RSC Advances
·
2017
·Vol. 7
·期 18
·10737-10747
·
IF 3.108
Jian Sui,Shi Qi Zhang,Min Zhai,Fang Tian,Jian Zhang,Xiao Zheng Lan
Inspired by the interest in the confinement effect on polymorphism of alkane mixtures, phase behaviors of a hexadecane–heptadecane (n-C16H34–C17H36, C16–C17) binary system in the bulk and in nanopores of controlled porous glasses (CPGs) are investigated using differential scanning calorimetry (DSC) and temperature-dependent powder X-ray diffraction (XRD). As reported, bulk C16–C17 mixtures form two intermediate phases with monoclinic (Mdci) and orthorhombic (Op) structures in a low temperature range and rotator phase RI in high temperature range. In the pores of CPG (300 nm), these solid phases appear in the temperatures slightly below the bulk system. The RI one-phase region extends a bit in temperature range in the mixtures of high C17 components. In CPG (8.1 nm), the solid phases come up in much lower temperatures than the bulk. The rotator RI is found in a larger range of the temperature and composition than the bulk and in CPG (300 nm). A new phase, the rotator RII, is observed in a narrow temperature range of high C17 composition just before melting. XRD analysis shows diffractions from the alkane layered ordering in CPG (300 nm) with a more roughened layer surface than the bulk. Lamellar stacking of the solids in CPG (8.1 nm) is heavily perturbed. The variation in the polymorphism of C16–C17 mixtures in the nanopores is associated with the reduced ordering of the molecule arrangements. These results can help to understand the influence of confinement effect on binary mixtures of alkanes, the chain molecules.
研究领域:
物理化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2019
·
IF 4.153
Yuting Liu,Mingtao Zhang,Danrui Xu,Sean Parkin,Tonglei Li,Conggang Li,Zhaoyong Yang,Faquan Yu,Sihui Long
To probe the effect of substituent size and isomerization on the polymorphism of fenamic acid (FA) derivatives, we synthesized two FA analogues, namely, 2-(naphthalen-1-ylamino)-benzoic acid and 2-(naphthalen-2-ylamino)-benzoic acid (NBAs), and investigated their polymorphism. Contrary to the lack of polymorphism in FA, we discovered two crystal forms (1-I, 1-II, 2-I, and 2-II) for each of the two compounds. We characterized the two polymorphic systems with single-crystal X-ray diffraction, powder X-ray diffraction, and infrared and Raman spectroscopy, and observed certain structural similarities between 1-I and 2-I. The phase behavior of these two systems were studied with differential scanning calorimetry. Computational studies such as the search for stable conformers, lattice-energy calculations, and Hirshfeld surface analysis were performed to shed light on the polymorphism, relative stability of the forms in each system, and contribution of intermolecular interactions to the overall stability of the systems. The study confirmed the effect of substituent size on the polymorphism of the compounds.
研究领域:
化学
·
材料科学
·
药物化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2015
·Vol. 98
·期 8
·2451-2458
·
IF 2.61
Meilu Gong,Fengqi Lu,Xiaojun Kuang,Xiaodi Yu,Quanchao Wang,Xiaohui Li,Liang Fang
Molten salt synthesis (MSS) of the eight-layer hexagonal perovskite Ba 8 NiTa 6 O 24 was performed using mixed KCl–NaCl salts in comparison with solid-state synthesis (SSS). In the SSS, the hexagonal Ba 8 NiTa 6 O 24 formed at 1300°C via a reaction between cubic Ba 3 NiTa 2 O 9 and hexagonal Ba 5 Ta 4 O 15 . While the MSS did not lower the synthesis temperature of the hexagonal Ba 8 NiTa 6 O 24 but stabilized an unusual A- and B-site-deficient cubic perovskite polymorph of Ba 8 NiTa 6 O 24 below 1350°C as an intermediate phase prior to transforming into the hexagonal phase. This cubic polymorph contains ~3% A-site and ~9.5% B-site vacancies plus ~3% Ba cations in the B sites and demonstrated remarkable stability below 1350°C when without presence of the molten salt. The cubic polymorph displayed larger ε ~ 36 and τ f ~ 110 ppm/°C than the hexagonal polymorph from the MSS (ε ~ 29 and τ f ~ 67 ppm/°C). The hexagonal SSS-processed ceramics showed advantageous dielectric properties ( Q f ~ 52 000 GHz, τ f ~ 30 ppm/°C) over both cubic and hexagonal MSS-processed ones ( Q f ~ 18 600–20 000 GHz), while displaying anisotropic grain growth. The anisotropic grain growth was suppressed significantly by the MSS processing.
