Rotational Freedom Research Articles

Near-Infrared Probes Designed with Hemicyanine Fluorophores Featuring Rhodamine and 1,8-Naphthalic Derivatives for Viscosity and HSA Detection in Live Cells.

This paper presents the development of near-infrared (NIR) fluorescent probes, A and B, engineered from hemicyanine dyes with 1,8-naphthalic and rhodamine derivatives for optimized photophysical properties and precise mitochondrial targeting. Probes A and B exhibit absorption peaks at 737 nm and low fluorescence in phosphate-buffered saline (PBS) buffer. Notably, their fluorescence intensities, peaking at 684 (A) and 702 nm (B), increase significantly with viscosity, as demonstrated through glycerol-to-PBS ratio experiments. This increase is attributed to restricted rotational freedom in the fluorophore and its linkages to rhodamine or 1,8-naphthalic groups. Theoretical modeling suggests nonplanar configurations for both probes, with primary absorptions in the rhodamine and hemicyanine cores (A: 543; B: 536 nm), and additional transitions to 1,8-naphthalic (A: 478 nm) and rhodamine (B: 626 nm) groups. Probe A is also responsive to human serum albumin (HSA), a key biomarker, with fluorescence increasing in HeLa cells as HSA concentrations rise. In contrast, probe B shows no response to HSA, likely due to steric hindrance from its bulky rhodamine group, illustrating a selectivity difference between the probes. Probe B, however, excels in mitochondrial imaging, confirmed through cellular and in vivo studies. In HeLa cells, it tracked viscosity changes following treatment with monensin, nystatin, and lipopolysaccharide (LPS), with fluorescence increasing in a dose-dependent manner. In fruit flies, probe B effectively detected monensin-induced viscosity changes, demonstrating its stability and in vivo applicability. These findings highlight the versatility and sensitivity of probes A and B as tools in biological research, with potential applications in monitoring mitochondrial health, detecting biomarkers like HSA, and investigating mitochondrial dynamics in disease.

The effect of fabrication procedures and thermomechanical loading on the structural properties of screw-retained metal-ceramic implant restorations: An in vitro study.

Metal-ceramic screw-retained implant restorations persist as a fundamental choice in specific clinical scenarios. Little is known about the effects of fabrication steps and aging on their structural properties. This study aimed to investigate how laboratory fabrication procedures and thermomechanical loading affect the structural properties of screw-retained metal-ceramic implant restorations. Ten screw-retained metal-ceramic restorations were conventionally cast using UCLA chromium-cobalt overcast abutments. After 500 cycles of thermocycling and 500,000 cycles of mechanical loading, changes in connection dimensions and rotational freedom (RF) were measured and compared at various fabrication steps and post-thermomechanical loading. A generalized estimating equations (GEE) model was employed to analyze trends across the studied time points within the fabrication stage and after thermomechanical loading, with LSD post-hoc tests applied for pairwise comparisons. The level of significance was set at α = 0.05. Significant changes were observed across the analyzed time points: the average hexagonal side length (L) decreased (p < 0.001), and the average hexagonal angle deformation (P) increased, with notable differences observed in most comparisons between different fabrication steps (p < 0.001). Short (T1) and long (T2) diagonals of the hexagon showed downward trends (p < 0.001), while concentricity (O) and RF increased (p < 0.001), except between porcelain firing and loading steps for RF (p = 0.637). Casting had the greatest impact on variations in O (93.33%), T1 (88.88%), and T2 (45%), while porcelain firing significantly affected L (71.42%), P (71.42%), with the greatest effect on RF (75.32%). The fabrication processes and simulated clinical use adversely impacted the structural integrity and RF of abutments in screw-retained chromium-cobalt overcast implant restorations.

Structural dynamics and binding of Caenorhabditis elegans lifespan-extending lipid binding protein-3 to polyunsaturated fatty acids.

