PHOTOCHEMISTRY AND PHOTOBIOLOGY
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2022
·
IF 3.521
Ziwei Chen,Xueli Wang,Menghui Jia,Xiaoxiao He,Haifeng Pan,Jinquan Chen
5-Azacytosine (5-AC) is one of the best interesting noncanonical nucleobases due to its functionalization and structural imitation of natural bases. 5-AC can be used as the scaffold of two important chemotherapeutic medicines, 5-azacytidine and 2′-deoxy-5-azacytidine. Furthermore, increased sensitivity to UV leads to the photochemical effects of 5-AC also attracted attention. Yet, no study has been reported to explore the effect of glycosyl groups on the photophysical and photochemical properties of 5-AC, which can help to reveal the photostability of related actual clinic drugs. In this study, the excited-state dynamics of 5-azacytidine and 2′-deoxy-5-azacytidine are studied by femtosecond transient absorption and quantum-chemical calculations while revisiting that of 5-AC with a wider probe spectral range. It is shown that glycosyl substitution on the N1 position leads to ultrafast excited-state relaxation within several picoseconds in both nucleosides, which is distinct compared with the 17 ps lifetime seen in 5-AC. It is proposed that these changes are due to altering the energy level of the dark nπ* state. Moreover, our results suggest that it should be cautioned to simply replace sugar groups with methyl groups when doing a theoretical calculation study on nucleobases and their derivatives.
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高影响因子
MOLECULES
·
2022
·Vol. 27
·期 15
·5020
·
IF 4.927
Yu Zhang,Ying-Jie Zhu,Han-Ping Yu
Ultralong hydroxyapatite (HAP) nanowires are promising for various biomedical applications owing to their chemical similarity to the inorganic constituent of bone, high biocompatibility, good flexibility, excellent mechanical properties, etc. However, it is still challenging to control the formation of ultralong HAP nanowires because of the presence of free PO43−ions in the reaction system containing the inorganic phosphate source. In addition, it takes a long period of time (usually tens of hours) for the synthetic process of ultralong HAP nanowires. Herein, for the first time, we have developed an eco-friendly calcium oleate precursor microwave hydrothermal method using biocompatible adenosine 5′-triphosphate (ATP) as a bio-phosphorus source and water as the only solvent for the rapid synthesis of ultralong HAP nanowires. The controllable hydrolysis of ATP can avoid the premature formation of calcium phosphate nuclei and uncontrollable crystal growth. Microwave heating can significantly shorten the synthetic time from tens of hours required by the traditional heating to 1 h, thus achieving high efficiency, energy saving and low cost. The as-prepared ultralong HAP nanowires with high flexibility have lengths of several hundred micrometers and diameters of 10~20 nm, and they usually self-assemble into nanowire bundles along their longitudinal direction. The as-prepared ultralong HAP nanowire/chitosan porous scaffold has excellent bioactivity, good biodegradation and cytocompatibility owing to the bioactive adenosine adsorbed on the surface of ultralong HAP nanowires. It is expected that ultralong HAP nanowires will be promising for various applications in the biomedical fields, such as bone defect repair, skin wound healing, and as a drug nanocarrier.Keywords:nanowire;hydroxyapatite;microwave;hydrothermal;adenosine triphosphate
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ENVIRONMENTAL POLLUTION
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2022
·
IF 9.988
Xiao-Yan Cao,Yuan-Zhe Ni,Jing Li,Ling Li,Yi-Lin Zhao,Gui-Peng Yang
In this paper, the kinetics and thermodynamics of Adenosine 5′-monophosphate (AMP) sorption on the sediments obtained from the Yangtze River Estuary and adjacent areas were studied, in combination with the effects of the sediments' properties and media conditions. The kinetics curves could be described by a two-compartment first-order equation, and the equilibrium isotherms fitted well with the modified Langmuir and Freundlich models. The analysis of organic phosphorus (OP) fractions changes after sorption indicated that the contents of exchangeable or loosely sorbed P O increased most significantly. Higher organic matter (OM) of the sediments were favorable for the sorption ability. It was also found that the content of OP and OM in the sediments showed an obvious positive correlation, indicating that organic matter rather than Fe/Al oxides played an important role in the migration of OP in the Yangtze River estuary and its adjacent area. Temperature, salinity and pH of the media influenced the sorption of AMP significantly. Increase of temperature was of benefit to the sorption of AMP, which was a spontaneous and exothermic process according to the calculations of the thermodynamic parameters. The sorption capacity was higher at a moderate salinity in the range of our study. With the pH changing from 3 to 10, the sorption capacity exhibited as a “U-trend” curve.
