HELVETICA CHIMICA ACTA
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2017
·Vol. 100
·期 12
·e1700162
·
IF 1.071
Jun Wang,Rui Gao,Na Zhang,Xiangkun Tan,Libo Wang,Lili Ma,Weiguang Shi
Three dendritic PNP ligands with ethylenediamine, 1,4-butanediamine, 1,6-diaminohexane as bridged groups are synthesized in good yields, respectively. Three dendritic PNP chromium complexes ( C1 – C3 ) are prepared with the ligands and chromium(III) chloride tetrahydrofuran complex (CrCl 3 (THF) 3 ) as materials. The dendritic PNP ligands and the synthetic chromium complexes are fully characterized by spectroscopic and analytical methods. All chromium complexes activated with methylaluminoxane (MAO) exhibited moderate activities on ethylene oligomerization (7.90 × 10 4 – 2.15 × 10 5 g (mol Cr h) −1 ] and had better selectivity for C 6 and C 8 oligomer, reaching up to 81%. The chromium complex ( C1 ) activated with diethylaluminium chloride (Et 2 AlCl) has higher catalytic activity than the chromium complex C1 activated with MAO, although the chromium complex ( C1 ) activated with Et 2 AlCl had lower selectivity for C 6 and C 8 oligomer. The effects of solvent and reaction parameters on ethylene oligomerization are also studied using the chromium complex C1 as pre - catalyst and MAO as co - catalyst. Under optimized conditions ([complex] = 2 μmol, Al/Cr = 500, 25 °C, 0.9 MPa ethylene, 30 min), the catalytic activity of complex C1 in toluene is 2.15 × 10 5 g (mol Cr h) −1 and the selectivity for C 6 and C 8 oligomer is 36.76%. In addition, the structure of complexes significantly affects both the catalytic activity and the selectivity on ethylene oligomerization.
研究领域:
化学
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材料科学
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DOI
高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2020
·Vol. 34
·期 11
·e5904
·
IF 3.14
Cuiqin Li,Dan Li,Fengfeng Wang,Yuxin Gao,Jin Huang,Feng Li
Series of hyperbranched PNP ligands ( L1 – L3 ) were prepared using three low-generation hyperbranched molecules with the same branching chains and functional groups but different alkyl chain length as backbones in a mixed solvent of acetonitrile and dichloromethane. The chromium complexes ( Cr1 – Cr3 ) were obtained by reacting with CrCl 3 (THF) 3 and the corresponding ligands ( L1 – L3 ). Both L1 – L3 and Cr1 – Cr3 were characterized by elemental analysis, Fourier transform infrared and electrospray ionization–mass spectrometry as well as 1 H nuclear magnetic resonance (NMR) and 31 P NMR measurements in the case of the ligands. When activated with different aluminum co-catalysts, all three chromium complexes were able to catalyze the ethylene oligomerization, but the products of the ethylene oligomerization were mainly dependent on ethylene pressure, co-catalyst and ligand backbone. Upon activation with methylaluminoxane, the catalytic activity and the selectivity of C8 olefin increased with increasing of ethylene pressure for Cr1 , the catalytic activity was 13.83 × 10 5 g·(mol Cr·h) −1 and the main product was C8 olefin (50.68%) at the ethylene pressure of 4.0 MPa. When activated with diethylaluminium chloride, ethylaluminium dichloride and ethylaluminum sesquichloride, Cr1 showed the lower catalytic activity and the higher selectivity of C4 olefin in toluene. An increase in the length of alkyl chain in the hyperbranched PNP ligand backbone caused a decrease in the catalytic activity and an increase in the selectivity of C8 + olefin. The PNP chromium complexes exhibited higher selectivity for higher carbon number olefins compared with the dendritic PNP chromium complex ( Cr5 ).
