Solid-state Properties Research Articles

Solid-State Reversible Phase Transition and Photoluminescence Properties of Organic-Inorganic Hybrid Halide: (BTPA)2MnBr4.

Multifunctional materials have long been a popular research area, with organic-inorganic hybrids frequently utilized due to their diverse properties and versatile assembly techniques. In this context, a novel Mn-based organic-inorganic hybrid compound (BTPA)2MnBr4(1) was prepared, with strong green photoluminescence, phase transition under thermal stimulation, and two reversible dielectric-state switches. This compound exhibits strong green photoluminescence under ultraviolet excitation, boasting a quantum yield of 44.36%. Furthermore, it demonstrates a reversible ferroelastic phase transition at 358/348 K. The integration of temperature and photosensitivity in compound 1 opens up new avenues for the development and exploration of a broader spectrum of multifunctional phase transition materials.

Star-Shaped Polymers with Helical Polyacetylene Arms. Comparison of Solution- and Solid-State Properties with Linear Helical Polyacetylenes

Star-Shaped Polymers with Helical Polyacetylene Arms. Comparison of Solution- and Solid-State Properties with Linear Helical Polyacetylenes

Novel high-temperature thermochromic polydiacetylene material and its application as thermal indicator

The design and synthesis of organic high-temperature reversible thermochromic materials is one of the difficult issues in the field of organic chromic materials. In this paper, four diacetylene monomers named DBA-PCDA, TBA-PCDA, DBE-PCDA and TBE-PCDA, each containing multiple diacetylene units, were synthesized from 10,12-pentacosadiynoic acid (PCDA) through the amidation or esterification reactions, using 4,4′-diaminobiphenyl, 1,3,5-tris(4-aminophenyl)benzene, 4,4′-dihydroxybiphenyl, and 1,3,5-tris(4-hydroxyphenyl)benzene as bridging units. The effects of functional groups that can form hydrogen bond and π-π interactions on the solid-state polymerization properties of monomers and the thermochromic properties of the corresponding PDAs were investigated. The results show that only DBA-PCDA and TBA-PCDA, which contain functional groups that can form hydrogen bonding interactions, can be polymerized under 254-nm UV irradiation. The corresponding poly(DBA-PCDA) exhibits reversible thermochromic property even heated up to 200 oC, showing a potential application in the field of high-temperature thermal indicator above 100 °C. This work provides a new perspective to the development of PDA with high-temperature reversible thermochromic property.

Creation of Excitation-Driven Hypervalent Tin(IV) Compounds For Aggregation-Induced Emission and Application to Thermoresponsive Luminescent Films Below Freezing Point.

Although many researchers have devoted their much effort to establish the strategy for developing a stimuli-responsive molecule and tuning of their properties according to the preprogrammed design, it is still challenging to create desired molecules from the scratch. We recently demonstrated that the molecules with a large structural difference between the theoretically optimized structures in the ground and excited states have a potential to exhibit stimuli-responsive luminescent properties. We defined these molecules as an excitation-driven molecule and have shown that they are a versatile platform for designing stimuli-responsive luminescent molecules. Herein, based on the concept of excitation-driven molecules, we show that the hypervalent tin-fused azomethine (TAm) compounds possessing aggregation-induced emission (AIE) properties can be obtained by simple chemical modification with a methyl group although conventional TAm derivatives are well known to be highly luminescent compounds in solution. Furthermore, by combining the solid-state luminescence property of AIE and the coordination number shifts of the hypervalent tin atom, the thermoresponsive films operating below the freezing point are fabricated with the polymer. In this study, we apply the concept of excitation-driven molecules to the hypervalent compounds and demonstrate to obtain the novel functional materials.

Encasing Triaryltriazine with a Bulky Chiral Cap: Luminescent Chiral Crystalline Molecular Rotors with Modulation of Solid-State Chiroptical Properties Mediated by Molecular Rotation.