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Microbial Cell Factories
·
2022
·Vol. 21
·期 1
·1-9
·
IF 6.352
Wang Yingying,Chen Xueman,Chen Qiaoyu,Zhou Ning,Wang Xin,Zhang Alei,Chen Kequan,Ouyang Pingkai
Background l-Tryptophan (l-Trp) derivatives such as 5-hydroxytryptophan (5-HTP) and 5-hydroxytryptamine (5-HT), N-Acetyl-5-hydroxytryptamine and melatonin are important molecules with pharmaceutical interest. Among, 5-HT is an inhibitory neurotransmitter with proven benefits for treating the symptoms of depression. At present, 5-HT depends on plant extraction and chemical synthesis, which limits its mass production and causes environmental problems. Therefore, it is necessary to develop an efficient, green and sustainable biosynthesis method to produce 5-HT.Results Here we propose a one-pot production of 5-HT from l-Trp via two enzyme cascades for the first time. First, a chassis cell that can convert l-Trp into 5-HTP was constructed by heterologous expression of tryptophan hydroxylase from Schistosoma mansoni (SmTPH) and an artificial endogenous tetrahydrobiopterin (BH4) module. Then, dopa decarboxylase from Harminia axyridis (HaDDC), which can specifically catalyse 5-HTP to 5-HT, was used for 5-HT production. The cell factory, E. coli BL21(DE3)△tnaA/BH4/HaDDC-SmTPH, which contains SmTPH and HaDDC, was constructed for 5-HT synthesis. The highest concentration of 5-HT reached 414.5 ± 1.6 mg/L (with conversion rate of 25.9 mol%) at the optimal conditions (substrate concentration,2 g/L; induced temperature, 25℃; IPTG concentration, 0.5 mM; catalysis temperature, 30℃; catalysis time, 72 h).Conclusion sThis protocol provided an efficient one-pot method for converting. l-Trp into 5-HT production, which opens up possibilities for the practical biosynthesis of natural 5-HT at an industrial scale.
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Frontiers in Chemistry
·
2022
·
IF 5.545
Xia Jing,Gao De,Han Feng,Lv Ruifu,Waterhouse Geoffrey I. N.,Li Yan
The catalytic hydrogenolysis of 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF) is a promising route towards sustainable liquid fuels with a high energy density. Herein, a novel CuCoNiAl-containing mixed metal oxide catalyst (CuCoNiAl-MMO) was prepared by calcination a layered double hydroxide (LDH) precursor in N2 at 500 °C, then applied for the catalytic hydrogenolysis of HMF to DMF. The effects of reaction time, reaction temperature and hydrogen pressure on DMF selectivity were investigated. Under relatively mild reaction conditions (180°C, 1.0 MPa H2, 6.0 h), CuCoNiAl-MMO showed both a high initial activity and selectivity for hydrogenolysis of HMF to DMF, with HMF conversion rate of 99.8% and DMF selectivity of 95.3%. Catalysts characterization studies using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) revealed the presence of various metal oxides and metallic copper on the surface of the CuCoNiAl-MMO catalyst, with the presence of mixed metal-oxide-supported metallic Cu nanoparticles being responsible good hydrogenolysis activity of the catalyst for selective DMF synthesis.
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JOURNAL OF RARE EARTHS
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2022
·
IF 4.632
Feng Lin,Yudan Zhong,Yulong Ma,Yonggang Sun,Xiuqin Men,Yingbo Zhu
Hydrodeoxygenation (HDO) of renewable lignin-derived biomass in aqueous-phase to produce high value-added products is of great significance. However, developing new catalysts with high activity and excellent stability in an aqueous phase faces considerable challenges. Rare earth doping can effectively regulate the water exchange rate constant (WERC) value of the catalyst and play an important role in promoting the hydrolysis of ether bonds. Therefore, in this paper the bimetallic supported catalyst Ni–La 2 O 3 /H-ZSM-5 doped with rare earth metal La 2 O 3 was prepared, and used to catalyze the conversion of the lignin model compound guaiacol to cyclohexanol in the aqueous phase. The conversion of guaiacol catalyzed by 10Ni–3La 2 O 3 /H-ZSM-5 reaches 100%, and the selectivity of the product cyclohexanol is 85%. A series of characterizations illustrate that the doping of La 2 O 3 causes the electron transfer between La 2 O 3 –Ni and changes the distribution of Ni, and a strong metal carrier interaction occurs between the bimetallic Ni–La 2 O 3 and H-ZSM-5. This can effectively promote the hydrolysis of the C–O ether bond in guaiacol and significantly improve the activity of the catalyst. The possible catalytic reaction mechanism of Ni–La 2 O 3 /H-ZSM-5 catalytic conversion of guaiacol was proposed.
