CRYSTENGCOMM
·
2025
·Vol. 27
·期 18
·2920-2930
·
IF 2.6
Haoxin Hu,Shizhao Ren,Feiting Gan,Rongrong Xue,Fenghua Chen
Hypoxanthine is an important component in guanine biominerals, and its polymorphs and morphology controls are rarely reported. In this work, three polymorphs of hypoxanthine were obtained by a solvent evaporation method: form I (triclinic) from an aqueous solution, form II (monoclinic) from an ethanol solution, and form III (a newly proposed polymorph but not observed first) from an ammonia solution. Solubility measurements in water and ethanol indicated that the stability order of the three polymorphs of hypoxanthine was form I > form III > form II. The Raman, IR and 13C ss-NMR spectra indicated that the crystal structures of forms I and III were similar but different from that of form II. The formation of form II was related to the hypoxanthine assemblies in ethanol, as demonstrated by UV spectroscopy. The PXRD patterns and SEM images showed that the three polymorphs had different growth behaviors, as revealed by comparing the hydrogen-bonding planes and π–π stacking modes. Form I had a flat hydrogen-bonding plane with non-vertical π–π stacking, benefitting v∥hydrogen-bonding, while form II had a wavy hydrogen-bonding plane with vertical π–π stacking, benefitting from v∥π–π stacking. The polymorph and morphology controls of hypoxanthine can extend the understanding of the principles of organic biomineralization based on guanine biominerals.
研究领域:
化学
·
生物矿化
·
材料科学
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产品关联
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2022
·
IF 4.01
Xiao Ou,Shuting Li,Yunyun Chen,Haowei Rong,Ao Li,Ming Lu
Griseofulvin (GSF) is a clinically used antifungal drug that was reported to have three true polymorphs (Forms I–III) over the past eight decades. Here, we present the discovery of two new polymorphs (denoted Forms IV and V) that are accessible only in the presence of polyethylene glycol (PEG). The crystal structures of Forms IV and V were determined by X-ray crystallography using single crystals cultivated by melt crystallization. The identification and crystallization behavior of Forms IV and V were fully investigated. A solid-form landscape of melt-crystallized GSF in the presence of PEG was established to describe the complicated phase conversions among six solid forms, including five true polymorphs and a previously known GSF-PEG inclusion complex. The influence of the molecular weight and content of PEG on the polymorphism of GSF was studied. This work suggests that PEG addition is an alternative strategy that cannot be neglected in polymorphism screening. The results also expand our understanding of the complicated crystallization behavior of GSF in dispersions with PEG and highlight the importance of polymorphism control during the manufacture and storage of PEG-based solid dispersions to achieve reproducible and consistent pharmaceutical performance.
研究领域:
药学
·
晶体化学
·
材料科学
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2014
·Vol. 16
·期 28
·6450-6458
·
IF 3.858
Song Li,Jia-Mei Chen,Tong-Bu Lu
Although polymorphism is a common phenomenon, the polymorphism of co-crystals is not studied extensively as compared to single-component molecules. Herein we report polymorphism in a co-crystal system comprising 5-fluorouracil, and 4-hydroxybenzoic acid with a 1 : 1 stoichiometry. The polymorphs were characterized by single-crystal and powder X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis. Crystal structure analysis revealed different synthons of 5-fluorouracil and 4-hydroxybenzoic acid in two forms. The solvent-drop grinding experiments show a high degree of solvent polarity specificity. The theoretical and experimental methods suggest an enantiotropic relationship between the polymorphs.
