance is assessed by measuring permselectivity (PS), area-specific resistance (ASR), and batch electrodialysis tests. RESULTS Figure 1 shows that both cation exchange membranes (CEM) and anion exchange membranes (AEM) show a decreased ASR compared to traditional polymer membranes, while maintaining comparable PS (i.e., the ability to separate cations and anions). The lower ASR of ceramic membranes is advantageous, as this can improve the overall energy efficiency of electrodialysis desalination. We maintain good performance (i.e., comparable current efficiency and water recovery) when integrated into a 10-cell pair stack. Most significantly, the right plot of Figure 1 shows a stable dilute water recovery of ~90% achieved with ceramic membranes after being stored in solutions ranging from pH 3 to pH 0 for 30 days. We have also demonstrated this technology in the field with copper wastewater generated at a microelectronics manufacturing facility. On site bench and pilot testing showed that our membranes could be used to nearly eliminate the copper sent to single-use IEX resin. DISCUSSION Ceramic-based ion exchange membranes are able to achieve comparable performance to traditional polymer membranes and offer some unique advantages. Long exposure to very low pH has negligible impact on ceramic ED stack performance. Additionally, we have observed stable performance in the presence of strong oxidizing agents such as hydrogen peroxide. This stability is expected, as the silica backbone of these materials is already in a fully oxidized state, as opposed to traditional polystyrene-based membranes. This data suggests ceramic membranes could be an ideal solution for acidic and/or oxidizing wastewater streams found in industries such as semiconductor manufacturing and mining. In addition to offering chemical stability in harsh environments, the patented silica sol-gel process used to cast these membranes is extremely tunable. Through incorporating commercially available functionalized silanes, the pore size and chemical make-up can be easily altered to target specific waste streams. CONCLUSIONS Ceramic ion exchange membranes are shown to have similar performance attributes to traditional polymer IEMs when evaluated for electrodialysis water purification applications. The good stack-level performance combined with stability in harsh environments have the potential to dramatically broaden the use of ED/EDR for industrial wastewater treatment. Figure 1

(C(NH2)3)2(I2O5F)(IO3)(H2O) and C(NH2)3IO2F2: Two Guanidine Fluorooxoiodates with Wide Band Gap and Large Birefringence.

Enhancing anisotropy through an effective synergistic arrangement of anionic and cationic groups is crucial for improving the birefringence optical properties of materials. In this work, by transforming I-O into I-F through the fluorination strategy, two metal-free guanidine fluorooxoiodates (C(NH2)3)2(I2O5F)(IO3)(H2O) and C(NH2)3IO2F2 and one guanidine iodate C(NH2)3IO3 were successfully synthesized using the hydrothermal method. An unprecedented dimer [I2O5F] formed by [IO3F] and [IO3] in (C(NH2)3)2(I2O5F)(IO3)(H2O) was found, which greatly enriches the structural diversity of fluorooxoiodates. All three compounds feature a relatively large birefringence (Δn = 0.068, 0.110 and 0.075 at 546 nm) and a short ultraviolet cutoff edge. The theoretical calculation was carried out to understand the electronic structures and linear optical properties.

Synthesis of a Conceptual New Single-Ion Conducting Polymer Electrolyte for All-Solid-State Batteries

The increasing global population and the rapid change in climatic conditions strengthens the demand for a more efficient handling of energy consumption and energy storage technologies. In this context, all-solid-state batteries (ASSBs) as next-generation rechargeable lithium-ion batteries offer an improved energy and power density based on the integration of novel separators and electrode materials. In comparison to their liquid representatives, ASSBs provide a higher intrinsic safety via non-flammable components and in addition greater long-term durability. In relation to common electrolyte classes, solid polymers stand out due to their good mechanical flexibility, easy film-formation ability, good contact supply between cell components, and lower production costs, favoring the application as electrolytes, protective coatings, as well as additives in cathode composites. Among a variety of polymers, poly(ethylene oxide) (PEO) is a well-studied and established host polymer due to its great ability to dissolve lithium salts like LiBH4, LiPF6 or LiTFSI. Based on a low glass transition temperature (Tg) of about - 60 to - 50 °C, PEO shows a high degree of polymer chain flexibility which facilitates the migration of the lithium cations through the solid electrolyte. Nevertheless, its semi-crystalline character often leads to low conductivities below its melting point (Tm) of around 60 °C, making pure PEO unattractive as solid electrolyte. Copolymerization, the addition of a small amount of solvent to produce so called gel polymer electrolytes, the addition of some plasticizers, or the interplay of polymer and inorganic fillers try to counteract this trend. The synthetical concept behind this work is aiming to benefit from the flexible nature of PEO, and at the same time to improve the ionic conductivities and especially the lithium migration by structural realignment away from a dual-ion towards a single-ion conducting polymer electrolyte (SICPE). The polar PEO-backbone ensures polymer chain mobility, whereas a rigid aromatic structure unit as side chain bears the fixed anionic group. The immobilization of the anionic charges on the polyether backbone tends to guide the electrolyte to higher lithium transference numbers, fewer polarization effects, and the suppression of dendrite growth, resulting in an overall improved cell performance. Synthesis steps via the novel SICPE are characterized with the help of nuclear magnetic resonance spectroscopy (NMR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Thermal analyses of the homopolymer already show the positive influence of the flexible PEO-backbone by lowering the Tg from 100 to 150 °C for related aliphatic derivatives down to 60 to 80 °C in our case. On the basis of electrochemical impedance spectroscopy (EIS) measurements, the interplay of chemical, thermal, and electrochemical key properties is investigated. The gained results tend to open a discussion panel concerning occurring challenges for solid-state polymer electrolytes and the interdependencies between electrolyte constitution and polymer characteristics.

