Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 60
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Org Chem ; 89(8): 5320-5327, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38554091

RESUMO

Electromagnetic mill (EMM)-promoted solid-state cascade Heck-type cyclization/decarboxylative coupling of propiolic acid with (Z)-1-iodo-1,6-diene derivate was demonstrated. The reaction was realized via palladium catalysis, which is solvent-free and involves no additional heating. The collision between ferromagnetic rods could not only be a favor to the mixing between the solid substrates and the catalyst system, but also the thermogenic action could accelerate this transformation. More importantly, this EMM strategy realized multiple bond construction under mechanochemical conditions in one pot.

2.
Inorg Chem ; 62(43): 17705-17712, 2023 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-37844205

RESUMO

Accurate matching of the active sites between the host and guest molecules has a great effect on the selective recognition of different but similar guest molecules or different binding abilities toward the same molecule. Herein, a pseudotetrahedral metal-organic cage (MOC, Co-TAP) that contains secondary amino groups designed as guest-interacting sites was achieved. Co-TAP exhibits the selective recognition of uridine over other similar natural molecules via a fluorescent response. However, a reference structure (Co-TOP) with the same configuration was also synthesized by replacing the secondary amine group with an oxygen atom of the ligand, and it reveals the selective recognition of guanosine. In addition, the accurate matching also enables Co-TAP to strongly bind the organic dye as a guest molecule via host-guest interactions, thus facilitating photoinduced electron transfer between the redox catalytic sites in MOC and the excited guest via a pseudointramolecular pathway.

3.
Biosens Bioelectron ; 241: 115710, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37769486

RESUMO

Advanced bioelectronic detection based on the integration of modern optical electronics and biological systems has a broad prospect. The strategy of cathode signal amplification in self-powered photoelectrochemical (PEC) immunosensors with excellent performance is rarely reported in the field of immune analysis. Herein, the work demonstrates a self-powered PEC biosensor formed with BiOI photocathode and WO3/SnS2/ZnS photoanode, and CsPbBr3@COF-V was used as the photocathode signal quenching source for the quantitative monitoring of heart fatty acid binding protein (H-FABP). The high efficiency and stable self-powered biosensor formed not only provides continuous and powerful photocurrent response for bioanalysis through reasonable stepped band structure, but also effectively eliminates the interference of reducing substances. The quenching source CsPbBr3@COF-V greatly affects the photocurrent response due to steric hindrance, weak conductivity, competition with the substrate for dissolved oxygen and excitation light source. And the intervention of this key factor achieves multiple signal amplification effect and opens up an innovative vision for self-powered PEC immunosensor. Taking H-FABP as a representative analyte, the proposed signal amplification self-powered photoelectrochemical presents a broad linear range from 0.0005 to 150 ng/mL with the detection limit of 0.19 pg/mL.

4.
Chemistry ; 29(37): e202300185, 2023 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-37114825

RESUMO

Supramolecular chemistry has become an interdisciplinary discipline of chemistry, physics, and biology. As a huge subunit of supramolecular compounds, the functional metal-organic supramolecular systems with well-defined cavities which are able to accommodate size-suitable guests via benign host-guest behavior, have been known as "metal-organic molecular containers" (MOMCs) and attracted much attentions for their rich chemical properties and wide potential applications in molecular recognition, catalysis, bio-medical and other fields. In particular, the MOMCs with flexible backbones exhibit a unique feature both in the aspect of structural construction and applications, due to the free rotation and self-adaptively of the specific functional groups in the skeletons. In this paper, we review several selected examples of the coordination-driven metal-organic supramolecular systems from the aspects of self-assembly construction to the various applications. The self-assembly strategies, especially the different choice of organic ligands with flexible backbones during the construction, leading to quite diverse configurations compared to the rigid ligands, have been also discussed to show a different perspective of metal-organic system construction.