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RSC Advances
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2022
·Vol. 12
·期 23
·14957-14963
·
IF 4.036
Hongtao Zhang,Xiao Liu,Miaomiao Han,Rui Zhang
5-Hydroxymethylfurfural (HMF) is a valuable platform chemical derived from biomass and lots of research focuses on the synthesis of HMF from fructose and glucose. Herein, conversion of bio-carbohydrates to 5-hydroxymethylfurfural (HMF) was studied in the three-component deep eutectic solvent (DES) system, which was composed of choline chloride (ChCl), boric acid and substrates such as fructose, glucose and sucrose. Bio-carbohydrates handled under typical reaction conditions gave satisfactory conversion (44% for fructose and 31% for glucose) and yield of HMF (35% for fructose and 21% for glucose) in 1 h. Moreover, owing to the benefits of DES, the initial substrate content could be higher and the reaction temperature could be reduced, thus side reactions were effectively avoided and the selectivity of HMF was better (ranging from 79% to 100% for fructose and from 65% to 100% for glucose). We believe this method could provide a promising alternative for conversion of bio-carbohydrates to HMF and a better utilization of biomass.
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Reaction Chemistry & Engineering
·
2022
·Vol. 7
·期 5
·1191-1198
·
IF 5.2
Linhao Yu,Saravanan Kasipandi,Hong Chen,Yingying Li,Xueli Ma,Zhe Wen,Yongdan Li
Cobalt nanoparticles embedded in graphitic nitrogen-rich carbon nanotubes (Co/GCN) were prepared with a facile method and employed as an efficient catalyst for oxidative esterification of 5-hydroxymethylfurfural (HMF). The introduction of N species to carbon benefits the synergistic effects between the Co nanoparticles and nitrogen-doped carbon nanotube substrate, which modify the surface chemical state of the Co/GCN catalyst and create abundant active sites to improve the HMF conversion. The Co/GCN catalyst carbonized at 800 °C exhibited the best catalytic performance with a 95.8% yield of furan-2,5-dimethylcarboxylate (FDMC) at 98.6% HMF conversion under mild reaction conditions. The effect of acid–base properties of the catalyst on the HMF conversion was investigated and the reaction mechanism of the HMF oxidative esterification was proposed.
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MATERIALS RESEARCH BULLETIN
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2022
·
IF 5.6
Yi Zhou,Jiaxin Li,Jin Zhang,Yongbo Chen,Tiantian Yao,Anna Chen,Minghui Xiang,Zhiyue Chen,Zhibin Wu
Dye sensitization is a pivotal method for the improvement of light utilization and electron transfer. Herein, a rhodamine B (RhB)-sensitized type Ⅱ DUT-5/BiVO 4 heterojunction was successfully synthesized. The results showed that the RhB sensitization process of DUT-5/BiVO 4 heterojunction merely affected the DUT-5 instead of BiVO 4 . SEM results showed that the regular DUT-5 nanoparticles were homogeneously dispersed on the surface of leaf-shaped BiVO 4 nanosheets. The as-fabricated samples were employed to degrade RhB and tetracycline (TC) under 300 W Xe lamp (λ ≧ 420 nm) irradiation. The RhB sensitized heterojunction showed considerably strengthened photocatalytic performance. The photodegradation efficiency of RhB sensitized BD-15% can achieve 82% for RhB after 60 min visible-light irradiation, and 71% for TC after 30 min visible-light irradiation. The dye-sensitized composites exhibit excellent photocatalytic activity ascribed to its boosted photoinduced electron transport, broadened visible-light response range and larger specific surface area. Moreover, a possible mechanism for pollutants photodegradation over RhB sensitized DUT-5/BiVO 4 was proposed.
