Molecular Systems Design & Engineering最新文献

Seven isostructural supramolecular adducts, [Ln₂(O₂CC₆H₃(NO₂)₂)₆(DMSO)₄]·4(1,4-(H₂N)₂C₆Me₄) (Ln = Sm (1), Gd (2), Tb (3), Dy (4), Ho (5), Er (6), Y (7)), were synthesized by reacting LnCl₃·6H₂O with potassium 3,5-dinitrobenzoate in acetonitrile in the presence of 2,3,5,6-tetramethyl-1,4-phenylenediamine (DAD) and DMSO, and characterized by X-ray diffraction analysis. The charge transfer (CT) between DAD molecules and binuclear 3,5-dinitrobenzoate fragments gives rise to stacking interactions, which determine the supramolecular structures of complexes 1–7. Optical spectroscopy of complexes 1–7 corroborates the occurrence of significant CT, whereas magnetic studies substantiate the presence of a paramagnetic ion-radical structure which contributes to the magnetic moment of all the complexes and determines the paramagnetism of the yttrium compound 7. In the case of the latter complex, the value of the paramagnetic contribution resulting from CT was determined directly by magnetic measurement. It was demonstrated that this contribution decreases with the lowering of temperature, reflecting the depopulation of the triplet state of the CT complex, the ion-radical pair. A comprehensive EPR study of complex 7 was carried out by means of both continuous-wave (CW) and pulsed EPR spectroscopy in X- and Q-bands. The magnetic properties of complexes 2–6 indicate the prevalence of weak antiferromagnetic interactions within the binuclear fragments. The Dy complex exhibits field-induced single-molecule magnet (SMM) behaviour. The CT in the complex structures was modelled using DFT calculations.

Visualizing singlet oxygen (¹O₂) in biological systems could greatly enhance our understanding of its biological roles and offer new diagnostics and therapeutics. However, ¹O₂ is unstable and highly reactive, making its detection in living systems a significant challenge. To address this, we have developed dually-labelled polymeric micelles designed to trace both the location and levels of ¹O₂.

The endeavor of utilizing non-radiative triplet excitons in RTP and TADF molecules has garnered significant interest in recent studies, presenting a highly desirable yet challenging pursuit. In this investigation, we utilized DFT and TD-DFT computational approaches to anticipate the photophysical characteristics of multifunctional materials, uncovering their significant reliance on the oxidation state and heavy atom influences of the chalcogen group on boron centered D(X)BNA cores, along with substitutions of weak phenylcarbazole (P-CBZ) and strong phenyldimethylacridine (P-DMAC) donors. The calculations demonstrated that both heavy atom (X = O, S, Se, Te) and oxidation (S, SO, SO₂, and Se, SeO) effects caused a decrease in singlet (S₁) and triplet (T₁) energies. Unexpectedly, the first singlet-triplet energy difference (ΔE_ST) values exhibit a systematic decrease with weak donor-based molecules, while they increase with strong donor unit-based molecules with the heavy atom effects. Moreover, the ΔE_ST values decrease systematically with the oxidation effect in both types of donor unit-based molecules. Conversely, the magnitudes of spin–orbit coupling (SOC) increase with heavy atom effects due to the orbital mixing and screening effects of lone pair electrons and decrease with oxidation effects because of their decreased lone pair electrons in both the S₁–T₁ and T₁–S₀ pathways. The elevated SOC and intersystem crossing (ISC) rates in heavy atom-based molecules, and low ΔE_ST and high reverse intersystem crossing (RISC) in oxidation-based molecules, meet the criteria for multifunctional RTP and TADF molecules, respectively.

Retrobiosynthesis tools harness the inherent promiscuities of enzymes for the de novo design of novel biosynthetic pathways to key small molecules. Many existing pathway search algorithms rely on exhaustively enumerating the space of all possible enzymatic reactions using generalized rules, followed by an extensive analysis of the ensuing reaction network to extract candidate pathways for experimental validation. While this approach is comprehensive, many false positive reactions are often generated given the permissiveness of such reaction rules. Here, we have developed DORA-XGB, a enzymatic reaction feasibility classifier. DORA-XGB can be used within our DORAnet framework to assess whether newly enumerated enzymatic reactions and pathways would be feasible. To curate a training dataset for our model, we extracted enzymatic reactions from public databases and screened them for their general thermodynamic feasibility. We then considered alternate reaction centers on known substrates to strategically generate infeasible reactions with high confidence, thereby circumventing the lack of negative data in the literature. In training our model, we also experimented with various molecular fingerprinting techniques and configurations for assembling reaction fingerprints, taking into account not just primary substrate and primary product structures, but cofactor structures as well. Our model's utility is demonstrated through favorable benchmarking against a previously published classifier, the successful recovery of newly published reactions, and the ranking of previously predicted pathways for the biosynthesis of propionic acid from pyruvate.