Intracellular lipid binding proteins (iLBPs) play crucial roles in lipid transport and cellular metabolism across the animal kingdom. Recently, a fat-to-neuron axis was described in Caenorhabditis elegans, in which lysosomal activity in the fat liberates polyunsaturated fatty acids (PUFAs) that signal to neurons and extend lifespan with durable fecundity. In this study, we investigate the structure and binding mechanisms of a lifespan-extending lipid chaperone, lipid binding protein-3 (LBP-3), which shuttles dihomo-γ-linolenic (DGLA) acid from intestinal fat to neurons. We present the first high-resolution crystal structure of LBP-3, which reveals a classic iLBP fold with an unexpected and unique homodimeric arrangement via interstrand interactions that is incompatible with ligand binding. We identify key ionic interactions that mediate DGLA binding within the lipid binding pocket. Molecular dynamics simulations further elucidate LBP-3's preferential binding to DGLA due to its rotational freedom and access to favorable binding conformations compared to other 20-carbon PUFAs. We also propose that LBP-3 dimerization may be a unique regulatory mechanism for lipid chaperones.

Recasting the wobbling-in-a-cone model for the rotational anisotropy of phenylselenocyanate in poly(methyl methacrylate): Effect of internal bond rotation and polymer segmental motion.

The rotational anisotropy of a molecule in a constrained environment is modeled by wobbling-in-a-cone (WIAC) motion, which describes the angular space sampled by the molecule. Recent polarization-selective IR pump-probe measurements have applied this model to phenylselenocyanate in amorphous polymers, aiming to probe the surrounding free volume. A faster rotational timescale was hypothesized to reflect the angular space within the static voids of the polymer matrix, while a slower timescale relates to constraint release by the polymer backbones. To better quantify the contributions of internal bond rotation and polymer segmental motion, we conduct molecular dynamics simulations on two phenylselenocyanate variants with different internal rotational barriers, as well as on p-chlorobenzonitrile, which lacks such internal rotational freedom, within a polymer matrix. Our analyses reveal that the faster (∼10ps) component of the cyano group's anisotropy decay arises from concurrent angular sampling due to internal bond rotation and WIAC motion. Conversely, polymer segmental motion was found to have a minimal influence on the slow (∼200ps) anisotropy component. Based on these findings, we refine the WIAC model to better link rotational diffusion with the distinct free volume elements accessed by the probe molecule. This revised model allows the quantification of free volume elements associated with both internal bond rotation and wobbling motion within the polymer cage.

Transformation Decoupling Strategy Based on Screw Theory for Deterministic Point Cloud Registration With Gravity Prior.

Point cloud registration is challenging in the presence of heavy outlier correspondences. This paper focuses on addressing the robust correspondence-based registration problem with gravity prior that often arises in practice. The gravity directions are typically obtained by inertial measurement units (IMUs) and can reduce the degree of freedom (DOF) of rotation from 3 to 1. We propose a novel transformation decoupling strategy by leveraging the screw theory. This strategy decomposes the original 4-DOF problem into three sub-problems with 1-DOF, 2-DOF, and 1-DOF, respectively, enhancing computation efficiency. Specifically, the first 1-DOF represents the translation along the rotation axis, and we propose an interval stabbing-based method to solve it. The second 2-DOF represents the pole which is an auxiliary variable in screw theory, and we utilize a branch-and-bound method to solve it. The last 1-DOF represents the rotation angle, and we propose a global voting method for its estimation. The proposed method solves three consensus maximization sub-problems sequentially, leading to efficient and deterministic registration. In particular, it can even handle the correspondence-free registration problem due to its significant robustness. Extensive experiments on both synthetic and real-world datasets demonstrate that our method is more efficient and robust than state-of-the-art methods, even when dealing with outlier rates exceeding 99%.