研究领域:
材料科学
·
陶瓷学
·
固态化学
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2025
·
IF 2.6
Zaixiang Zhang,Xin Li,Junyu Liu,Manman Wang,Yang Yang,Deyin Wang
Four halo-substituted derivatives of salicylideneanilines (4BB, 4BC, 4CB, and 4CC) were prepared and recrystallized in order to investigate the impact of the substitution on the polymorphism of derivatives. Two similar forms, each with a quadrilateral or needle morphology and a yellow or orange color, were observed in all derivatives. The polymorphs' crystal structure and stability were examined. It was discovered that crystals of the same form adopted comparable molecular arrangements in terms of packing style and conformation. According to the DSC pattern and microscopic observations, 4BB, 4CB, and 4CC showed monotropic solid-to-solid transition during the heating process. The contact of seed crystals may also cause a martensitic transformation, in which the transition process is continuous, whereas, the two forms of 4BC crystals can stably exist. In the solution state, comparable transition behavior between polymorphs was observed.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ORGANIC & BIOMOLECULAR CHEMISTRY
·
2019
·Vol. 17
·期 13
·3409-3415
·
IF 3.49
Xinyi Wang,Yifu Chen,Junbo Gong,Jinze Hou
Rare multiple fluorescence properties including aggregation-induced emission and polymorphism/shape/size-dependent emission were found coexisting in a class of typical non-steroidal anti-inflammatory analgesic drugs, fenamates, which could provide a new approach toward future drug evaluation. Different from the complexity and biological incompatibility of the traditional AIE molecular design, this work opens new avenues to the development of new AIE systems.
研究领域:
药理学
·
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CRYSTENGCOMM
·
2017
·Vol. 19
·期 30
·4345-4354
·
IF 3.474
Meng Liu,Chuming Yin,Peng Chen,Mingtao Zhang,Sean Parkin,Panpan Zhou,Tonglei Li,Faquan Yu,Sihui Long
Chlorine can participate in numerous interactions such as halogen bonding, hydrogen bonding, and London dispersion in the solid state. In this work, we report the influence of a chlorine substituent on the polymorphism of a potential anticancer drug, 4-chloro-phenylanthranilic acid (CPAA). Three polymorphs have been discovered for this compound, and the three forms were characterized by single-crystal X-ray diffraction, power X-ray diffraction (PXRD), FT-IR, and Raman spectroscopy. Both conformational flexibility of the molecule and the sp2CH⋯Cl hydrogen bond seem to lead to the polymorphism of the system. The phase behavior was investigated by differential scanning calorimetry (DSC), with the conclusion that form II converts to III upon heating. A conformational scan shows the conformational minima corresponds to the conformers existing in the polymorphs. Lattice energy calculations show energies of −106.70, −104.72, and −194.42 kJ mol−1 for forms I to III, providing information on relative stability for each form. Hirshfeld analysis revealed that intermolecular interactions such as H⋯H, C⋯H, H⋯Cl, and H⋯O contribute to the stability of the crystal forms.
研究领域:
药物化学
·
晶体学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2016
·
IF 3.586
Hai-Mu Ye,Ping Liu,Chun-Xiao Wang,Xiaoyu Meng,Qiong Zhou
Poly(hexamethylene succinate- co -hexamethylene fumarate)s (PHSF) with low hexamethylene fumarate content ( C HF , between 0 and 18 mol%) were prepared and employed to explore the effect of intersegmental interaction in crystalline lattice on the polymorphism phenomenon. Wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) results demonstrate that the crystal modification of PHSF exhibits not only C HF -dependent but also crystallization temperature ( T c ) dependent. Both high C HF and high T c benefit the formation of orthorhombic modification, while low C HF and low T c benefit the formation of monoclinic modification. More intriguingly, the specific “C C C O⋯H C C” hydrogen bonds formed between fumaryl units provide a direct way to regulate the polymorphism from perspective inside chain structure. When C HF is between 8 and 12 mol%, the crystal modification of PHSF is determined by formation of intersegmental hydrogen bonding interaction or not through varying T c . At high T c , the specific hydrogen bonds form and render the formation of orthorhombic crystal; while at low T c , only van der Waals forces remain and PHSF chains crystallize into monoclinic crystal. The content of carbonyl group belonging to fumaryl in polyester chain is a key factor for the formation of hydrogen bonds and the selection of crystal structure during crystallization. Additionally, the orthorhombic crystal shows higher equilibrium melting point than monoclinic crystal; and the monoclinic crystal can transform to orthorhombic crystal by annealing, revealing that orthorhombic crystal is more thermally stable.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2019
