Xn:Harmful;69-72-7Relevant academic research and scientific papers
Negative correlations between cultivable and active-yet-uncultivable pyrene degraders explain the postponed bioaugmentation
Jiang, Bo,Chen, Yating,Xing, Yi,Lian, Luning,Shen, Yaoxin,Zhang, Baogang,Zhang, Han,Sun, Guangdong,Li, Junyi,Wang, Xinzi,Zhang, Dayi
, (2021/09/24)
Bioaugmentation is an effective approach to remediate soils contaminated by polycyclic aromatic hydrocarbons (PAHs), but suffers from unsatisfactory performance in engineering practices, which is hypothetically explained by the complicated interactions between indigenous microbes and introduced degraders. This study isolated a cultivable pyrene degrader (Sphingomonas sp. YT1005) and an active pyrene degrading consortium (Gp16, Streptomyces, Pseudonocardia, Panacagrimonas, Methylotenera and Nitrospira) by magnetic-nanoparticle mediated isolation (MMI) from soils. Pyrene biodegradation was postponed in bioaugmentation with Sphingomonas sp. YT1005, whilst increased by 30.17% by the active pyrene degrading consortium. Pyrene dioxygenase encoding genes (nidA, nidA3 and PAH-RHDα-GP) were enriched in MMI isolates and positively correlated with pyrene degradation efficiency. Pyrene degradation by Sphingomonas sp. YT1005 only followed the phthalate pathway, whereas both phthalate and salicylate pathways were observed in the active pyrene degrading consortium. The results indicated that the uncultivable pyrene degraders were suitable for bioaugmentation, rather than cultivable Sphingomonas sp. YT1005. The negative correlations between Sphingomonas sp. YT1005 and the active-yet-uncultivable pyrene degraders were the underlying mechanisms of bioaugmentation postpone in engineering practices.
A functional model for quercetin 2,4-dioxygenase: Geometric and electronic structures and reactivity of a nickel(II) flavonolate complex
Jeong, Donghyun,Sun, Seungwon,Moon, Dohyun,Cho, Jaeheung
, (2021/10/27)
Quercetin 2,4-dioyxgenase (QueD) has been known to catalyze the oxygenative degradation of flavonoids and quercetin. Recent crystallographic study revealed a nickel ion occupies the active site as a co-factor to support O2 activation and catalysis. Herein, we report a nickel(II) flavonolate complex bearing a tridentate macrocyclic ligand, [NiII(Me3-TACN)(Fl)(NO3)](H2O) (1, Me3-TACN = 1,4,7-trimethyl-1,4,7-triazacyclononane, Fl = 3-hydroxyflavone) as a functional model for QueD. The flavonolatonickel(II) complex was characterized by using spectrometric analysis including UV–vis spectroscopy, electrospray ionization mass spectrometer (ESI-MS), infrared spectroscopy (FT-IR) and 1H nuclear magnetic resonance spectroscopy (NMR). The single crystal X-ray structure of 1 shows two isomers with respect to the direction of a flavonolate ligand. Two isomers commonly are in the octahedral geometry with a bidentate of flavonolate and a monodentate of nitrate as well as a tridentate binding of Me3-TACN ligand. The spin state of 1 is determined to be a triplet state based on the Evans' method. Interestingly, electronic configuration of 1 from density functional theory (DFT) calculations revealed that the two singly occupied molecular orbitals (SOMOs) lie energetically lower than the highest (doubly) occupied molecular orbital (HOMO), that is so-called the SOMO-HOMO level inversion (SHI). The HOMO shows an electron density localized in the flavonolate ligand, indicating that flavonolate ligand is oxidized first rather than the nickel center. Thermal degradation of 1 resulted in the formation of benzoic acid and salicylic acid, which is attributed to the oxygenation of flavonolate of 1.
Synthesis of salicylates from anionically activated aromatic trifluoromethyl group
Lin, Chuankai,Liu, Jin-Biao,Wang, Ruixiang,Xie, Huilin
supporting information, (2021/12/22)
An efficient approach to salicylates via a novel transformation of anionically activated aromatic trifluoromethyl group is described. Anionically activated trifluoromethyl group can react with phenols/alcohols under alkaline conditions to afford aryl/alkyl salicylates in high yields. Mechanism studies indicate that the carbonyl oxygen atom of ester is from the H2O in the solvent.