Cross-Shaped Peg-in-Hole Autonomous Assembly System via BP Neural Network Based on Force/Moment and Visual Information

Currently, research on peg-in-hole (PiH) compliant assembly is predominantly limited to circular pegs and holes, with insufficient exploration of various complex-shaped PiH tasks. Furthermore, the degree of freedom for rotation about the axis of the circular peg cannot be constrained after assembly, and few studies have covered the complete process from autonomous hole-searching to insertion. Based on the above problems, a novel cross-shaped peg and hole design has been devised. The center coordinates of the cross-hole are obtained during the hole-searching process using the three-dimensional reconstruction theory of a binocular stereo vision camera. During the insertion process, 26 contact states of the cross-peg and the cross-hole were classified, and the mapping relationship between the force-moment sensor and relative errors was established based on a backpropagation (BP) neural network, thus completing the task of autonomous PiH assembly. This system avoids hand-guiding, completely realizes the autonomous assembly task from hole-searching to insertion, and can be replaced by other structures of pegs and holes for repeated assembly after obtaining the accurate relative pose between two assembly platforms, which provides a brand-new and unified solution for complex-shaped PiH assembly.

水性レドックスフロー電池用アントラキノン系陽極液の機能化

Redox flow batteries (RFBs) are developed as grid-scale load-leveling technologies for renewable energy. Commercial RFBs use vanadium ions as active materials. However, their low energy density and high cost hinder wide deployment in electrical grids. To address these issues, 2,2′-(anthraquinone-2,6-diyldioxy)dipropionic acid (1Me) was reported as an aqueous anolyte to achieve two-electron redox capability, long cycle life, and high solubility.1 In this work, we improve the cycle stability by introducing a sterically bulkier substituent into the side chain of the anthraflavic acid derivative: 2,2′-(anthraquinone-2,6-diyldioxy)dibutyric acid (1Et; Figure 1). 1Et was synthesized by introducing methyl 2-bromobutyrate into anthraflavic acid, followed by saponification and subsequent neutralization with hydrochloric acid. Both 1Me and 1Et exhibit a redox potential of −0.68 V (vs. Ag/AgCl) in 1 mol L−1 KCl and 0.01 mol L−1 KOH aqueous solutions, indicating little influence of the substituent modification to a redox potential. Interestingly, 1Et shows higher solubility (1.73 mol L−1) than 1Me (1.54 mol L−1) despite an elongated hydrophobic alkyl side chain moiety. An ethyl group possesses a higher degree of freedom for rotation and vibration than a methyl group, resulting in larger dissolution entropy and hence higher solubility. Charge/discharge measurements using an H-type cell reveal that 1Et shows a higher capacity retention (0.029%/cycle) than that of 1Me (0.047%/cycle) (Figure 2) owing to a bulkier substituent preventing from nucleophilic attack on the side chain of anthraquinone. Levich analyses show comparable diffusion coefficients for 1Et (4.55×10−6 cm2 s−1) and 1Me (3.26×10− 6 cm2 s−1). These results demonstrate that introducing a bulkier substituent is an effective strategy to improve solubility in water and cycle stability without degrading other physical properties (e.g., redox potential and diffusivity).Reference[1] R. G. Godon, M. J. Aziz, et al., ACS Energy Lett. 2023, 8, 600. Figure 1

Synthesis and Characterization of Dicationic Ionic Liquids with the Difluorophosphate Anion

Dicationic ionic liquids (DILs) can be diversely designed by tuning spacer and cationic-center structure. Their features possibly superior to conventional ionic liquids include thermal stability, wide potential window, and high Li ion transference number, which make them good electrolyte candidates for secondary batteries. However, there are few reports of DILs and many unknown factors about the relationship between their structure and physical properties.Although Li[PO2F2] is known as an additive in lithium secondary batteries that improves the negative electrode performance, [1] PO2F2 - itself forms ionic liquids with a variety of onium cations. [2] In this study, we attempted syntheses of DILs with PO2F2 -, especially the ones with ether oxygen in the spacer and evaluated the physical properties of the resulting DILs.The synthesis of DILs was carried out in three steps. Initially, ethylene glycol was reacted with paraformaldehyde and trimethylsilyl chloride in dichloromethane at room temperature to prepare 1,2-bis(chloromethoxy)ethane. In the second step, dihalide reacted with two equivalents of amines at room temperature and converted to the corresponding chloride salts. Finally, the chloride salts and K[PO2F2] were reacted in dichloromethane at room temperature to exchange anions.According to the results of differential scanning calorimetry, the dication salts with ether spacer exhibit lower melting points than the corresponding dication salts without ether spacer owing to the flexibility around the ether group. Comparison of densities between pyrrolidinium- and linear alkylammonium-based DILs revealed the higher density of the former salt, which arises from the rotational freedom of the alkyl chain in the latter. The higher viscosity of the DIL with BF4 - than that of the DIL with PO2F2 - is due to the high dipole moment and thus polarity of PO2F2 - consisting of two oxygen and two fluorine atoms. High ionic conductivity is an important factor as electrolyte. The ion conductivity of the DIL with PO2F2 - is higher than that of the DIL with BF4 -, which implies the potential of PO2F2 - DILs in battery applications.