5.
Inorg Chem ; 62(14): 5565-5575, 2023 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-36989459

RESUMO

Two dimeric {ε-Zn4PMo12}-based metal-organic frameworks (MOFs), [ε-PMo8VMo4VIO34(OH)6Zn4][LO] (SDUT-21, LO = [5-((4'-carboxybenzyl)oxy)isophthalic acid]) and [TBA]3[ε-PMo8VMo4VIO37(OH)3Zn4][LN] (SDUT-22, TBA+ = tetrabutylammonium ion, LN = [5-((4-carboxybenzyl)imino)isophthalic acid]), combining the advantages of polyoxometalates (POMs) and MOFs, were synthesized by the one-pot assembly strategy. The dimeric {ε-Zn4PMo12} units act as nodes that are linked by the flexible ligands and extended into two- or three-dimensional frameworks. The cyclic voltammetry and proton conductivity measurements of SDUT-21 and SDUT-22 were performed and indicated the high electron and proton transfer abilities. These materials also e xhibited the catalytic performance for the synthesis of quinazolinones in the heterogeneous state, and the different binding capacities toward the substrates caused the catalytic activity of SDUT-21 to be higher than that of SDUT-22 under the same conditions. In addition, the used catalysts could be readily recovered for five successive cycles and maintained high catalytic efficiency.

6.
Bioelectrochemistry ; 152: 108405, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36898344

RESUMO

In this work, a label-free electrochemical immunosensor based on popcorn-shaped PtCoCu nanoparticles supported on N- and B-codoped reduced graphene oxide (PtCoCu PNPs/NB-rGO) was constructed to sensitively detect concentration level of ß-Amyloid1-42 oligomers (Aß). The PtCoCu PNPs exhibits excellent catalytic ability due to its popcorn structure which improves the specific surface area and porosity, resulting in more active sites being exposed and fast transport paths for ion/electron. NB-rGO with large surface area and unique pleated structure could disperse PtCoCu PNPs through electrostatic adsorption and formation of d-p dative bonds between the metal ion and pyridinic N of NB-rGO. In addition, the doping of B atoms enhances the catalytic ability of GO enormously and achieves further signal amplification. Besides, both PtCoCu PNPs and NB-rGO are able to fix abundant antibodies through M(Pt, Co, Cu)-N bonds and amide bonds respectively without any other complex processing procedures such as carboxylation, ect. The designed platform achieved the dual amplification of electrocatalytic signal and effectively immobilization of antibodies. Under the optimum conditions, the designed electrochemical immunosensor presented wide linear rang (50.0 fg/mL âˆ¼ 100 ng/mL) and low detection limits (3.5 fg/mL). The results demonstrated that the prepared immunosensor will be promising in sensitive detection of AD biomarkers.


Assuntos
Técnicas Biossensoriais , Grafite , Nanopartículas Metálicas , Técnicas Eletroquímicas/métodos , Técnicas Biossensoriais/métodos , Nanopartículas Metálicas/química , Ouro/química , Imunoensaio/métodos , Grafite/química , Anticorpos , Limite de Detecção
7.
J Colloid Interface Sci ; 632(Pt A): 171-178, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36413943

RESUMO

This research developed a signal amplification strategy to construct a highly sensitive electrochemiluminescent (ECL) aptasensor by incorporating dysprosium metal-organic framework (Dy-MOF) as a co-reaction accelerator (CRA) in gadolinium (Gd) luminescent complex based ECL system. A new Gd(III) complex GdPc(acac) (Pc = phthalocyanine, acac = acetylacetonate) with semi-sandwich structure was rationally selected as ECL emitter, exhibiting excellent luminescence performance owing to the "antenna effect" from the conjugated macrocyclic ligand. For further improving the sensitivity of the ECL biosensor, Dy-MOF was introduced into the ECL system as CRA. The purposive design and configuration of the Dy-MOF structure accelerated the separation and transport of photogenerated charges, and the nanosheets formed by the composite material provided more active sites, which could not only greatly increased the luminophore loading, but also effectively shorten the transport distance of ions and co-reactants. The constructed biosensor showed superior performance to monitor kanamycin within 0.001 pg/mL-1000 ng/mL and a detection limit down to 0.3 fg/mL (S/N = 3). The current work opened up a skillful strategy to amplify ECL singnal, extending the application field of lanthanide complexes and providing valuable information for the future biosensor design.