A hierarchical C-S-H/organic superstructure with high stiffness, super-low porosity, and low mass density

Herein, a hierarchical cementitious calcium silicate hydrate (C-S-H) superstructure with high Young's modulus, super-low porosity, and low mass density is reported. It has a very high Young's modulus at 47.5 GPa, three times higher than our reference synthetic C-S-H. Its specific surface area is merely 0.4509 m2/g, two orders of magnitude smaller than our reference synthetic C-S-H and the most common construction materials. In addition, the skeletal density of this composite is 1.96 g/cm3, much lower than C-S-H and hardened cement paste. In a density-Young's modulus diagram, this composite is located at the intersection of metals, ceramics, and polymers, approaching the carbon fiber region, implying lightweight and stiff characteristics. The cryogenic stability is also evaluated. It shows a satisfying applicability potential for cryogenic engineering with stable pore structure and nanoscopic mechanical properties. We confirm that the assembly of hierarchical C-S-H superstructure requires both hydrophilic amide and anionic carboxylic groups.

Cd8(BO3)4SiO4: Metal Cation Inducing the Formation of Isolated [BO3] and [SiO4] Units in Borate Silicate.

The first compound of cadmium-borate silicate Cd8(BO3)4SiO4, crystallizing in space group P42/n (no. 86), has been successfully synthesized by the conventional high-temperature solution method and melts congruently. The zero-dimensional anionic groups of Cd8(BO3)4SiO4 are isolated [BO3] triangles and isolated [SiO4] tetrahedra which are filled in the framework formed by [CdO6] polyhedra. It has a moderate birefringence (Δn = 0.053 at 546 nm), which is measured by experiment and evaluated by first-principles calculations; meanwhile, the source of birefringence is revealed through the response electronic distribution anisotropy method. The UV-vis-NIR diffuse reflectance spectrum indicates that Cd8(BO3)4SiO4 possesses a wide optical transparency range, with a UV cutoff edge at about 254 nm. This work enriches the structure chemistry of borate silicates, and we discussed the possible methods for the exploration and synthesis of novel optical crystals possessing zero-dimensional anionic groups in the borate silicate system.

Ultra-broadband emission up to 181 nm of VO4-activated yellow phosphor for white light-emitting diodes with high color rendering index

Exploring broadband yellow phosphors capable of covering the cyan to red region is an effective approach to achieve high-performance phosphor-converted white light-emitting diodes (pc-WLEDs). Herein, we synthesized a series of VO4-activated ultra-broadband KSrP1−xVxO4 (0.1 ≤ x ≤ 1) yellow phosphors via high temperature solid-state reaction. Successive substitution of P5+ with V5+ causes a slight expansion of the lattice constant and induces several highly localized energy-levels within the forbidden band. Density functional theory calculations confirm that these newly appeared sharp-line energy-levels are attributed to the constructed VO4 anionic groups. With the optimized V5+ content, the KSrP0.7V0.3O4 phosphor exhibits an ultra-broadband yellow emission centered at 537 nm under 355 nm excitation. Impressively, its full width at half maximum is up to 181 nm, exceeding that of most reported counterparts. At 105 °C, the KSrP0.7V0.3O4 sample experiences an emission loss of 53%. A WLED device is fabricated by using phosphor blend of KSrP0.7V0.3O4 yellow phosphor and the commercial BaMgAl10O17: Eu2+ blue phosphor and a 355 nm NUV LED chip, demonstrating bright white emission with high color rendering index (CRI) of 90 and suitable correlated color temperature of 5953 K. These findings indicate that this phosphor has great potential for achieving high CRI WLEDs.