Dynamics of water, CO2, ethane and their mixtures in ZSM-22 zeolite: the role of polarity and hydrogen bonding

Abstract Understanding the interplay between confinement effects and intermolecular interactions is essential for predicting molecular diffusion in zeolites. In this study, we investigate the diffusion behavior of ethane, CO2, and water in ZSM-22 molecular sieves, focusing on the effects of mixing these fluids. Our results reveal that while CO2 has minimal impact on ethane diffusion, water significantly slows ethane’s motion by forming molecular bridges across the pore structure, reducing ethane’s diffusion by up to 30%. Ethane, in turn, restricts water’s mobility, and reduces the water–water coordination number from 2.22 to 0.73 depending on concentration. The diffusion of CO2 in mixtures shows a 40% increase in pure state under confinement. The role of polarity and hydrogen bonding is crucial, with water molecules exhibiting 1.2 hydrogen bonds in the confined state—much lower than the 3.4 bonds in bulk water. Molecular rotation in ZSM-22 of all fluids occurs at two distinct time scales: the short-time fast rotation dominated by molecular inertia and the long-time rotation hindered by fluid-zeolite interactions. For water, hydrogen bonding further restricts full rotational freedom. These findings provide a comprehensive understanding of how ethane, water, and CO2 interact and diffuse in nanoporous materials.

Two-Step Chemical Vapor Deposition for Fabrication of FAPbI3 Single-Crystal Microsheets with High Exciton Binding Energy.

Hybrid perovskites exhibit highly efficient optoelectronic properties and find widespread applications in areas such as solar cells, light-emitting diodes, photodetectors, and lasers. Here, we report the innovative synthesis of formamidinium lead iodide (FAPbI3) single-crystal microsheets via a two-step chemical vapor deposition (CVD) method. The microsheets exhibit hexagonal and trapezoidal shapes, with hexagonal FAPbI3 growing parallel to the substrate and trapezoidal FAPbI3 growing perpendicular to the substrate. The dominant role of single-exciton recombination in the photoluminescence (PL) of these microsheets is observed, especially pronounced at low temperatures, attributed to the relatively large exciton binding energies of the samples. Calculations reveal exciton binding energies as high as 110.8 meV for hexagonal and 133.3 meV for trapezoidal FAPbI3 single-crystal microsheets, attributed to reduced rotational freedom of the formamidinium (FA) ions. Further investigation into low-temperature phase transitions indicates lower transition temperatures (around 100 K) for these microsheets, suggesting reduced FA ion rotational freedom and consequently higher exciton binding energies.

The metastructures actuated by rotational motion with quasi-zero stiffness, negative stiffness, and bistability

In this paper, a mechanical metastructure actuated by rotational motion is proposed, which consists of several cosine beams and two supporting frames, with its mechanical properties tuned by the remaining shape of the beam concerning the size of the inner frame. The finite element method combining the experiments is adopted to explore the effect of geometric parameters and identify the variation of mechanical properties with the size of the inner frame, exhibiting different features including positive stiffness, quasi-zero stiffness, negative stiffness, and bistability. An angle difference describing the geometric relationship between the beam and the inner frame is employed to relate the mechanical properties. For the maximized angle difference, the quasi-zero stiffness is obtained and the bistability is easy to capture when the angle difference is around zero. Next, the quasi-zero stiffness feature and bistability are investigated in parametric analysis concerning the shape of the beam and offset distance, respectively, and the double-layer structures with two-step quasi-zero stiffness feature or multistability are designed to expand the design space of the proposed structure. The metastructure in this work provides a new option for designing multistable structures with rotational deformation freedom and developing torsional vibration isolators.