Assuntos
Disprósio , Estruturas Metalorgânicas , Canamicina , Gadolínio , Indóis
8.
Anal Chem ; 94(45): 15873-15878, 2022 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-36322926

RESUMO

Herein, a novel dual mode detection system of split-type photoelectrochemical (PEC) and visual immunoassay was developed to detect neuron specific enolase (NSE), which achieved simultaneous and reliable NSE detection due to the completely different signal readouts and transduction mechanism. Specifically, specific reactions of antigens and antibodies were performed in 96-microwell plates. Gold nanoparticle (Au NP)-loaded Fe3O4 (Au@Fe3O4) NPs were used as secondary antibody markers and signal regulators, which could produce a blue-colored solution in the presence of 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2 because of its peroxidase-like activity. Therefore, the visual detection of NSE was realized, making the results more intuitive. Meanwhile, the above biological process could also be used as part of the split-type PEC sensing platform. Oxidized TMB and Fe3+ were consumptive agents of the electron donor, which both realized the double quenching of PEC signal generated by the SnO2/MgIn2S4/Zn0.1Cd0.9S composites. Owing to the waterfall band structure, SnO2/MgIn2S4/Zn0.1Cd0.9S composites partially absorb visible light and effectively inhibit the electron-hole recombination, thereby providing significantly enhanced and stable initial signal. On the basis of the multiple signal amplification strategy and the split-type mode, NSE could be sensitively detected with a low detection limit of 14.0 fg·mL-1 (S/N = 3) and a wide linear range from 50.0 fg·mL-1 to 50.0 ng·mL-1.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Ouro/química , Técnicas Eletroquímicas/métodos , Cádmio , Nanopartículas Metálicas/química , Técnicas Biossensoriais/métodos , Limite de Detecção , Peróxido de Hidrogênio/química , Imunoensaio/métodos , Fosfopiruvato Hidratase , Zinco
9.
Acta Chim Slov ; 0(0): 7680, 2022 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-36196796

RESUMO

A series of bi- or mononuclear hexacoordinate iron(III) complexes, [Fe(L)][Fe(bpb)(CN)2]·CH3OH·0.5H2O (1), [Fe(L)][Co(bpb)(CN)2]·CH3OH (2) [(Fe (L))2(4,4'-bipy)](BPh4)2 (3), [Fe(L)(py)](BPh4) (4) and [Fe(L)(dmap)](BPh4) (5) (bpb = 1,2-bis(pyridine-2-carboxamido)benzenate, L = N,N'-bis(2-hydroxybenzyliden)-1,7-diamino-4-azaheptane, dmap = 4-dimethylaminopyridine), have been prepared with the pentadentate Schiff base iron(III) compound as assemble precursor and characterized by element analysis, IR and X-ray diffraction. Single crystal structural determination revealed the neutral cyanide-bridged binuclear entity for complexes 1 and 2 and the cationic di- or mononuclear structure for complexes 3-5 with the positive charge(s) balanced by BPh4- ion(s). The experimental study and theoretical simulation of the magnetic property discovered the ferromagnetic coupling between the Fe(III) ions bridged by cyanide group in complex 1 and the always high spin state of the Fe(III) ion coordinated to the Schiff base ligand in both complexes 1 and 2. The temperature dependent magnetic susceptibility investigation over complexes 3-5 showed the occurrence of the thermo-induced gradual complete spin crossover (SCO) property at about 115, 170 and 200 K, respectively.

10.
J Org Chem ; 87(12): 7995-8004, 2022 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-35671111

RESUMO

A Pd/Et3N·HI-catalyzed intramolecular C-H alkylation of indoles with epoxides was achieved to furnish N-fused indole frameworks (5-, 6-, and 7-membered rings) bearing an alcohol group. The conversion proceeded smoothly in the presence of a catalytic amount of Et3N·HI together with a palladium catalyst and exhibited great functional group tolerance. The employment of Et3N·HI not only avoids the prior preparation of alkyl halide substrates but also is the key to the high chemoselective ring-opening of epoxides. Preliminary mechanism explorations strongly support a radical pathway, and the catalytic cycle was established tentatively according to the mechanism investigation experiments.


