INORGANICA CHIMICA ACTA
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2019
·
IF 2.433
Dang Yang,Qiao Gan,Huafeng Chen,Weilun Ying,Junyi Zhao,Xiaoyu Jia,Dirong Gong
Four cobalt complexes supported by phosphine oxide (P=O) donors (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphine oxide) cobalt dichloride (Co1) , (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphine oxide) cobalt bromide (Co2) , N, N'-(pyridine-2,6-diyl)bis(P,P-di- tert -butylphosphinic amide) cobalt dichloride (Co3) and N, N'-(pyridine-2,6-diyl)bis(P,P-di- tert -butylphosphinic amide) cobalt dichloride (Co4) were prepared and characterized. Their catalyses performances in polymerization of isoprene, butadiene, myrcene as well as MMA and styrene were examined. In combination with AlEt 2 Cl, Co1 and Co2 are able to convert isoprene to polyisoprene, whereas the activities of Co3 and Co4 are much low. The resultant polyisoprene are mixture of cis -1,4 and 3,4 isomers, whose ratio are not significantly affected by the type of catalysts and polymerization conditions. Isoprene was found to be more active than myrcene, and butadiene in the case of Co1 /AlEt 2 Cl, suggestive of compromised sterical and electronic effect from the alkyl group at 2-positon of monomers. The Co1 /AlEt 2 Cl system is also moderately active in polymerizations of methyl methacrylate and styrene. Therefore, the current catalysts provided dual polymerization reactivities towards conjugated dienes and olefins that are rare in transition metals catalyzed coordinative polymerization.
研究领域:
高分子化学
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催化化学
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产品关联
DOI
高影响因子
MACROMOLECULAR RAPID COMMUNICATIONS
·
2024
·Vol. 45
·期 22
·2400486
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IF 4.2
Liying Shen,Jingjing Zhai,Yanchen Huo,Xiuling Wang,Xiaochao Shi
A series of binuclear rare-earth metal complexes based on the ligands containing bis(phosphinophenyl)amido-PNP unit are successfully synthesized. All the ligands and the corresponding binuclear complexes are fully characterized by NMR spectra ( 1 H, 13 C, and 31 P). In conjunction with [Ph 3 C][B(C 6 F 5 ) 4 ], all the binuclear complexes exhibited high catalytic activity and high cis -1,4-selectivity (>99%) toward the polymerization of 1,3-conjugated dienes (isoprene, β-myrcene and β-farnesene) with excellent livingness at room temperature or even 80 °C.
研究领域:
有机化学
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高分子化学
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催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INORGANIC CHEMISTRY
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2021
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IF 5.165
Fen You,Jingjing Zhai,Yat-Ming So,Xiaochao Shi
A convenient synthetic route has been developed for preparing the novel rigid 4,5-(PR2)2–2,7,9,9-tetramethylacridane-based pincer ligands (acri-RPNP; R = iPr and Ph), and the first rare-earth (Ln = Y, Lu) alkyl complexes bearing the acri-RPNP ligands were synthesized by a salt metathesis reaction (for the isopropyl-substituent acri-iPrPNP complexes, 1-Ln) or direct alkylation (for the phenyl-substituent acri-PhPNP complexes, 2-Ln). For both 1-Ln and 2-Ln, the NMR spectroscopy and X-ray diffraction study confirmed the successful coordination of the acri-RPNP ligand to the central metal ion in a tridentate manner via the two phosphine and the nitrogen donors. In contrast to 1-Ln that are solvent-free complexes, the metal centers in 2-Ln are each coordinated with one tetrahydrofuran molecule. Upon activation by [Ph3C][B(C6F5)4], 1-Y and 2-Lu could catalyze the living polymerization of isoprene and β-myrcene with high catalytic activity and high cis-1,4-selectivity (up to 92.3% for isoprene and 98.5% for β-myrcene). Moreover, the 1-Y/[Ph3C][B(C6F5)4] catalytic system also could promote the polymerization of butadiene and its copolymerization with isoprene to produce copolymers with high cis-1,4-selectivity and narrow polydispersity.
研究领域:
化学
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材料科学
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催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ORGANIC CHEMISTRY
·
2023
·
IF 3.6
Zi-Heng Zhang,Li-Jun Han,Shuang-Shuang Ma,Yi-Ran Du,Zheng-Kun Yu,Jin-Qing Lin,Bao-Hua Xu
The Pd(cod)Cl2-catalyzed alkoxycarbonylation of conjugated dienes to β,γ-unsaturated esters was approached by both intramolecular phosphinesulfonate L1 and intermolecular PPh3/PTSA in this study. However, the poor solubility of the Pd/L1 complex and the labile monodentate Pd/PPh3 structure restricts the system efficiency, especially for the scale-up application. By contrast, the stable and well-soluble bidentate Xantphos system allows for the quantitative formation of 3-pentenoate (96%) on a gram scale within 6 h in weakly alkaline N-methylpyrrolidone (NMP), which also functions as a basic site to promote the rate-limiting alcoholysis step while reducing the dosage of ligand to a theoretical value.