A novel structural motif for luminescent chiral crystalline molecular rotors with chiroptical properties correlated with the rotational motion in crystalline media is presented. This scaffold incorporates bulky chiral caps consisting of a homochiral binaphthyl moiety with a triisopropylsilyl (TIPS) group into triaryltriazine, as confirmed by single-crystal X-ray diffraction (XRD) analysis. Variable-temperature solid-state 2H NMR studies revealed a 4-fold rotation of the phenylenes occurred in the rotor crystal between 263 and 333 K, while a steric rotor analogue shows no rotational motion. Notably, a reduction in the dihedral angle of the binaphthyl moiety upon heating was observed in the chiral rotors, and a corresponding alteration of the circular dichroism (CD) signal was detected in the solid-state, while those of the steric rotors showed no alteration by the temperature change. We propose that the fast rotation of the phenyl rings affects the motion of neighboring isopropyl groups, leading to steric repulsion with the binaphthyl moieties and thereby inducing its conformational change. Furthermore, the chiral rotors exhibited circularly polarized phosphorescence in the solid-state at low temperature, originating from rotational displacement of the phenylene on triphenyltriazine during structural relaxation in the excited state. Meanwhile, the steric rotors showed significant circularly polarized fluorescence induced by the suppressed molecular motion via a sterically hindered lattice environment in the excited state. These results indicate that the bulky chiral cap introduced into the triaryltriazines, acting as a luminescent chiral crystalline molecular rotor, can be a useful scaffold for the modulation of solid-state chiroptical properties via molecular rotational motions.

Development of Predictive Statistical Model for Gaining Valuable Insights in Pharmaceutical Product Recalls.

The rapid progress in artificial intelligence (AI) has revolutionized problem-solving across various domains. The global challenge of pharmaceutical product recalls imposes the development of effective tools to control and reduce shortage of pharmaceutical products and help avoid such recalls. This study employs AI, specifically machine learning (MI), to analyze critical factors influencing formulation, manufacturing, and formulation complexity which could offer promising avenue for optimizing drug development processes. Utilizing FDAZilla and SafeRX tools, an open database model was constructed, and predictive statistical models were developed using Multivariate Analysis and the Least Absolute Shrinkage and Selection Operator (LASSO) Approach. The study focuses on key descriptors such as delivery route, dosage form, dose, BCS classification, solid-state and physicochemical properties, release type, half-life, and manufacturing complexity. Through statistical analysis, a data simplification process identifies critical descriptors, assigning risk numbers and computing a cumulative risk number to assess product complexity and recall likelihood. Partial Least Square Regression and the LASSO approach established quantitative relationships between key descriptors and cumulative risk numbers. Results have identified key descriptors; BCS Class I, dose number, release profile, and drug half-life influencing product recall risk. The LASSO model further confirms these identified descriptors with 71% accuracy. In conclusion, the study presents a holistic AI and machine learning approach for evaluating and forecasting pharmaceutical product recalls, underscoring the importance of descriptors, formulation complexity, and manufacturing processes in mitigating risks associated with product quality.

Solid-State Structures and Properties of Lignin Hydrogenolysis Oil Compounds: Shedding a Unique Light on Lignin Valorization

This article explores the important, and yet often overlooked, solid-state structures of selected bioaromatic compounds commonly found in lignin hydrogenolysis oil, a renewable bio-oil that holds great promise to substitute fossil-based aromatic molecules in a wide range of chemical and material industrial applications. At first, single-crystal X-ray diffraction (SCXRD) was applied to the lignin model compounds, dihydroconiferyl alcohol, propyl guaiacol, and eugenol dimers, in order to elucidate the fundamental molecular interactions present in such small lignin-derived polyols. Then, considering the potential use of these lignin-derived molecules as building blocks for polymer applications, structural analysis was also performed for two chemically modified model compounds, i.e., the methylene-bridging propyl-guaiacol dimer and propyl guaiacol and eugenol glycidyl ethers, which can be used as precursors in phenolic and epoxy resins, respectively, thus providing additional information on how the molecular packing is altered following chemical modifications. In addition to the expected H-bonding interactions, other interactions such as π–π stacking and C–H∙∙∙π were observed. This resulted in unexpected trends in the tendencies towards the crystallization of lignin compounds. This was further explored with the aid of DSC analysis and CLP intermolecular energy calculations, where the relationship between the major interactions observed in all the SCXRD solid-state structures and their physico-chemical properties were evaluated alongside other non-crystallizable lignin model compounds. Beyond lignin model compounds, our findings could also provide important insights into the solid-state structure and the molecular organization of more complex lignin fragments, paving the way to the more efficient design of lignin-based materials with improved properties for industrial applications or improving downstream processing of lignin oils in biorefining processes, such as in enhancing the separation and isolation of specific bioaromatic compounds).