Reductive amination of oxidized hydroxypropyl cellulose with ω-aminoalkanoic acids as an efficient route to zwitterionic derivatives

Zwitterionic polymers, with their equal amounts of cationic and anionic functional groups, have found widespread utility including as non-fouling coatings, hydrogel materials, stabilizers, antifreeze materials, and drug carriers. Polysaccharide-derived zwitterionic polymers are attractive because of their sustainable origin, potential for lower toxicity, and possible biodegradability, but previous methods for synthesis of zwitterionic polysaccharide derivatives have been limited in terms of flexibility and attainable degree of substitution (DS) of charged entities. We report herein successful design and synthesis of zwitterionic polysaccharide derivatives, in this case based on cellulose, by reductive amination of oxidized 2-hydroxypropyl cellulose (Ox-HPC) with ω-aminoalkanoic acids. Reductive amination products could be readily obtained with DS(cation) (= DS(anion)) up to 1.6. Adduct hydrophilic/hydrophobic balance (amphiphilicity) can be influenced by selecting the appropriate chain length of the ω-aminoalkanoic acid. This strategy is shown to produce a range of amphiphilic, water-soluble, moderately high glass transition temperature (Tg) polysaccharide derivatives in just a couple of efficient steps from commercially available building blocks. The adducts were evaluated as crystallization inhibitors. They are strong inhibitors of crystallization even for the challenging, poorly soluble, fast-crystallizing prostate cancer drug enzalutamide, as supported by surface tension and Flory–Huggins interaction parameter results.

Interaction of Polyanionic and Polycationic Brushes with Globular Proteins and Protein-like Nanocolloids.

A large number of experimental studies have demonstrated that globular proteins can be absorbed from the solution by both polycationic and polyanionic brushes when the net charge of protein globules is of the same or of the opposite sign with respect to that of brush-forming polyelectrolyte chains. Here, we overview the results of experimental studies on interactions between globular proteins and polycationic or polyanionic brushes, and present a self-consistent field theoretical model that allows us to account for the asymmetry of interactions of protein-like nanocolloid particles comprising weak (pH-sensitive) cationic and anionic groups with a positively or negatively charged polyelectrolyte brush. The position-dependent insertion free energy and the net charge of the particle are calculated. The theoretical model predicts that if the numbers of cationic and anionic ionizable groups of the protein are approximately equal, then the interaction patterns for both cationic and anionic brushes at equal offset on the "wrong side" from the isoelectric point (IEP), i.e., when the particle and the brush charge are of the same sign, are similar. An essential asymmetry in interactions of particles with polycationic and polyanionic brushes is predicted when fractions of cationic and anionic groups differ significantly. That is, at a pH above IEP, the anionic brush better absorbs negatively charged particles with a larger fraction of ionizable cationic groups and vice versa.

Theoretical investigation of the vibrational and electronic properties of tetraphenylammonium and its boron, aluminum, gallium, carbon, silicon, germane, phosphorus and arsenic analogues

Tetraphenyl ammonium (Ph4N+ ) has long been considered a phantom ion due to the difficulty in synthesizing aryl ammonium compounds. Following the successful synthesis of Ph4N+ last year (2022), the equilibrium geometries of Ph4X (X = B-, Al-, and Ga- of group 13; C, Si, and Ge of group 14; and P+ and As+ of group 15) have been optimized using the B3LYP/6-31G(d,p) method with no symmetry constraints. According to the optimized structural data, Ph4N+ is considered the most sterically hindered molecule in this series of compounds, which reflects the difficulty of its synthesis. The calculated total energies of the Ph4X compounds reveal that their energies decrease down the group, and the cationic forms (group 15) are less energetic than their neutral (group 14) and anionic (group 13) counterparts. The optimized geometrical parameters were used to compute the UV–vis, IR, 1H NMR, and 13C NMR spectra of the nine terephenyl compounds. The frontier molecular orbital energies were used to determine ionization potentials, electron affinity, and other global reactivity descriptors of the nine Ph4X compounds. An accurate assignment of vibrational bands was made using the potential energy distribution (PED) method. The B3LYP/6-31G(d,p) method yielded good agreement with available experimental data for the molecules. The low HOMO-LUMO gaps suggest potential nonlinear optical properties of these compounds.