This research paper reports the synthesis of a super-porous hydrogel of xanthan gum with acrylamide (i.e., XG-SPH) with highly dense interconnected capillary channels and its application as a desiccant material to capture water vapors from humid air. For the generation of the porous structure with interconnected capillary channels, the polymer desiccant was synthesized via gas blowing, foaming and polymerization. The presence of interconnected capillary channels was observed in the scanning electron microscopy (SEM) images. The synthesized desiccant exhibited 0.27 g g⁻¹ adsorption capacity at 50% relative humidity and 25 °C which drastically increased to 1.38 g g⁻¹ at 25 °C and 90% relative humidity which suggested that the hydrophilic nature or the desiccant performance of the synthesized polymer desiccant increased with increasing relative humidity. The main driving force behind this high-water vapor adsorption capacity was the capillary condensation process which facilitated the adsorption or accommodation of more incoming water molecules at higher pressures. The adsorption of water molecules by the capillary condensation mechanism was further supported by the applicability of the type-III adsorption isotherm and the experimental data fitted well with the GAB adsorption isotherm. Moreover, the experimental kinetics data correlated well with the driving force model and indicated that water diffusion within the polymer structure followed a type II diffusion mechanism. The desorption kinetics indicated that the desorption occurred rapidly in the initial desorption stages, and most of the captured water was released within the first hour. Moreover, regenerating XG-SPH was energy efficient as it could be successfully regenerated at 50 °C and used for twenty adsorption–desorption cycles. The desiccant was able to retain almost 70% of its original adsorption capacity in the twentieth adsorption cycle. This suggests that gum polysaccharide-based super-porous hydrogels can extract or capture a considerable amount of water from the atmosphere without using any hygroscopic salt.

Selective nanoparticle surface patterning presents incredible promise for broadening programmable materials design into a space beyond “close-packed” morphologies. These “patchy” particles impose directional attractions between neighbors that favor the formation of low-coordination, open structures previously inaccessible via their isotropically interacting nanoparticle counterparts. However, unlike patchy colloids, patches on nanoparticles are highly deformable, presenting challenges for their predictive design. Here, we present a multi-faceted approach combining theory and simulation to investigate the underlying forces governing interactions between nanoparticles with flexible patches. We first develop a thermodynamic perturbation theory to fundamentally capture the interplay between patch–patch merging and directional entropic forces in controlling particle organization. We then employ theoretical insights to explicitly consider how monomer geometry synergizes with monomer connectivity in sculpting the equilibrium morphologies for polymeric chains composed of anisotropic monomeric subunits. Theory predictions are then validated using simulations, with excellent agreement across both local and global length scales. Combined, our findings indicate that a large suite of orientational and structural diversity can be attained via precision engineering of how patch–patch and entropic forces between the anisotropic nanoparticles counterbalance each other. These findings on nanoscale patchy interactions offer newer avenues for directing the assembly process of novel polymeric and metamaterials.

Wireframe DNA origami nanostructures present significant potential for a variety of applications in nanotechnology, primarily due to their straightforward design and construction processes. The precise control afforded by these nanostructures renders them exceptionally suitable for executing specific tasks. This study introduces innovative designs by altering short strands (staples) in wireframe DNA origami nanostructures, leading to different behaviors at human body temperature. These behaviors include the selective opening of certain parts of the structure while keeping other parts closed. Our research demonstrates that wireframe DNA origami nanostructures, with their numerous edges, can be engineered to allow selective opening of specific edges. This capability facilitates precise control over the structural configuration, enabling designers to customize these nanostructures to fulfill specific functional requirements. Consequently, the use of these controllable nanostructures opens up new avenues for developing nanorobots. By leveraging the unique properties of wireframe DNA origami, this study paves the way for advancements in the field of nanotechnology, particularly in the creation of versatile and adaptable nanoscale devices.

Glucose-responsive hydrogel systems are increasingly explored for insulin delivery, with dynamic-covalent crosslinking interactions between phenylboronic acids (PBA) and diols forming a key glucose-sensing mechanism. However, commonly used PBA and diol chemistries often have limited responsiveness to glucose under physiological concentrations. This is due, in part, to the binding of PBA to the commonly used diol chemistries having higher affinity than for PBA to glucose. The present study addresses this challenge by redesigning the diol chemistry in an effort to reduce its binding affinity to PBA, thereby enhancing the ability of glucose to compete with these redesigned PBA–diol crosslinks at its physiological concentration, thus improving responsiveness of the hydrogel network. Rheological analyses support enhanced sensitivity of these PBA–diol networks to glucose, while insulin release likewise improves from networks with reduced crosslink affinities. This work thus offers a new molecular design approach to improve glucose-responsive hydrogels for insulin delivery in diabetes management.

Substituent engineering is a key route to high-performance functional molecular materials in the same way as the development of a π-electron core for organic (opto-)electronics. Here we demonstrate a comparative study between aromatic phenyl- and aliphatic cyclohexyl-terminated side-chain substituents on an electron-deficient π-electron core, 3,4,9,10-benzo[de]isoquinolino[1,8-gh]quinolinetetracarboxylic diimide (BQQDI), to get insights into the impact of intermolecular interactions between the substituents in the solid state on high-performance electron-transport properties. In the BQQDI system, both phenyl- and cyclohexyl-terminated ethyl substituents show similar packing structures, demonstrating the unobvious impact of terminal groups. However, solution-processed single-crystal transistor studies revealed a relatively low electron mobility of cyclohexyl-terminated BQQDI. Based on molecular dynamics simulations, we attribute this discrepancy to dynamic molecular motions coupled with electronic coupling in the solid state. While phenyl groups in the phenylethyl substituent show intermolecular C–H⋯π interactions which lead to less dynamic motions, the cyclohexyl counterpart does not show any specific intermolecular interactions. Hence, a low-dynamic feature thanks to inter-side-chain interactions is promising for excellent charge-transport properties. The present findings underline the crucial role of interactions between substituents in the development of organic materials via side-chain-engineered control of the solid-state dynamic motions.

Herein, we have synthesized an ESIPT inbuilt novel tripodal gelator TH-AIL, which upon dissolution in DMSO followed by the addition of water (1 : 1) leads to the formation of a unique orange fluorescent organohydrogel (0.35% w/v, OHG). The obtained OHG reveals responses towards base NH₃ and acid HCl by way of reversible change in fluorescence colour from orange to green along with restorable conversion from gel to sol phase.