研究领域:
化学
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材料科学
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DOI
高影响因子
JOURNAL OF COORDINATION CHEMISTRY
·
2019
·
IF 1.685
Jun Wang,Jinyi Liu,Tianyu Lan,Liduo Chen,Libo Wang
Two new hyperbranched bispyridylamine ligands and multinuclear chromium complexes were synthesized with 1.0 G hyperbranched macromolecules, 2-chloropyridine, 2-chloro-4-methylpyridine and CrCl3(THF)3 as raw materials. The structures of hyperbranched ligands and chromium complexes were characterized by UV, FT-IR, 1H NMR, ESI-MS, and elemental analysis. These hyperbranched chromium complexes were evaluated as catalyst precursors by using MAO as activator in the oligomerization of ethylene. Effects of reaction temperature, reaction pressure, Al/Cr molar ratio, concentration of catalyst, solvent, and the structure of catalysts on the catalytic activity and product selectivity were investigated. The oligomerization results showed that with increase of reaction temperature, reaction pressure, and Al/Cr molar ratio, the catalytic activity increased and then decreased; the catalytic activity continuously decreased as the amount of catalyst increased. The products were mainly based on C6 and C8. Under optimized conditions, the catalytic system of hyperbranched NNN/Cr(III)/MAO led to activity of 1.26 × 105 g/(mol·Cr·h) and 63.34% selectivity for C6 and C8.
研究领域:
化学
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材料科学
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DOI
高影响因子
JOURNAL OF COORDINATION CHEMISTRY
·
2017
·
IF 1.795
Jun Wang,Na Zhang,Weiguang Shi,Yiteng Shang,Cuiqin Li
Two hyperbranched bisphosphinoamine (PNP) ligands and chromium complexes were synthesized in good yield with 1.0 generation (1.0 G) hyperbranched macromolecules, chlorodiphenylphosphine (Ph2PCl) and CrCl3(THF)3 as raw materials. The hyperbranched PNP ligands and chromium complexes were characterized by FT-IR, 1H NMR, 31P NMR, UV and ESI-MS. Comparing with the chromium complexes, the hyperbranched PNP ligands, in combination with Cr(III), and activation by methylaluminoxane (MAO) in situ generated species with better catalytic performance for ethylene oligomerization. The effect of solvent, chromium source, ligand/Cr molar ratio, reaction temperature, Al/Cr molar ratio and reaction pressure on the catalytic activity and product selectivity were studied. The results showed that with increase of ligand/Cr molar ratio, reaction temperature and Al/Cr molar ratio, the catalytic activity increased at first and then decreased. However, the catalytic activity continuously increased with increase of reaction pressure. Under the optimized conditions, the catalytic system of hyperbranched PNP/Cr(III)/MAO led to catalytic activity of 2.68 × 105 g/(mol Cr·h) and 37.71% selectivity for C6 and C8.
研究领域:
有机化学
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催化化学
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DOI
高影响因子
Journal of Environmental Chemical Engineering
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2022
·
IF 7.968
Tiantian Feng,Qing Liu,Can Yang,Guiju Li,Jin Liu
Considering the stability and hazard of chromium complexes, their removal and recovery from industrial wastewater is a worthy goal. Membrane capacitive deionization (MCDI) can effectively reduce co-ion adsorption compared with CDI technology and has been demonstrated to be a promising deionization technology. In this study, functionalized activated carbon (AC@SiO 2 -NH 2 ) was applied as a MCDI eletrode. The AC@SiO 2 -NH 2 adsorbs chromium complexes (Cr(Ⅲ)-EDTA) through electrostatic gravitation of protonated amino groups (-NH 3 + ). With applied voltage of 1.2 V, solution flow rate of 20 mL min −1 and initial concentration of 300 mg L −1 , the electrosorption capacity of the AC@SiO 2 -NH 2 electrode for Cr(Ⅲ)-EDTA was 17.70 mg g −1 . The Ragone curves verified that the electrosorption rate (SER) of the AC@SiO 2 -NH 2 electrode was positively correlated with voltage and initial concentration. Moreover, the effects of competing ions (K + , Na + , and Mg 2+ ) in a series of single electrolyte solution by the AC@SiO 2 -NH 2 electrode were investigated. It was also verified that the optimum pH was 3 for electrostatic attraction. The energy consumption of the MCDI process is calculated as 0.251 kWh m 3 and 0.039 kWh g −1 Cr at 1.2 V. We envisage that the use of AC@SiO 2 -NH 2 electrodes will pave the way for efficient operation of MCDI as well as the preferential recovery of Cr(Ⅲ)-EDTA.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2024