The Interior Contact-Aided Rolling Element

Abstract This work introduces an interior contact-aided rolling element (I-CORE) compliant mechanism that draws upon the concepts used for the contact-aided rolling element, cross-axis flexural pivot, and pre-curved flexible beam. The I-CORE incorporates a bilinear compressive stiffness response with an initial tailorable stiffness governed by the flexural geometry, followed by a stiffness curve governed by the material stiffness at the contact point. The I-CORE mechanism can achieve one or two degrees of rotational freedom as well as a single degree of translational freedom. The purpose of the present work was to introduce the I-CORE mechanism, as well as a pseudo-rigid-body replacement model (PRBM) of the I-CORE mechanism which was subsequently validated using both finite element analysis and benchtop mechanical testing. A pseudo-rigid body model was created for the I-CORE to simplify the rapid adaptation of this mechanism to different design applications. This model was validated using both finite element analysis and benchtop mechanical testing under both compression and rotation loading conditions. Additionally, multiple configurations of the device were created and evaluated in order to test its sensitivity to certain design features including the flexure width, flexure thickness, and the radius of the rounded contact surfaces. It was found that the model is sensitive to the thickness of the flexures and that despite some limitations, the pseudo-rigid body model is sufficiently accurate for initial design work. Some possible applications of the mechanism are proposed.

Two‐Coordinate Gold(I) Complex with Rotational Freedom: A Platform Integrating Thermally Activated Delayed Fluorescence, Polymorphism, and Linearly Polarized Luminescence

AbstractTwo‐coordinate coinage metal complexes have been exploited for various applications. Herein, a new donor‐metal‐acceptor (D–M–A) complex PZI‐Au‐TOT, using bulky pyrazine‐fused N‐heterocyclic carbene (PZI) and trioxytriphenylamine (TOT) ligands, was synthesized. PZI‐Au‐TOT displays decent thermally activated delayed fluorescence (TADF) with a quantum yield of 93 % in doped film. The crystals of PZI‐Au‐TOT show simultaneous TADF, polymorphism, and linearly polarized luminescence (LPL). The polymorph‐dependent emission properties with widely varied peaks from 560 to 655 nm are attributed to different packing modes in terms of isolated monomers, discrete π–π stacked dimers or dimer PLUS. Two well‐defined microcrystals of PZI‐Au‐TOT exhibit linearly polarized thermally activated delayed fluorescence with a degree of polarization up to 0.64. This work demonstrates that the molecular rotational flexibility of D–M–A type complexes endows an integration of multiple functions into one complex through manipulation of supramolecular aggregation. This type of complexes is expected to serve as a versatile platform for the fabrication of crystal materials for advanced photonic applications.

Two-Coordinate Gold(I) Complex with Rotational Freedom: A Platform Integrating Thermally Activated Delayed Fluorescence, Polymorphism, and Linearly Polarized Luminescence.

Two-coordinate coinage metal complexes have been exploited for various applications. Herein, a new donor-metal-acceptor (D-M-A) complex PZI-Au-TOT, using bulky pyrazine-fused N-heterocyclic carbene (PZI) and trioxytriphenylamine (TOT) ligands, was synthesized. PZI-Au-TOT displays decent thermally activated delayed fluorescence (TADF) with a quantum yield of 93 % in doped film. The crystals of PZI-Au-TOT show simultaneous TADF, polymorphism, and linearly polarized luminescence (LPL). The polymorph-dependent emission properties with widely varied peaks from 560 to 655 nm are attributed to different packing modes in terms of isolated monomers, discrete π-π stacked dimers or dimer PLUS. Two well-defined microcrystals of PZI-Au-TOT exhibit linearly polarized thermally activated delayed fluorescence with a degree of polarization up to 0.64. This work demonstrates that the molecular rotational flexibility of D-M-A type complexes endows an integration of multiple functions into one complex through manipulation of supramolecular aggregation. This type of complexes is expected to serve as a versatile platform for the fabrication of crystal materials for advanced photonic applications.