N,O-bidentate ligands-based salicylic spiroborates: A bright frontier of bioimaging
Belskaya, Nataliya P.,Benassi, Enrico,Fomin, Timur O.,Lugovik, Kseniya I.,Minin, Artem S.,Pozdina, Varvara A.,Shevyrin, Vadim A.
, (2022/02/25)
A new series of salicylic spiroborate complexes (SSBs) based on N,O-bidentate 2-(tert-cycloalkylamino)-5-(3-(arylamino)acryloyl)thiophene-3-carbonitriles (NO-SSBs) was obtained and characterized. The optical properties of these compounds were studied and compared with those of analogous BF2-based complexes. The geometries and electronic structures of the NO-SSBs in the ground and excited states, especially their key N–B–O link, were revealed using quantum chemical calculations and compared with the experimental data and photophysical characteristics. Hydrolytic dissociation and photodissociation were considered, and the effects of the NO-SSB structure and nature of the solvent on these reactions were established. Biological investigations elucidated the NO-SSBs ability to penetrate living and fixed cells and selectively accumulate in the endoplasmic reticulum (ER) and Golgi complex. Comparison of the NO-SSBs’ characteristics with those of a commercial dye demonstrated the superiority of their properties and prospects for application in the bio-visualization of the ER and Golgi complex.
Oxygenolysis of a series of copper(ii)-flavonolate adducts varying the electronic factors on supporting ligands as a mimic of quercetin 2,4-dioxygenase-like activity
Anoop, Anakuthil,Dey, Subhasis,Mandal, Sukanta,Podder, Nirmalya
supporting information, p. 4338 - 4353 (2022/04/07)
Four copper(ii)-flavonolate compounds of type [Cu(LR)(fla)] {where LR = 2-(p-R-benzyl(dipyridin-2-ylmethyl)amino)acetate; R = -OMe (1), -H (2), -Cl (3) and -NO2 (4)} have been developed as a structural and functional enzyme-substrate (ES) model of the Cu2+-containing quercetin 2,4-dioxygenase enzyme. The ES model complexes 1-4 are synthesized by reacting 3-hydroxyflavone in the presence of a base with the respective acetate-bound copper(ii) complexes, [Cu(LR)(OAc)]. In the presence of dioxygen the ES model complexes undergo enzyme-type oxygenolysis of flavonolate (dioxygenase type bond cleavage reaction) at 80 °C in DMF. The reactivity shows a substituent group dependent order as -OMe (1) > -H (2) > -Cl (3) > ?NO2 (4). Experimental and theoretical studies suggest a single-electron transfer (SET) from flavonolate to dioxygen, rather than valence tautomerism {[CuII(fla?)] ? [CuI(fla˙)]}, to generate the reactive flavonoxy radical (fla˙) that reacts further with the superoxide radical to bring about the oxygenative ring opening reaction. The SET pathway has been further verified by studying the dioxygenation reaction with a redox-inactive Zn2+ complex, [Zn(LOMe)(fla)] (5).
Electrochemical-induced hydroxylation of aryl halides in the presence of Et3N in water
Ke, Fang,Lin, Chen,Lin, Mei,Long, Hua,Wu, Mei,Yang, Li,Zhuang, Qinglong
supporting information, p. 6417 - 6421 (2021/08/03)
A thorough study of mild and environmentally friendly electrochemical-induced hydroxylation of aryl halides without a catalyst is presented. The best protocol consists of hydroxylation of different aryl iodides and aryl bromides by water solution in the presence of Et3N under air, affording the target phenols in good isolated yields. Moreover, aryl chlorides were successfully employed as substrates. This methodology also provides a direct pathway for the formation of deoxyphomalone, which displayed a significant anti-proliferation effect.