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IF 12.2
Ningyi Chen,Shuang Wu,Ying Xu,Sijie Lv,Xianhua Wang,Qingrui Zhang,Bingjun Pan
High-resolution identification of chromium (Cr) species, especially various organic-Cr complexes, in a convenient and economically-feasible manner is the prerequisite for achieving the advanced treatment of chromium wastewater. To this end, a colorimetric nano-Au sensor array was developed by taking advantage of the UV-spectra shift of gold nanoparticles (Au NPs) upon interaction with Cr species; specifically, four molecular modifiers [i.e., iminodiacetic acid (IDA), tripolyphosphate (TPP), cetyltrimethylammonium bromide (CTAB), and 1,5-diphenylcarbazide (DPC)] were intentionally employed for assembling nano-Au array receptors, which showed respective responses toward different Cr species through the formation of coordination, hydrophobic interaction, electrostatic attraction, and redox reaction , respectively; the “fingerprint” differences of the unique optical properties were then integrated for semi-quantitatively recognizing Cr species by pattern recognition techniques. Eleven ubiquitous Cr species [i.e., Cr(III), Cr(VI), and various Cr(III)-organic complexes] served as the model samples, which could be sensitively identified, no matter in individual or mixture mode, by the developed nano-Au sensor array on the basis of the colorimetric responses resulted from diverse nano-Au-aggregation behaviors, with excellent anti-interference ability in the simulated or actual water scenario. Attractively, the nano-Au sensor array can achieve very sensitive detection limit of the quantitative analyses of Cr species in a prompt in-situ manner, which usually requires a two-step process of separation and detection for the conventional analytical methods. Such a convenient strategy of Cr species discrimination conduces to rationally designing specific protocols for the advanced treatment of chromium wastewater.
研究领域:
环境科学
·
分析化学
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产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Yi Liu,Shuangjiang Li,Xiaojian Yu,Ying Chen,Xiaoning Tang,Tianding Hu,Lan Shi,Manoj Pudukudy,Shaoyun Shan,Yunfei Zhi
For the simultaneous attainment of the utilization of renewable biomass resources and the mitigation of greenhouse effects, it is very promising to develop a green, recyclable, and highly efficient heterogeneous catalyst for the synthesis of cyclic carbonates by CO 2 cycloaddition reaction with epoxides. Herein, novel cellulose nanofibers (CNF) supported (Salen)Cr(Ⅲ) complex was effectively synthesized for the aforementioned reaction. The cellulose nanofibers (CNF) were firstly modified with (3-aminopropyl) triethoxysilane (APTES), and then its Schiff base with salicylaldehyde was synthesized, which further subjected to coordination treatment with chromium chloride to form a novel heterogeneous catalyst, labelled as CNF-(Salen)Cr(Ⅲ). The catalytic performance of the catalysts shown that CNF-(Salen)Cr(Ⅲ) and co-catalyst TBAB can synergistically catalyze the cycloaddition of CO 2 with epichlorohydrin (ECH) at mild reaction conditions, and the yield of chloropropene carbonate (CPC) reached up to 97.8% with high selectivity. The CNF-(Salen)Cr(Ⅲ) complex maintained high catalytic activity after six cycles of repeated runs and has acceptable catalytic effect on other series of epoxies. Based on density functional theory (DFT) calculations, a reaction mechanism including adsorption activation of epoxides, epoxides ring opening, CO 2 insertion, and the formation of cyclic carbonate, was proposed for the CNF-(Salen)Cr(Ⅲ) complex catalyzed cycloaddition of CO 2 with epoxides.