The broad-spectrum biocide triclosan trigonal crystal: Experimental and DFT-calculated structural, electronic and optical properties

Triclosan, a member of the broad-spectrum biocide class, has seen widespread usage in various household and healthcare-related products worldwide over the past 35 years. However, its extensive use has raised concerns regarding health and environmental impacts. Notably, there is a notable gap in our understanding of the solid-state properties of triclosan, encompassing both experimental aspects, such as optical absorption, and theoretical insights. Expanding upon the established trigonal crystal structure of triclosan, this study employs experimental techniques including X-ray and photoacoustic-based optical absorption, alongside density functional theory (DFT) calculations, to elucidate its structural, electronic, and optical characteristics. Employing the generalized gradient approximation (GGA) DFT exchange-correlation functional and accounting for dispersion effects, optimal lattice parameters were determined with small deviations from experimental measurements (<∼2.2%). The calculations predict that the triclosan trigonal crystal has very close direct band gaps of about 3.44 eV, almost identical to the value of 3.45 eV derived from photoacoustic optical absorption measurements. Analysis of the calculated optical absorption and complex dielectric function underscores the optical isotropy of solid state triclosan. Furthermore, effective mass computations, in conjunction with the band gap results, suggest that triclosan displays electronic characteristics akin to those of a wide direct gap semiconductor.

Spin-reorientation transition and exchange-bias effect in CeFe0.5Cr0.5O3 ceramics

The polycrystalline CeFe0.5Cr0.5O3 ceramics were synthesized by the solid-state method, whose structural and magnetic properties were systematically studied. With the interaction between Ce and Fe/Cr ions, a first-order spin-reorientation transition from Γ4 to Γ1 is observed over a wide temperature interval in CeFe0.5Cr0.5O3, which is remarkably sensitive to applied magnetic field. Interestingly, the exchange-bias effect is found in CeFe0.5Cr0.5O3 ceramics during the spin-reorientation transition, ascribed to the paramagnetic/antiferromagnetic system presented by the two interacting magnetic sublattices (Ce and Fe/Cr). The coexistence of spin-reorientation transition and exchange-bias effect is promising to expand the practical application of CeFe0.5Cr0.5O3 ceramics in multifunctional spintronics.

Exploring vacuum foam drying as an alternative to freeze-drying and spray drying for a human lipase

This article compares and explores vacuum foam-drying as an alternative drying technology to freeze-drying and spray drying for a recombinant human lipase as the model protein. Materials characteristics such as structure, surface composition and the solid-state properties of the dry materials were compared and investigated. Moreover, the technical functionality in terms of reconstitution characteristics and the lipase stability were also investigated. The stability of the lipase was evaluated through activity measurements. Sucrose and dextran D40 (40 kDa) were used as matrix former and the surfactant α-dodecyl maltoside was used as surface active additive. The study demonstrated that the drying technique greatly influenced the material structure and composition which in turn affected the reconstitution characteristics. The lipase was overrepresented at the material surface in declining order spray-dried > vacuum foam-dried > freeze-dried. The lipase activity was retained up to 10 % lipase content in solids, but at 20 % lipase a loss of activity was observed for all drying techniques. Phase separation in the solid material may be an explanation. Vacuum foam-drying shows promise as an alternative drying technique for the lipase, and potentially other proteins.

Synthesis of polyfumarates containing a 4-tert-butylcyclohexyl group and unique solid-state properties based on the orientation of rigid poly(substituted methylene) chains

Synthesis of polyfumarates containing a 4-tert-butylcyclohexyl group and unique solid-state properties based on the orientation of rigid poly(substituted methylene) chains

On the importance of crystal structures for organic thin film transistors.

Historically, knowledge of the molecular packing within the crystal structures of organic semiconductors has been instrumental in understanding their solid-state electronic properties. Nowadays, crystal structures are thus becoming increasingly important for enabling engineering properties, understanding polymorphism in bulk and in thin films, exploring dynamics and elucidating phase-transition mechanisms. This review article introduces the most salient and recent results of the field.

Synchrotron radiation Fourier-transform infrared absorption measurements on the single-crystal dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene

The strong coupling of charge carriers with molecular vibrations is one essential characteristic of organic semiconductor materials as molecular solids. To address this question, fundamental solid-state properties of each molecular species are demanded not only for the electronic states but also for the vibrational characteristics. In the present study, Fourier-transform infrared absorption measurements were performed on single-crystal samples of dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) by using a linearly polarized synchrotron radiation light source. Molecular vibrational modes in a wavenumber range of 200–1600 cm−1 were reasonably assigned, and the Davydov splittings of several vibrational modes were resolved demonstrating intermolecular couplings of two DNTT molecules in the unit cell.