Assuntos
Compostos de Epóxi , Indóis , Alquilação , Catálise , Compostos de Epóxi/química , Indóis/química , Paládio/química
11.
Inorg Chem ; 61(8): 3472-3483, 2022 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-35148086

RESUMO

Eight new stable porous lanthanide metal-organic frameworks (Ln-OFs), namely, [Ln2(BPTC)2][(CH3)2NH2]2 [Ln = Ho (1), Eu (2), Gd (3), Dy (4), Er (5), Tm (6), Yb (7), Lu (8)], were prepared by 3,3',5,5'-biphenyltetracarboxylic acid (H4BPTC) and lanthanide ions by solvothermal reactions. Complexes 1-8 show a three-dimensional (3D) 6,6-connected network {412·63}·{48·66·8} topology based on binuclear (Ln2) clusters and feature a one-dimensional curving porous channel occupied by exchangeable dimethylamine cations ([(CH3)2NH2]+) in the 3D anionic frameworks. The occupied [(CH3)2NH2]+ in the anionic channels exhibited excellent ion-exchange ability, which is favorable to Pd2+ and cationic dye adsorption. Consequently, 1-8 were used to load Pd nanoparticles to catalyze the reduction of nitrophenols and adsorb and desorb methyl blue (MB). The catalytic reaction efficiencies of Pd@1-8 were higher than that of Pd/C (5 wt %) in the hydrogenation reaction of p-nitrophenol (p-NP). Moreover, Pd@1 exhibited good cycle stability and achieved nearly 100% p-NP conversion after eight cycles. Meanwhile, compound 1 also exhibited a high adsorption ability of MB, possessing an adsorption capacity of 1.41 g·g-1 (second only to 1.49 g·g-1 reported in the literature) selectively over rhodamine B (RhB) and methyl orange (MO) in aqueous solutions. Remarkably, the skeleton of 1 remained stable after four adsorption-desorption cycles of MB in aqueous solution.

12.
Biosensors (Basel) ; 11(11)2021 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-34821637

RESUMO

Based on the necessity and urgency of detecting infectious disease marker procalcitonin (PCT), a novel unlabeled photoelectrochemical (PEC) immunosensor was prepared for the rapid and sensitive detection of PCT. Firstly, SnO2 porous nanoflowers with good photocatalytic performance were prepared by combining hydrothermal synthesis and calcining. BiOI nanoflowers were synthesized by facile ultrasonic mixed reaction. Ag2S quantum dots were deposited on SnO2/BiOI composites by in situ growth method. The SnO2/BiOI/Ag2S composites with excellent photoelectric properties were employed as substrate material, which could provide significantly enhanced and stable signal because of the energy level matching of SnO2, BiOI and Ag2S and the good light absorption performance. Accordingly, a PEC immunosensor based on SnO2/BiOI/Ag2S was constructed by using the layered modification method to achieve high sensitivity analysis of PCT. The linear dynamic range of the detection method was 0.50 pg·mL-1~100 ng·mL-1, and the detection limit was 0.14 pg·mL-1. In addition, the designed PEC immunosensor exhibited satisfactory sensitivity, selectivity, stability and repeatability, which opened up a new avenue for the analyzation of PCT and further provided guidance for antibiotic therapy.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Imunoensaio , Pró-Calcitonina/análise , Limite de Detecção , Prata , Compostos de Estanho
13.
J Org Chem ; 86(19): 13276-13288, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34541854

RESUMO

The ligand-regulated regiodivergent hydroarylation of the distal double bond of allenamides with aryl boronic acid was achieved in the presence of palladium(II) catalysts, delivering a variety of functionalized enamide with excellent E selectivity and Markovnikov/anti-Markovnikov selectivity. Two possible coordination intermediates were proposed to be responsible for the regiodivergent hydroarylation: (1) The coordination Intermediate I, which was proposed to be formed through the coordination of MeCN, distal double bond, phenyl to palladium, led to the aryl group away from the Intermediate I, inducing excellent E selectivity and anti-Markovnikov selectivity. (2) A switch of regioselectivity to 1,2-Markovnikov hydroarylation was obtained using bidentate phosphine ligand (dppf or Xantphos). The formed coordination Intermediate II led to the N-tether away from the Intermediate II and at the trans position of aryl, resulting in excellent E selectivity and Markovnikov selectivity. Meanwhile, tentative investigation on the mechanism proved that the hydron source of this hydroarylation is more likely to be boronic acid. The transmetallation between aryl boronic acid and palladium catalyst was the initial step of this transformation.