Photocatalytic synthesis of phenols mediated by visible light using KI as catalyst
Huiqin, Wei,Wu, Mei
supporting information, (2021/11/30)
A transition-metal-free hydroxylation of iodoarenes to afford substituted phenols is described. The reaction is promoted by KI under white LED light irradiation and uses atmospheric oxygen as oxidant. By the use of triethylamine as base and solvent, the corresponding phenols are obtained in moderate to good yields. Mechanistic studies suggest that KI and catalysis synergistically promote the cleavage of C-I bond to form free aryl radicals.
An efficient chromium(iii)-catalyzed aerobic oxidation of methylarenes in water for the green preparation of corresponding acids
Jiang, Feng,Liu, Shanshan,Wei, Yongge,Yan, Likai,Yu, Han,Zhao, Wenshu
supporting information, p. 12413 - 12418 (2021/09/28)
A highly efficient method to oxidize methylarenes to their corresponding acids with a reusable Cr catalyst was developed. The reaction can be carried out in water with 1 atm oxygen and K2S2O8as cooxidants, proceeds under green and mild conditions, and is suitable for the oxidation of both electron-deficient and electron-rich methylarenes, including heteroaryl methylarenes, even at the gram level. The excellent result, together with its simplicity of operation and the ability to continuously reuse the catalyst, makes this new methodology environmentally benign and cost-effective. The generality of this methodology gives it the potential for use on an industrial scale. Differing from the accepted oxidation mechanism of toluene, GC-MS studies and DFT calculations have revealed that the key benzyl alcohol intermediate is formed under the synergetic effect of the chromium and molybdenum in the Cr catalyst, which can be further oxidized to afford benzaldehyde and finally benzoic acid.
Practical scale up synthesis of carboxylic acids and their bioisosteres 5-substituted-1H-tetrazoles catalyzed by a graphene oxide-based solid acid carbocatalyst
Mittal, Rupali,Kumar, Amit,Awasthi, Satish Kumar
, p. 11166 - 11176 (2021/03/31)
Herein, catalytic application of a metal-free sulfonic acid functionalized reduced graphene oxide (SA-rGO) material is reported for the synthesis of both carboxylic acids and their bioisosteres, 5-substituted-1H-tetrazoles. SA-rGO as a catalytic material incorporates the intriguing properties of graphene oxide material with additional benefits of highly acidic sites due to sulfonic acid groups. The oxidation of aldehydes to carboxylic acids could be efficiently achieved using H2O2as a green oxidant with high TOF values (9.06-9.89 h?1). The 5-substituted-1H-tetrazoles could also be effectively synthesized with high TOF values (12.08-16.96 h?1). The synthesis of 5-substituted-1H-tetrazoles was corroborated by single crystal X-ray analysis and computational calculations of the proposed reaction mechanism which correlated well with experimental findings. Both of the reactions could be performed efficiently at gram scale (10 g) using the SA-rGO catalyst. SA-rGO displays eminent reusability up to eight runs without significant decrease in its productivity. Thus, these features make SA-rGO riveting from an industrial perspective.
Cu(II)-Based Ionic Liquid Supported on SBA-15 Nanoparticles Catalyst for the Oxidation of Various Alcohols into Carboxylic Acids in the Presence of CO2
Chen, Yanwu,Hou, Dejian,Lin, Litian,Peng, Qi,Sadeghzadeh, Seyed Mohsen
, (2021/07/26)
In this paper, we have produced carboxylic acids by the oxidation of various alcohols in the presence of CO2 using SBA-15/IL supported Cu(II) (SBA-15/IL/Cu(II)) as nanocatalyst. The obtained products showed to have excellent yields by taking into account of SBA-15/IL/Cu(II) nanocatalyst. In addition, the analysis of EDX, SEM, TGA, TEM, XPS, and FT-IR showed the heterogeneous structure of SBA-15/IL/Cu (II) catalyst. It is determined that, after using SBA-15 excess, the catalytic stability of the system was enhanced. Moreover, hot filtration provided a full vision in the heterogeneous catalyst nature. The recycling as well as reuse of the catalyst were studied in cases of coupling reactions many times. Moreover, we have studied the mechanism of the coupling reactions. Graphic Abstract: [Figure not available: see fulltext.]