·Vol. 25
·期 67
·15401-15410
·
IF 5.16
Gaowei Qian,Xiangbing Wang,Shengyue Wang,Yanqiong Zheng,Song Wang,Weiguo Zhu,Yafei Wang
Graphical Four ′T′-shaped molecules bearing the 2,1,3-benzothiadiazole skeleton were prepared and characterized. All compounds exhibited excellent thermal stability and polymorphism in the solid state. The structure–property relationship of these compounds was systematically explored. A highest external quantum efficiency of 6.15 %, beyond the theoretical value of fluorescence-based OLEDs (∼5 %), were achieved for the solution-processable OLEDs. Polymorphism, the intrinsic character of one chemical compound with at least two distinct phase arrangements, plays a very key role in the photophysical properties. In this contribution, four ′T′-shaped molecules bearing the 2,1,3-benzothiadiazole (BTD) skeleton, named 5 a – 5 d , were prepared and characterized. All compounds exhibited excellent thermal stability and polymorphism in the solid state, evident from thermogravimetric analysis, differential scanning calorimetry, and polarized optical microscopy results. Intense emissions with high photoluminescent quantum yields were achieved both in solution (56–97 %) and neat films (33–98 %). All compounds possessed clearly pH-dependent luminescence properties in solution. Additionally, compound 5 d showed useful mechanochromic luminescence owing to the transformation between the crystal and amorphous state. Employing compounds 5 a – 5 d as the dopant, solution-processable organic light-emitting diodes (OLEDs) were fabricated and presented a highest external quantum efficiency of 6.15 %, which is higher than the theoretical value of fluorescence-based OLEDs (∼5 %). This research provided a novel strategy for designing high-efficiency BTD-based polymorphic luminescent materials.
研究领域:
材料科学
·
光学
·
有机电子学
✓ 已验证
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2023
·
IF 3.8
Yunping Zhoujin,Yuping Li,Peng-Yu Liang,Pan-Pan Zhou,Sean Parkin,Tonglei Li,Faquan Yu,Sihui Long
A series of phenylalkylamino-nicotinic acids (1–4) were synthesized by varying the length of the linker between the pyridine and benzene rings, and their polymorphism was investigated. Under the same crystallization conditions, one crystal form was found for compounds 1 and 2, three forms were obtained for compound 3, and two forms were harvested for compound 4. A detailed conformational analysis was performed, and the polymorphism of 3 and 4 was found to be caused by the anti and/or gauche conformation of specific sigma bonds within them. However, there appears to be no correlation between the number of polymorphs and sigma bonds, and the rotation of which sigma bond(s) is responsible for the polymorphism could not be predicted. Phase behavior studies by differential scanning calorimetry (DSC) revealed a phase transition from 4-I with a small asymmetric unit (Z′ = 1) to 4-II with a larger asymmetric unit (Z′ = 2). Computational studies including Hirshfeld surface analysis and independent gradient model (IGM) analyses were performed to highlight the most significant intermolecular interactions in the crystals.
研究领域:
化学
·
材料科学
·
晶体学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2019
·
IF 2.584
Kai Zhang,Cai-Shui Wang,Qian Zhou,Hai-Mu Ye
Biodegradable poly(1,4-butylene adipate) (PBA) has been highlighted of distinct polymorphism and receives extensive research by adding nucleating agents. Usually, only a single nucleating mechanism is proposed for each composite system, which should not be sufficient. In present work, 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol sorbitol (NX), a commercial sorbitol derivative, was incorporated into the PBA matrix to regulate the crystallization behavior. It is found that the non-isothermal crystallization temperature rises first and then declines, but the α-form crystal-forming ability becomes stronger with the increasing NX content, which is due to the limited solubility of NX in PBA. When NX is totally dissolved, the specific butterfly molecular shape of NX helps PBA chains form the gauche conformation, simultaneously promoting the crystallization rate and α crystal formation. However, once the NX content is ≥1%, crystallites of NX appear and play as physical cross-linking points for PBA chains; then, the mobility restriction becomes the major mechanism, which would slow down the crystallization rate but significantly enhance the formation of the α-form crystal-forming ability. PBA/NX composites possess a considerably lower degradation rate than neat PBA. Thus, this work demonstrates a novel additive of the dual mechanism to regulate the crystallization behavior and further the degradation rate of PBA.
研究领域:
材料科学
·
聚合物化学
·
生物可降解聚合物
✓ 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）