研究领域:
绿色化学
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催化化学
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材料科学
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DOI
高影响因子
Journal of Advanced Research
·
2022
·
IF 12.822
Xiaodong Ge,Xiaoyu He,Junwei Liu,Feng Zeng,Ligen Chen,Wei Xu,Rong Shao,Ying Huang,Mohamed A. Farag,Esra Capanoglu,Hesham R. El-Seedi,Chao Zhao,Bin Liu
Introduction Luteolin is a plant-derived flavonoid that exhibits a broad range of pharmacological activities. Studies on luteolin have mainly focused on its use for hyperlipidaemia prevention, whereas the capacity of the flavonoid to hinder hyperglycaemia development remains underexplored. Objectives To probe the anti-hyperglycemic mechanism of 6,8-guanidyl luteolin quinone-chromium coordination (GLQ.Cr), and to assess its regulatory effect on intestinal microbiota in type 2 diabetes mellitus (T2DM) mice. Methods High-sucrose/high-fat diet-induced and intraperitoneal injection of streptozotocin was used to develop a T2DM model. Glycometabolism related indicators, histopathology, and gut microbiota composition in caecum samples were evaluated, and RNA sequencing (RNA-seq) of liver samples was conducted. Faecal microbiota transplantation (FMT) was further used to verify the anti-hyperglycemic activity of intestinal microbiota. Results The administration of GLQ.Cr alleviated hyperglycaemia symptoms by improving liver and pancreatic functions and modulating gut microbe communities ( Lactobacillus, Alistipes , Parabacteroides , Lachnoclostridium , and Desulfovibrio ). RNA-seq analysis showed that GLQ.Cr mainly affected the peroxisome proliferative activated receptor (PPAR) signalling pathway in order to regulate abnormal glucose metabolism. FMT significantly modulated the abundance of Lactobacillus , Alloprevotella , Alistipes , Bacteroides, Ruminiclostridium, Brevundimonas and Pseudomonas in the caecum to balance blood glucose levels and counteract T2DM mice inflammation. Conclusion GLQ.Cr improved the abnormal glucose metabolism in T2DM mice by regulating the PPAR signalling pathway and modulating intestinal microbial composition. FMT can improve the intestinal microecology of the recipient and in turn ameliorate the symptoms of T2DM-induced hyperglycaemia.
研究领域:
药理学
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糖尿病
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微生物学
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分子生物学
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生物化学
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DOI
PubMed
高影响因子
Food & Function
·
2022
·Vol. 13
·期 6
·3572-3589
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IF 6.317
Xiaodong Ge,Xiaoyu He,Zhenshan Lin,Yuxian Zhu,Xiaoqin Jiang,Liyuan Zhao,Feng Zeng,Ligen Chen,Wei Xu,Tingting Liu,Zhigang Chen,Chao Zhao,Ying Huang,Bin Liu
Flavonoid compounds such as luteolin exhibit hypolipidemic effects, and there are few reports on the hypoglycemic activity of luteolin derivatives. In this research, 6,8-(1,3-diaminoguanidine) luteolin (DAGL) and its Cr complex (DAGL·Cr) were obtained as a result of structural modifications to luteolin, and the hypoglycemic activities and the composition of intestinal microbiota in T2DM mice were investigated. This study found that DAGL and DAGL·Cr could significantly restore body weight, FBG, OGTT, AUC, and GSP in T2DM mice. Moreover, the pancreatic islet function index and the biochemical indicators of serum and the liver were also significantly improved. The histopathological results also showed that DAGL and DAGL·Cr had a stronger repair ability in the liver and the pancreas. It was also revealed that the potential hypoglycemic mechanism of DAGL and DAGL·Cr was involved in the simultaneous regulation of PI3K/AKT-1/GSK-3β/GLUT-4 and PI3K/AKT-1/mTOR/S6K1/IRS-1. Furthermore, DAGL and DAGL·Cr could also regulate the structure of the intestinal microbiota and increase the content of SCFA to relieve the symptoms of hyperglycemia in T2DM mice. This included a significant reduction in the ratio of Firmicutes and Bacteroidetes (F/B), and at the genus level, an increase in the relative abundance of Alistipe and Ruminiclostridium, and improvement in the content of SCFA in the feces of T2DM mice. In conclusion, in this study, DAGL and DAGL·Cr were found to improve hyperglycemia in T2DM mice by improving the pancreatic islet function index, regulating the biochemical indicators of serum and the liver, repairing damaged tissues, and regulating the PI3K/AKT-1 signaling pathway as well as reducing F/B, increasing the relative abundance of intestinal beneficial microbiota, and the content of SCFA in the feces. The hypoglycemic effect of DAGL·Cr on the body weight, serum IL-10, serum IL-6, and pancreatic islet function index was significantly better than that of DAGL.
研究领域:
药理学
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糖尿病研究
·
微生物学
·
分子生物学
✓ 已验证
DOI
PubMed
高影响因子
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