Reshaping the aggregation landscape of benzothiadiazole employing steroidal scaffolds and conformationally free alkyne tethers

In this study, we target the introduction of conformational freedom to BTD, aiming to unlock new solid-state arrangements that were previously inaccessible, while striving to maintain its high fluorescence quantum yield. Our approach is grounded in a detailed exploration of the conformational space of designed molecules, employing molecular mechanics to predict and evaluate the impact of structural modifications on solubility and solid-state behavior. By strategically flanking the BTD core with steroidal fragments through alkyne bridges, we not only introduce bulky elements that disrupt the native crystal-packing landscape of pristine BTD, but also ensure significant rotational freedom around the carbon-carbon triple bonds. This design strategy allows the molecules to explore a wide range of conformations, potentially facilitating the formation of novel solid-state supramolecular arrangements.The synthesis of these compounds revealed that they exhibit adequate processability in solution and form solids that prove crystalline by powder X-ray diffraction, but do not readily form macroscopic crystals as BTD normally does. The steroid fragments play a crucial role in determining the supramolecular organization of these compounds. Depending on the specific functional groups present on the steroid skeleton, primary interactions such as hydrogen bonding and secondary interactions related to facial amphiphilicity dictate the overall arrangement of molecules in the solid state.Remarkably, the modifications successfully preserve the intrinsic high fluorescence quantum yield of the BTD core. This achievement underscores the potential of incorporating conformational flexibility into molecular design to access new material properties while retaining desirable photophysical characteristics.

Non-limited vibrational effect on shock-induced phase transitions of condensed fluid in hard-sphere model

The essence of fluid phase transition is the jump of physical properties distinctly induced by shock waves in the hard-sphere model. Due to the strong impact of the wave, the internal freedoms of molecules are stimulated, releasing tremendous energy that commonly triggers the phase transition. Conversely, typical thermal and dynamic jumps can be described by the Rankine–Hugoniot conditions based on the Euler equation. In the theoretical simulation, the initial density and rotational freedoms of molecules are directly regarded as the primary factors to affect processes of phase transition. However, the influence of vibrational freedom in molecules has not been discussed yet. As the increasing temperature can gradually excite the affection of vibrational freedom, it is unwise to assume that the temperature element is constant in the theory. What would be a suitable model that accurately reflects the relationship between temperature and affection from vibrational freedom? The non-limited model has been courageously attempted with the temperature range from T0 to 6T0 (T0 is unperturbed temperature). We have found that the vibrational freedom can have a great effect on properties during phase transition processes.

Towards combining backbone and sugar constraint in 3'-3' bis-phosphonate tethered 2'-4' bridged LNA oligonucleotide trimers.

Therapeutic oligonucleotides are chemically modified to enhance their drug-like properties - including binding affinity for target RNA. Many nucleic acid analogs that enhance RNA binding affinity constrain the furanose sugar in an RNA-like sugar pucker. The improvements in binding affinity result primarily from increased off-rates with minimal effects on on-rates for hybridization. To identify alternate chemical modification strategies that can modulate on- and off-rates for oligonucleotide hybridization, we hypothesized that extending conformational restraint across multiple nucleotides could modulate hybridization kinetics by restricting rotational freedom of the sugar-phosphate backbone. As part of that effort, we recently reported that using hydrocarbon tethers to bridge adjacent phosphodiester linkages as phosphonate tethered bridges can pre-organize nucleic acids in conformations conducive for Watson-Crick base-pairing and modulate hybridization kinetics. In this report, we describe the synthesis of locked nucleic acid (LNA) trimers linked through alkylphosphonate tethers which restrict conformation of the furanose sugar in addition to restricting conformational mobility of the sugar-phosphate backbone across three nucleotide units.