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ChemSusChem
·
2022
·Vol. 15
·期 7
·e202200184
·
IF 9.14
Siyong Ou,Min Zhou,Wen Chen,Yuyao Zhang,Yueli Liu
Graphical Photocatalytic CO 2 reduction : A COF-5/CoAl-layered double hydroxide (LDH) heterojunction photocatalyst is developed for the CO 2 reduction reaction. CoAl-LDH incorporation enhances the visible-light response-ability of the photocatalyst and improves the separation efficiency of photogenerated electron–hole pairs through the role of a type-II heterojunction. Photocatalytic conversion of CO 2 into value-added chemical fuels is an attractive route to mitigate global warming and the energy crisis. Reasonable design of optical properties and electronic behavior of the photocatalyst are essential to improve their catalytic activity. Herein, the 1D/2D heterojunction by direct in-situ synthesis of the covalent organic framework (COF)-5 colloid on the surface of CoAl layered double hydroxide (LDH) was used as the prospective photocatalyst for CO 2 reduction. COF-5/CoAl-LDH nanocomposite achieved 265.4 μmol g −1 of CO with 94.6 % selectivity over CH 4 evolution in 5 h under visible light irradiation, which was 4.8 and 2.3 times higher than those of COF-5 colloid and CoAl-LDH, respectively. The enhanced catalytic activity was derived from the increased visible-light activity and the construction of type II-2 heterojunction, which greatly optimized visible light harvesting and accelerated the efficient separation of the photoinduced holes and electrons. This work paves the way for rational design of heterojunction catalysts in photocatalytic CO 2 reduction.
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高影响因子
FUEL
·
2022
·
IF 8.035
Yanbin Sun,Jianfeng Zheng,Jiajia Xu,Kaixuan Yang,Zhiguo Zhu,Ting Su,Hui Ge,Wanzhong Ren,Hongying Lü
Aerobic oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) is an environmentally sustainable, economically feasible, but substantially challenging conversion owing to the high energy barrier of O 2 activation. Herein, we report a catalyst with Mo 5+ connected to the oxygen vacancies (Mo 5+ -□) in Anderson-type polyoxometalate (POM) [(C 18 H 37 ) 2 N(CH 3 ) 2 ] 6 Mo 7 O 24 for oxidizing HMF to DFF. The resultant catalyst with high Mo 5+ content presents superior HMF oxidation performance, delivering a > 99% DFF selectivity with complete HMF conversion. Mechanistic studies and density functional theory (DFT) calculations reveal that the Mo 5+ -□ species in the catalyst facilitate O 2 activation and HMF oxidation. Moreover, the catalyst exhibits outstanding catalytic stability during the aerobic oxidation of HMF to DFF.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Xuan Tang,Yugao Wang,Mengni Wei,Xueqin Zhang,Ye Li,Xiaomin Li,Jinping Li,Jiangfeng Yang
Reduction of zeolite crystal size from the micron scale to the nanoscale leads to a significant increase in specific surface area, favoring mass-transfer pathways. Here, we have prepared nanoscale (ca. 30–80 nm) IM-5@100 zeolite (IMF type) by a facile strategy of regulating the amount of Al source in the starting gel, and have investigated its CH 4 /N 2 adsorption and separation properties. We found that on decreasing the amount of Al source, the crystal size of the product changed significantly, decreasing from strips of length about 1 μm to irregular nanocrystals. Compared with micron-sized IM-5@50, the mesopore volume of IM-5@100 was increased fourfold from 0.12 cm 3 /g to 0.49 cm 3 /g, its external surface area was increased from 38 m 2 /g to 118 m 2 /g, and its DFT pore size distribution based on N 2 adsorption/desorption showed a mesopore distribution in the range 5–10 nm. Adsorption kinetics tests showed that nano-IM-5@100 can achieve adsorption equilibrium more swiftly and exhibits better mass-transfer performance. Moreover, IM-5@100 showed good adsorption capacity for CH 4 (17.8 cm 3 /g) and high IAST selectivity (4.7) for CH 4 /N 2 (50:50, v/v). Breakthrough experiments have indicated that IM-5@100 permits efficient practical separation of CH 4 /N 2 .
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