Thermally stable strongly fluorescent multi-stimuli responsive carbazole zwitterionic fluorophores: Alkyl chain length dependent thermofluorochromism and latent fingerprinting

Carbazole-picoline based π-conjugated zwitterionic fluorophores, (E)-3-(4-(4-(9H-carbazol-9-yl)styryl)pyridin-1-ium-1-yl)propane-1-sulfonate (Cz-PS) and (E)-4-(4-(4-(9H-carbazol-9-yl)styryl)pyridin-1-ium-1-yl)butane-1-sulfonate (Cz-BS) were synthesized and investigated the stimuli-responsive solid-state fluorescence properties. Cz-PS and Cz-BS displayed enhanced fluorescence in the solid-state (555 and 542 nm) with the quantum yield (Φf) of 32.9 and 28.5 %, respectively. Thermogravimetric analysis (TGA) indicated good thermal stability up to 300 °C for both Cz-PS and Cz-BS. Single crystal structural analysis of Cz-BS confirmed twisted molecular conformation and supramolecular interactions induced network structure, which lead to increase of solid-state fluorescence. Cz-BS showed mechanical stimuli-induced reversible/self-reversible fluorescence switching between two fluorescence states whereas Cz-PS did not show mechanofluorochromism. But both Cz-PS and Cz-BS showed acid/base dependent on–off reversible fluorescence switching in solution as well as solid-state. Further, both compounds also displayed reversible thermofluorochromism by heating and cooling. The yellow fluorescence of Cz-PS and Cz-BS was transformed to orange upon heating at 110 °C and cooling reversed the fluorescence to initial state. The good thermal stability and enhanced solid-state fluorescence of Cz-PS and Cz-BS were utilized for latent fingerprinting (LFP) application on various solid substrate. Particularly, LFP images of Cz-BS showed finger marks with well-defined features. Thus, integrating zwitterionic functionality produced strong solid-state fluorescence with multi-functional applications.

The effects of raw materials particle sizes on the solid-state reaction progress, morphology and magnetic properties of M-type strontium hexaferrites

In this work, the effects of SrCO3 and Fe2O3 particle size on the reaction process, morphology and magnetic properties of M-type strontium hexaferrites (SrM) have been further studied. Pure strontium hexaferrite magnetic sample based on SrCO3 and Fe2O3 molar ratio of 1:6 has been successfully prepared at 1150 °C. The results indicated that Fe2O3 particle size was the main factor of affecting the formation of SrM, a pure SrM phase magnetic sample was able to obtain at lower calcination temperatures by using fine Fe2O3 powder as raw material, and at the same calcination temperature, a sample using fine Fe2O3 powder as raw material was able to obtain pure SrM phase magnetic sample with shorter holding time. When the mean particle size of Fe2O3 was below 60 nm, a pure SrM phase magnetic sample was able to form at 1150 °C at a molar ratio of 1:6 of SrCO3 and Fe2O3. In this case, the magnetic parameters of the sample with the optimum magnetic parameters were saturation magnetization MS = 77.8 emu/g and coercive force HC = 4122 Oe. And the solid-state reaction process of the corresponding samples was slightly faster when the mean particle size ratio of Fe2O3 and SrCO3 was between 0.35 and 0.36. Assuming that a SrCO3 particle is surrounded by Fe2O3 particles, it can be inferred that the corresponding molar ratio of Fe and Sr of the nearest raw material particles is between 3.6 and 3.8.

Enabling room temperature solid-state lithium batteries by blends of copolymers and ionic liquid electrolytes

High lithium-concentration phosphonium ionic liquids electrolytes have shown outstanding properties even overcoming ammonium derivatives in terms of viscosity and transport properties. Consequently, they have been also combined with fluorinated polymers, such as poly(vinylidene fluoride) (PVDF) or poly(ionic liquids), for solid-state batteries with satisfying performance at 50 °C. The aim of this work is to develop highly lithium conducting solid-state electrolyte (≥0.1 mS cm−1) at room temperature but maintaining solid-state properties. For this, polymer electrolytes based on ISOBAM alternating copolymer (isobutylene and maleic anhydride) and ionic liquid (P111i4FSI) were developed. The composition-dependent behavior of the solid electrolytes was studied in terms of electrochemical impedance spectroscopy (EIS), reaching σLi+ of 0.52 mS cm−1; differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR) under different ionic liquid electrolyte loadings and salt concentration. The polymer electrolytes presented a solid-like behavior in the range of 25 to 90 °C with a storage modulus of 2.3·104 Pa. Finally, the best free-standing membrane electrolytes were tested and compared electrochemically in lithium symmetrical cells and lithium iron phosphate full cells exhibiting an excellent cycling at room temperature.

Pillar[5]arene-Based Ion-Pair Recognition for Encapsulation of a Stilbazolium-Type Dye with Enhanced Photophysical Properties and Nonlinear Optical Activity.