研究领域:
有机化学
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催化
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合成化学
✓ 已验证
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
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2022
·Vol. 57
·期 3
·1718-1728
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IF 3.612
Ying Luo,Ao Li,Miao Shen,Man-Man Yu,Zi-Xuan Wu,Xiao-Yang Liu,Fa-Wen Yin,Da-Yong Zhou
Summary The process of lipid oxidation in fresh and fried oysters during in vitro digestion and the relationship between the antioxidant ability of phenolic esters with different chain lengths were investigated through co-digestion of fresh and fried oysters with gallic acid (GA) and its alkyl esters. Lipid oxidation in fresh and fried oysters during simulated digestion in vitro was observed according to increased conjugated diene value, conjugated triene value, thiobarbituric acid reactive substances and fluorescence intensity of aldehydes. Lipid oxidation in oysters was inhibited by GA and its alkyl esters during in vitro digestion effectively. As the alkyl chain length increased, the antioxidant effect first increased and then decreased, and butyl gallate achieved the highest effect among the GA and its alkyl esters we studied, which suggests that the antioxidant efficiency of GA and its alkyl esters in the digestive system may follow the ‘cut-off’ effect.
研究领域:
食品科学
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营养学
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生物化学
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胃肠生理学
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产品关联
DOI
高影响因子
Food & Function
·
2024
·
IF 5.1
Ruiying Wang,Xin Sun,Guimei Dong,Chao Guo,Fawen Yin,Huilin Liu,Liang Song,Dayong Zhou
Lipid oxidation profoundly impacts its digestibility, a topic that has been predominantly investigated in triglyceride (TAG)-based dietary lipids. However, there is a dearth of similar research on lipids with diverse classes, such as Antarctic krill oil (AKO), which encompasses a spectrum of lipids including glycerides and phospholipids. This study aimed to elucidate the influence of lipid oxidation on the digestibility of AKO through a simulated gastrointestinal digestion (SGID) model. Post-SGID, AKO exhibited oxidative changes, evidenced by an escalation in peroxide value, conjugated diene value, thiobarbituric acid reactive substances and Schiff base formation. Concurrently, the digestibility of oxidized AKO was found to be inferior to that of fresh AKO, as indicated by a diminished hydrolysis degree of TAGs and phosphatidylcholine (PC), along with a reduced release of free fatty acids. Furthermore, co-digestion with tea polyphenol palmitate was observed to mitigate the oxidation of AKO and the digestion of PC during the SGID, while exerting no significant impact on TAG digestion. Notably, the emulsification capacity of oxidized AKO in a simulated intestinal fluid (without pancreatin and phospholipase A2) was also found to be inferior to that of its fresh counterpart. These findings suggest that lipid oxidation may adversely affect the emulsification capacity of AKO under simulated intestinal conditions, thereby leading to a decrement in digestibility.
研究领域:
食品科学
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营养学
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生物化学
✓ 已验证
DOI
PubMed
高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
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2020
·
IF 4.006
Yingjie Bao,Xiaopu Ren,Yuxia Zhu,Yawei Zhang,Zengqi Peng,Guanghong Zhou
The effects of 7 spice extracts on lipid radical formation were first collectively studied in situ in roasted beef by electron spin resonance (ESR). And the correlations among the ESR and conventional indexes including 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging capacity, reducing power, oxygen radical absorption capacity (ORAC), conjugated diene value (CDV) and thiobarbituric acid-reactive substances (TBARS) were also analysed. Clove was observed the highest scavenging lipid radical and DPPH radical capacity, and rosemary showed the highest peroxyl radical scavenging capacity, while tert-butylhydroquinone (TBHQ) significantly increased lipid radicals in roasted beef ( p < 0.05). ESR showed significant correlations with the DPPH and CDV assays ( p < 0.05) but no correlation with the ORAC and TBARS assays ( p > 0.05), indicating that with the addition of spice extracts, the lipid radical formation in roasted beef could be predicted by the DPPH assay but not be appropriate to evaluate the oxidation stability in roasted beef.
研究领域:
食品科学
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化学
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营养学
✓ 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）