RSC Advances
·
2017
·Vol. 7
·期 36
·22485-22491
·
IF 3.108
Hailiang Zhao,Shanshan Tang,Qun Zhang,Lin Du
The weak intermolecular interaction between 2,2,2-trifluoroethanol (TFE) and 3-chloro-2-methyl-1-propene (CMP) has been investigated by gas phase FTIR spectroscopy and DFT calculations. CMP offers two hydrogen bond docking sites to the hydrogen bond donor: the chlorine atom (O–H⋯Cl) and the CC π electron system (O–H⋯π). DFT calculations suggest that MeOH approaches CMP in five different orientations. The structural, energetic, and spectroscopic parameters of the most stable structures in each orientation were studied, and their binding energies range from −25.5 to −19.5 kJ mol−1. The docking to the π system is at least 1 kJ mol−1 more favored than the docking to the chlorine atom. The equilibrium constant for complexation (2.3 × 10−2) was determined from the experimental and calculated intensity of the OH-stretching transition. The Gibbs free energy of formation was found to be 9.3 kJ mol−1. The nature of the non-covalent interaction was analyzed with the atoms in molecules (AIM) method.
研究领域:
物理化学
·
结构化学
·
分子光谱学
·
量子化学计算
·
分子间相互作用
✓ 已验证
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2016
·
IF 4.425
Yajing Wang,Yingnan Chi,Wenwen Zhang,Qiuhong Yang,Song Yang,Chong Su,Zhengguo Lin,Jingkai Gu,Changwen Hu
Four hemihydrates (HH-I, HH-II, HH-III, and HH-IV) and two monohydrates (MH-I, MH-II) of diosgenin, a steroid sapogenin, have been prepared. Hydrates HH-I, HH-III, HH-IV, MH-I, and MH-II have been thoroughly characterized by single-crystal X-ray diffraction, powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry, and differential scanning calorimetry. Although in these cases diosgenin has a similar conformation, hydrogen bonding interactions connect diosgenin and the lattice water molecule into different supermolecular structures. More importantly, three controlling factors, including initial concentration, water volume fraction, and solvent, have been investigated in the crystallization of diosgenin hydrates. The control experiments in ethanol display that as the initial concentration increases, HH-III, HH-I, and HH-II appear in order, and with the increase of water content, HH-I, HH-III, MH-I, and MH-II are obtained correspondingly. When acetone is used as solvent, HH-IV was synthesized. Moreover, we observed that stick-like crystals of HH-III gradually transform to plate-like ones of MH-I in solution at ambient conditions. This transformation is prevented by lowering temperature and is accelerated by adding water.
研究领域:
晶体工程
·
药物化学
·
固态化学
·
结构化学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2023
·Vol. 52
·期 21
·7143-7151
·
IF 4
Lu Liang,Xiaohui Li,Xiaoge Wang,Zhaoji Luo,Kun Lin,Qiang Li,Sihao Deng,Lunhua He,Xiaojun Kuang,Xianran Xing
Mixed electronic and oxide ionic conduction was enabled in digermanate-type La2−xCaxGe2O7−x/2 containing Ge3O10 chains and isolated GeO4 units by substitution of La3+ with Ca2+. The structure and solid solution limit of Ca doped La2Ge2O7 were studied by systematic experiments, including rotation electron diffraction (RED), X-ray diffraction (XRD) and neutron powder diffraction (NPD) experiments, etc. The preferred occupation of Ca2+ and oxygen vacancies was investigated by Rietveld analysis of the NPD data. The obtained conducting material La1.925Ca0.075Ge2O6.963 exhibits superior thermal stability and an order of magnitude improvement in conductivity compared to the parent La2Ge2O7 (∼9 × 10−5 S cm−1 at 1000 °C). BVEL calculations reveal that the oxygen vacancies were stabilized and transported within the framework of La2Ge2O7 by sharing oxygen and oxygen exchange between the adjacent Ge3O10 chains and GeO4 units, exhibiting a three-dimensional oxide ion transport nature.
研究领域:
无机化学
·
固态离子学
·
功能材料
·
结构化学
·
能源材料
·
晶体化学
✓ 已验证
DOI
高影响因子
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
·
2021
·Vol. 647
·期 6
·681-685
·
IF 1.492
Xieyang Wang,Zhen Dong,Rui Yang,Shengren Zhou,Zhiwen Ye
Two energetic salts of cyclo-N 5 − , O-methylisoure pentazolate ( 1 ) and guanidinoacetic acid pentazolate ( 2 ), were synthesized by metathesis reaction. All the energetic cyclo-N 5 − salts were characterized by single-crystal XRD, IR spectroscopy, 1 H and 13 C multinuclear NMR spectroscopy, thermal analysis (DSC) and elemental analysis. They exhibit good thermal stability with decomposition temperatures of more than 100 °C and they are in excellent agreement with those reported non-metallic salts. Salt 1 also exhibits strong π-π interactions. The standard enthalpies of formation and detonation performances of these salts were calculated using Gaussian 09 and EXPLO5 v6.01 programs. The detonation velocities of compound 1 and 2 are both about 7400 m s −1 and these two salts exhibit low mechanical sensitivity (IS>23 J, FS>220 N). Therefore, in this work, the synthesis of the new pentazolate salts enriches the cyclo-pentazolate salts system, which is conducive to the exploration of more heat-resistant and higher detonation velocities pentazolate salts.
研究领域:
无机化学
·
含能材料
·
热分析
·
结构化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2017
·
IF 1.753
Yan Shi,Xue-Jie Tan,Dian-Xiang Xing,Qi-Cheng Sui,Bin Liu,Wen-Quan Feng,Yun Liu
In this manuscript, we report the synthesis, NMR and single-crystal structures of three propylene linking dimers related with the hydrolytic degradation of one 5,6-dehydronorcantharimide dimer. Special attention was paid to the conformation of propylene linkers in order to understand their changes in the reaction. Statistical analysis of CSD database revealed that a-a, g-a and g-g conformations may have similar stability in most cases and various complicated unpredictable non-covalent interactions may play important role in the formation of final rotamers . In order to reproduce all stable conformations and the energy barriers separating them, full range two-dimensional fully relaxed potential-energy surfaces (PES) scans of six ‘propylene linker’ dimers were calculated starting from the most stable crystal structures. The PES were scanned along both bridge C C single bond torsional angles (denoted as θ 1 and θ 2 ), while all other internal coordinates were optimized at the DFT/B3LYP/3-21G* level in gas phase. Then all energy minima were re-optimized again at the DFT/B3LYP/6-311 + G(d,p) level both in gas and ethanol solutions in order to evaluate the really stable rotamers. At last, 1D or 2D relaxed PES scans were performed between local stable rotamers to get reliable energy barriers. This method represents a less time-consuming and more reliable approach to the determination of conformational stability of propanediyl bridging chains. The combination of experimental, statistical and theoretical results shows that the observed conformation is jointly determined by the energy levels of the minima, energy barriers separating them, non-covalent interactions and somewhat randomness.
研究领域:
有机化学
·
计算化学
·
结构化学
·
物理有机化学
✓ 已验证
DOI
高影响因子
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