研究领域:
药物化学
·
晶体学
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产品关联
DOI
高影响因子
Foods
·
2022
·Vol. 11
·期 22
·3592
·
IF 5.561
Houbin Gao,Wei Gao,Xiaomin Yang,Yuanfa Liu,Zhouping Wang
The malleability of Industrial Sheet Margarine (ISM) is essential for the formation of consistent layered structures of pastry products. However, there is limited reporting on how to improve the malleability of ISM with zero trans fatty acids (TFA) at an industrial production scale. Therefore, herein, Shea Olein (SHOL), rich in stearic acid C18:0, was employed as a value-added formulation ingredient to replace palm olein (POL) in palm-based formula (palm stearin:palm kernel olein:palm olein, 50:15:35,w/w/w) and the chemical interesterification (CIE) fat as ISM material was performed to improve the application performance. The addition of SHOL improved the crystallization characteristics by increasing the β’ crystal content from 70.86% to 92.29% compared with a POL-added formula. The hardness of the two formulations after CIE decreased by 60% and 65%, respectively, compared with that before CIE due to the decrease of PPP and POP, and the increase of POS and PSS triacylglycerols. Melting profiles, polymorphism, and crystal structures systematically proved the bending and sheeting features and functional properties. The bending abilities and malleability of ISM with SHOL and CIE fats were significantly improved, resulting in a more conducive application performance. The study provided a practical approach to improving the malleability of ISM in industrial-level production.Keywords:industrial sheet margarine;malleability;polymorphism;shea olein;interesterification
研究领域:
食品科学
·
化学工程
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产品关联
DOI
PubMed
高影响因子
ACS Applied Energy Materials
·
2021
·
IF 6.024
Wanxing Zhang,Peixing Shen,Lizhi Qian,Yuan Wang,Hamidreza Arandiyan,Hitham Mahmoud,Xuemei Liu,Jun Wang,Xiaoliang Wang,Yanguo Liu,Hongyu Sun,Yanlong Yu
Niobium pentoxide (Nb2O5) material is a promising anode for lithium-ion batteries (LIBs) due to the outstanding cycle performance and rate capability. However, the relatively low capacity severely limits the comprehensive performance. Generally, nanoscale engineering of the morphology and chemical composition of Nb2O5 anodes is employed to improve electrochemical lithium storage. In this work, we promote the reservable capacity of a sheetlike Nb2O5 anode by designing nanoscale phase interfaces between the nanodomains of T-Nb2O5, M-Nb2O5, and H-Nb2O5 phases, which are generated by good control over the calcination of Nb3O7F precursor at high temperatures. Microstructural and chemical analyses show that the sample calcined at 750 °C (Nb2O5-750) has optimized structural advantages to efficiently store lithium ions. When evaluated as anodes for LIBs, the Nb2O5-750 sample shows excellent lithium storage properties. In specific, the Nb2O5-750 electrode delivers a reversible capacity of 270.4 mAh g–1 at 1C after 200 cycles. At a high rate of 5C, the Nb2O5-750 electrode has a reversible capacity of 174 mAh g–1 after 800 cycles. This work provides an alternative way to improve the ion storage in the electrodes with intrinsic polymorphic structures.
研究领域:
材料科学
·
电化学
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DOI
高影响因子
Catalysis Science & Technology
·
2016
·Vol. 6
·期 22
·7967-7975
·
IF 5.287
Jie Zhao,Yun Wang,Yingxuan Li,Xiu Yue,Chuanyi Wang
CeO2 is a basic promoter for CO2 photoreduction with H2O over TiO2-based catalysts, but there is still a lack of insight into the interaction of CeO2 with different TiO2 polymorphs and its effect on CO2 photoreduction. In this study, pure anatase, brookite, and rutile TiO2 and their respective hybrids with CeO2 were prepared, and their structural properties, optical properties, interfacial interaction and activity for CO2 photoreduction were systematically studied. The addition of CeO2 improved the activity for CO2 photoreduction under simulated sunlight irradiation, but the improvement depends on the phases of the TiO2. X-ray diffraction, macro-Raman spectroscopic and electron paramagnetic resonance measurements confirm the presence of Ti defects at the CeO2–rutile interfaces, implying a relatively strong interaction between CeO2 and rutile, which is beneficial for the interfacial separation of photogenerated charge carriers. As a result, CeO2/rutile shows the best enhancement of CO2 photoreduction among the studied CeO2/TiO2 systems. Moreover, different paramagnetic species were detected in the three TiO2 polymorphs. The O− radical anion in the anatase lattice could be oxidized to produce Ti3+ under UV-light irradiation, whereas the O2− radical anion on the surface of brookite TiO2 might retard CO production.