Simulating the Entire Clinical Process for an Implant-Supported Fixed Prosthesis: In Vitro Study on the Vertical Implications of Implant-Abutment Connections and Rotational Freedom.

The aim of this in vitro study was to investigate whether and to what extent different scenarios of rotational freedom in different IAC designs affect the vertical dimension of a three-part fixed partial denture (FPD). At the same time, the experimental setup should simulate all clinical and laboratory steps of the implementation of such an FPD as accurately as possible. Twenty identical pairs of jaw models were fabricated from aluminum, each lower-jaw model holding two implants with conical or flat IACs. Three impressions of each model were taken to fabricate stone casts and three-unit FPDs. Three assembly scenarios were compared for the vertical position stability they offered for these FPDs, differing by how the sequential implant components (impression posts > laboratory analogs > abutments 1 > abutments 2) were aligned with the positional index of the IAC. In this way, a total of 60 stone casts and FPDs were fabricated and statistically analyzed for changes in vertical dimension (p < 0.05). Regardless of whether a conical/flat IAC was used (p > 0.05), significantly greater mean changes in vertical dimension were consistently (all comparisons p < 0.0001) found in a "worst-case scenario" of component alignment alternating between the left- and right-limit stop of the positional index (0.286/0.350 mm) than in a "random scenario" of 10 dentists and 10 technicians with varying levels of experience freely selecting the alignment (0.003/0.014 mm) or in a "best-case scenario" of all components being aligned with the right-limit stop (-0.019/0.005 mm). The likelihood of integrating a superstructure correctly in terms of vertical dimension appears to vary considerably more with assembly strategies than with IAC designs. Specifically, our findings warrant a recommendation that all implant components should be aligned with the right-limit stop of the positioning index.

N, N-Dimethylformamide assisted matrix to realize carbon nanomaterials from fluorescence to afterglow

Carbon nanomaterials (CNMs) with afterglow property have received extensive attention and are of great help to luminescent functional materials. However, it is still challenging to realize the afterglow properties of CNMs, such as the effective realization of afterglow and stable afterglow properties. In this work, we processed boric acid (BA) with N, N-dimethylformamide (DMF) to form a matrix by microwave, modified the CNMs produced by benzene-1,3.5-tricarboxylic acid (BTA) and tetraethylenepentamlne (TEPA) in two steps, and successfully prepared CNMs with yellow or green afterglow characteristic. The rotational freedom of the first-step material is limited by the formation of a BA-MDF matrix, which effectively suppresses the nonradiative transition and triple exciton deactivation, and the presence of a rigid structure limits the spin-orbit coupling (SOC) and promotes the energy levels to jump to the triple state to realize the afterglow properties. In addition, we used CNMs with afterglow as two-dimensional color block arrangement materials to realize anti-counterfeiting and information encryption, which has certain application value for related fields.

Effect of tert‐Butylation on the Photophysics of Thermally Activated Delayed Fluorescence Emitters

Thermally activated delayed fluorescence (TADF) emitters potentially can provide organic light‐emitting diodes with 100% internal quantum efficiency by harvesting triplet excitons. Generally, TADF emitters are small molecules that are not applicable for solution processability. The addition of tert‐butyl groups to the periphery of TADF emitters has proven to improve their solubility in various organic solvents, reduce aggregation‐induced quenching, and enhance the photoluminescence quantum yield (PLQY). This article studies the photophysical influence of the tert‐butyl group attached to an emitter with a carbazole acceptor and a triazine donor. The resulting t3CzTrz‐F is a blue–green TADF emitter, in which the addition of a tert‐butyl group increases the rate of reverse intersystem crossing (rISC), while simultaneously decreasing the nonradiative decay rate substantially. In addition, dilution of t3CzTrz‐F in a host matrix in film results in an enhanced PLQY, which is associated with a decrease in the nonradiative decay constant, while there is no change in the rISC rate. Through a solid‐state NMR study, the change in rISC and nonradiative rate upon tert‐butylation by enlarged intermolecular spacing and reduced vibrational and rotational freedom is rationalized, resulting in improved photophysical performance.