Constructing organic composite materials through molecular recognition has emerged as an important theme in materials science. Here we report an ion-pair recognition system involving the use of a propoxylated pillar[5]arene (PrP5) to modulate the solid-state photophysical properties of dye trans-4'-(dimethylamino)-N-methyl-4-stilbazolium hexafluorophosphate (DMASP). Single crystal X-ray diffraction analysis reveals that the dye guest DMASP is encapsulated by PrP5 to form a 2 : 1 host-guest complex 2PrP5⸧DMASP in the crystalline state. The macrocyclic skeleton of PrP5 imposes restrictions on the intramolecular motions of the dye guest, leading to a significant enhancement of its fluorescence emission. Additionally, within the 2PrP5⸧DMASP complex crystal structure, DMASP molecules are found to display two possible opposite orientations in the one-dimensional channels formed by PrP5 molecules. This arrangement is believed to alter the overall solid-state packing structure of DMASP, thereby activating its nonlinear optical activity. This work not only reports a novel ion-pair molecular recognition system based on pillararenes but also provides valuable insights into the modulation of the crystalline state photophysical properties of organic dyes via cocrystal engineering.

Development of Orodispersible Tablets with Solid Dispersions of Fenofibrate and Co-Processed Mesoporous Silica for Improved Dissolution.

Poor water solubility is an important challenge in the development of oral patient-friendly solid dosage forms. This study aimed to prepare orodispersible tablets with solid dispersions of a poorly water-soluble drug fenofibrate and a co-processed excipient consisting of mesoporous silica and isomalt. This co-processed excipient, developed in a previous study, exhibited improved flow and compression properties compared to pure silica while maintaining a high specific surface area for drug adsorption. Rotary evaporation was used to formulate solid dispersions with different amounts of fenofibrate, which were evaluated for solid state properties and drug release. The solid dispersion with 30% fenofibrate showed no signs of crystallinity and had a significantly improved dissolution rate, making it the optimal sample for formulation or orodispersible tablets. The aim was to produce tablets with minimal amounts of additional excipients while achieving a drug release profile similar to the uncompressed solid dispersion. The compressed formulations met the requirements for orodispersible tablets in terms of disintegration time, and the drug release from best formulation approximated the profile of uncompressed solid dispersion. Future research should focus on reducing the disintegration time and tablet size to enhance patient acceptability further.

Extended benchmark set for lattice parameters of inorganic solids.

The development of novel methods in solid-state quantum chemistry necessitates reliable reference data sets for their assessment. The most fundamental solid-state property of interest is the crystal structure, quantified by the lattice parameters. In the last decade, several studies were conducted to assess theoretical approaches based on the agreement of calculated lattice parameters with respect to experiment as a measure. However, most of these studies used a limited number of reference systems with high symmetry. The present work offers a more comprehensive reference benchmark denoted as Sol337LC, which consists of 337 inorganic compounds with 553 symmetry-inequivalent lattice parameters, representing every element of the periodic table for atomic numbers between 1 and 86, except noble gases, the radioactive elements and lanthanoids. The reference values were taken from earlier benchmarks and from measurements at very low temperature or extrapolation to 0 K. The experimental low-temperature lattice parameters were then corrected for zero-point energy effects via the quasi-harmonic approximation for direct comparison with quantum-chemical optimized structures. A selection of standard density functional approximations was assessed for their deviations from the experimental reference data. The calculations were performed with the crystal orbital program CRYSTAL23, applying optimized atom-centered basis sets of triple-zeta plus polarization quality. The SCAN functional family and the global hybrid functional PW1PW, augmented with the D3 dispersion correction, were found to provide closest agreement with the Sol337LC reference data.

Electron transport through two interacting channels in Azurin-based solid-state junctions

The fundamental question of "what is the transport path of electrons through proteins?" initially introduced while studying long-range electron transfer between localized redox centers in proteins in vivo is also highly relevant to the transport properties of solid-state, dry metal-protein-metal junctions. Here, we report conductance measurements of such junctions, Au-(Azurin monolayer ensemble)-Bismuth (Bi) ones, with well-defined nanopore geometry and ~103 proteins/pore. Our results can be understood as follows. (1) Transport is via two interacting conducting channels, characterized by different spatial and time scales. The slow and spatially localized channel is associated with the Cu center of Azurin and the fast delocalized one with the protein's polypeptide matrix. Transport via the slow channel is by a sequential (noncoherent) process and in the second one by direct, off-resonant tunneling. (2) The two channels are capacitively coupled. Thus, with a change in charge occupation of the weakly coupled (metal center) channel, the broad energy level manifold, responsible for off-resonance tunneling, shifts, relative to the electrodes' Fermi levels. In this process, the off-resonance (fast) channel dominates transport, and the slow (redox) channel, while contributing only negligibly directly, significantly affects transport by intramolecular gating.