研究领域:
材料科学
·
催化化学
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DOI
高影响因子
Chemical Science
·
2020
·Vol. 11
·期 16
·4065-4073
·
IF 9.346
Yulian Liu,Kerong Deng,Jun Yang,Xiaotong Wu,Xiaokun Fan,Min Tang,Zewei Quan
Self-assembly of colloidal nanoparticles into ordered superstructures provides a promising route to create novel/enhanced functional materials. Much progress has been made in self-assembly of anisotropic nanoparticles, but the complexity and tunability of superstructures remain restricted by their available geometries. Here we report the controlled packing of nanodumbbells (NDs) with two spherical lobes connected by one rod-like middle bar into varied superstructure polymorphs. When assembled into two-dimensional (2D) monolayer assemblies, such NDs with specific shape parameters could form orientationally ordered degenerate crystals with a 6-fold symmetry, in which these NDs possess no translational order but three allowed orientations with a rotational symmetry of 120 degrees. Detailed analyses identify the distinct roles of subunits in the ND assembly: the spherical lobes direct NDs to closely assemble together into a hexagonal pattern, and the rod-like connection between the lobes endows NDs with this specific orientational order. Such intralayer assembly features are well maintained in the two-layer superstructures of NDs; however, the interlayer stackings could be adjusted to produce stable bilayer superstructures and a series of metastable moiré patterns. Moreover, in addition to horizontal alignment, these NDs could gradually stand up to form tilted or even vertical packing based on the delicate control over the liquid–liquid interface and ND dimensions. This study provides novel insights into creating superstructures by controlling geometric features of nanoscale building blocks and may spur their novel applications.
研究领域:
材料科学
·
纳米技术
·
化学工程
✓ 已验证
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2025
·
IF 3.4
Zhonghua Li,Songgu Wu,Junbo Gong
The influence of halogen-atom substitution for a dimethyl isophthalate compound on the polymorphic behavior and isostructurality property was explored in this paper. Sublimation was demonstrated to exhibit remarkable advantages. Specifically, two polymorphs (Form I and Form II) of dimethyl 5-bromoisophthalate and two polymorphs (Form A and Form B) of dimethyl 5-iodoisophthalate were discovered for the first time. Moreover, the corresponding single crystals suitable for crystal structure determination were also successfully harvested within a few hours. More interestingly, the crystal packing similarities between the stable Form II and metastable Form A were established with the evaluation of quantitative analysis tools. The success in achieving the regulation of luminescence emission with the changes of crystal packing patterns, molecular conformations, and interactions via halogen substitution will provide some inspiration for the development of novel flexible optical solid-state systems in the future.
研究领域:
材料科学
·
晶体学
✓ 已验证
DOI
高影响因子
PHYSICS LETTERS A
·
2024
·
IF 2.3
Ting-ting Yan,Ran Jiang,Dong-yang Xi,Long Ma,Dan-dan Zhang,Yi-fei Xu
This study investigated the structural stability of 1-methylhydantoin (1-MH, C 4 H 6 N 2 O 2 ) Form-I at room temperature using Raman spectroscopy and a diamond anvil cell (DAC) for high-pressure experiments. Two phase transitions were identified at pressures of 0.6–1.7 GPa and 3.4–6.7 GPa. After complete release of pressure, the spectrum aligned with the Raman spectrum at ambient pressure, indicating reversibility of the phase transition. Analysis of Hirshfeld surface energy and fingerprints was conducted to assess changes in intermolecular interactions, revealing that the phase transitions are associated with rearrangements in the hydrogen-bonded network.
研究领域:
物理化学
·
材料科学
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DOI
高影响因子
MOLECULAR PHARMACEUTICS
·
2024
·
IF 4.5
Fanfan Fan,Yi Lu,Shuyuan Xu,Minshan Guo,Ting Cai
Metastable polymorphs of active pharmaceutical ingredients can occasionally be used to enhance bioavailability or make processing more convenient. However, the thermodynamic instability of metastable polymorphs poses a severe threat to the quality and performance of the drug products. In this study, we used hot-stage microscopy and powder X-ray diffraction to quantitatively analyze the kinetics of the solid–solid phase transition of piracetam (PCM) polymorphs in the absence and presence of several polymeric excipients. The Forms I and II of PCM are enantiotropically related polymorphs, and the transition point is 75 °C. We found that 1 wt % polymer can strongly affect the transformation rate of Form II to Form I of PCM above 75 °C. PVP K30 has the highest Tg and the strongest inhibitory effect on the transition, whereas PEG has the lowest Tg and the weakest effect on the transition. Below 75 °C, the addition of 1 wt % PEG can decrease the transformation rate from Form I to Form II of PCM by a few orders of magnitude, whereas no phase transition occurs in the presence of the other investigated polymers. The inhibitory effects of the same concentration of polymers on the kinetics of the solid–solid phase transition of piracetam polymorphs are considerably greater than those on the crystallization of PCM from the amorphous phase, especially at low temperatures. We propose that the low segmental mobility of polymers enriched between the crystalline phases can considerably inhibit the nucleation and growth of the stable form at the interface during the phase transition. Our findings deepen the current understanding of the mechanisms underlying the solid-state phase transition of polymorphic drugs in the presence of polymeric excipients, providing a promising formulation approach for stabilizing the metastable pharmaceutical polymorphs.
研究领域:
药剂学
·
材料科学
·
药物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ULTRASONICS SONOCHEMISTRY
·
2021
·
IF 7.491
Chen Fang,Peng Yang,Yumin Liu,Jingkang Wang,Zhenguo Gao,Junbo Gong,Sohrab Rohani
In this paper, the ultrasound-assisted solvent-mediated polymorphic transformation of theophylline was explored in detail. The induction time and reconstruction time were significantly decreased by ultrasound, thereby decreasing the total transformation time and promoting the transformation process. The ultrasound-promoted efficiency of nucleation was different in three alcoholic solvents, which was difficult to explain by traditional kinetic effects. To resolve the above confusion, binding energies calculated by Density Functional Theory were applied to explore the relationship between the ultrasound-promoted efficiency of nucleation and solute–solvent interactions. Then, a possible molecular self-assembly nucleation pathway affected by ultrasound was proposed: the ultrasound could change and magnify the crucial effect of the specific sites of solute–solvent interactions in the nucleation process. Finally, the transformation kinetics with different effective ultrasonic energies was quantitatively analyzed by Avrami-Erofeev model, indicating that the dissolution element in the rate-limiting step was gradually eliminated by higher ultrasonic energy. Fortunately, the elusive crystal form V could be easily obtained by the ultrasound-assisted polymorph transformation. This proved to be a robust method to produce high purity form V of theophylline. The outcome of this study demonstrated that the proper ultrasonic irradiation had the potential to produce specific polymorphs selectively.
研究领域:
药剂学
·
物理化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CRYSTENGCOMM
·
2021
·Vol. 24
·期 4
·854-862
·
IF 3.545
Xiunan Zhang,Jingkang Wang,Fei Yu,Xiaowei Cheng,Yunhui Hao,Yue Liu,Xin Huang,Ting Wang,Hongxun Hao
Development of polymorphism-dependent organic fluorescent crystals through polymorphic manipulation with additives could be a potential strategy for making new materials with different functions and properties. In this work, three polymorphs of an X-shaped tetrasubstituted molecule, 2,5-bis(5-methyl-2-thienyl) terephthalaldehyde, were successfully manipulated using additives. Distinct photophysical properties between Form I (530 nm) and Form II (570 nm) were observed, which could provide a potential method for intuitively observing the polymorphic transformation and nucleation of different polymorphic forms. With the incorporation of NMR titration, computational simulation and X-ray crystallographic analysis, the mechanism of additive-induced polymorphism was carefully investigated. Different crystallization experimental results suggest that additives could inhibit the formation of Form I while promoting the formation of Form II.
研究领域:
材料科学
·
化学
·
晶体学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）