14.
Inorg Chem ; 60(15): 11048-11057, 2021 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-34279097

RESUMO

Self-assembly of [Hg(SeCN)4]2- tetrahedral building blocks, iron(II) ions, and a series of bis-monodentate pyridyl-type bridging ligands has afforded the new heterobimetallic HgII-FeII coordination polymers {Fe[Hg(SeCN)3]2(4,4'-bipy)2}n (1), {Fe[Hg(SeCN)4](tvp)}n (2), {Fe[Hg(SeCN)3]2(4,4'-azpy)2}n (3), {Fe[Hg(SeCN)4](4,4'-azpy)(MeOH)}n (4), {Fe[Hg(SeCN)4](3,3'-bipy)}n (5) and {Fe[Hg(SeCN)4](3,3'-azpy)}n (6) (4,4-bipy = 4,4'-bipyridine, tvp = trans-1,2-bis(4-pyridyl)ethylene, 4,4'-azpy = 4,4'-azobispyridine, 3,3-bipy = 3,3'-bipyridine, 3,3'-azpy = 3,3'-azobispyridine). Single-crystal X-ray analyses show that compounds 1 and 3 display a two-dimensional robust sheet structure made up of infinite linear [(FeL)n]2n+ (L = 4,4'-bipy or 4,4'-azpy) chains linked by in situ formed {[Hg(L)(SeCN)3]2}2- anionic dimeric bridges. Complexes 2 and 4-6 define three-dimensional networks with different topological structures, indicating, in combination with complexes 1 and 3, that the polarity, length, rigidity, and conformation of the bridging organic ligand play important roles in the structural nature of the products reported here. The magnetic properties of complexes 1 and 2 show the occurrence of temperature- and light-induced spin crossover (SCO) properties, while complexes 4-6 are in the high-spin state at all temperatures. The current results provide a new route for the design and synthesis of new SCO functional materials with non-Hofmann-type traditional structures.

15.
Inorg Chem ; 59(22): 16644-16653, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33151057

RESUMO

As a star ligand, the construction of coordination polymers (CPs) based on tetrakis(4-carboxyphenyl)ethylene (H4TCPE) has drawn much attention, due to not only the various coordination configurations but also the intriguing chromophore feature causing aggregation-induced emission (AIE). Herein, by the solvothermal reaction of H4TCPE as connected nodes with lanthanide La(III) salts, the first example of the La(III)-TCPE-based CP (1) has been obtained. The structural analyses indicate that 1 exhibits a 3D framework connected by the sharing carboxylate groups with two kinds of 1D rhombic channels when viewed along the c direction. The photophysical properties of 1 have been explored by luminescence, photoluminescence decay, and quantum yield in the solid state. 1 shows strong luminescence in tetrahydrofuran that was attributed to a "pseudo-AIE process" and sensitive and selective sensing activity of Fe3+ toward metal ions via the obvious luminescent quenching. The sensing mechanism has been investigated and reveals a synergetic effect of the competitive absorption and weak interactions between 1 and Fe3+. Moreover, the high porosity, multiple conjugated π-electrons within the tetrakis(4-carboxyphenyl)ethylene backbone, and the uncoordinated carboxyl oxygen sites in this material also provide the capacity for iodine adsorption. The adsorption experiments indicate that 1 could efficiently remove almost complete I2 from the cyclohexane solution after 24 h contact time with an adsorption capacity of 690 mg/g toward I2.

16.
Acta Crystallogr C Struct Chem ; 76(Pt 9): 856-862, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32887855

RESUMO

The chemistry of transition-metal complexes with unusually high coordination numbers has been of interest because of their application in catalytic and biological systems. Deprotonation of the ionogenic tetradentate ligand 6,6'-bis(1H-tetrazol-5-yl)-2,2'-bipyridine [H2bipy(ttr)2] in the presence of iron(III) and tetra-n-butylammonium bromide, [n-Bu4N]Br, in solution resulted in the synthesis of a rare octacoordinated anionic mononuclear complex, tetra-n-butylammonium bis[6,6'-bis(tetrazol-1-id-5-yl)-2,2'-bipyridine]iron(III) methanol hemisolvate dihydrate, (C16H36N)[Fe(C12H6N10)2]·0.5CH3OH·2H2O or [n-Bu4N][Fe{bipy(ttr)2}2]·0.5CH3OH·2H2O (1), which has been structurally characterized by elemental analysis, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. In 1, the coordination sphere of the iron(III) ion is a distorted bis-disphenoid dodecahedron, in which the eight coordination positions are occupied by eight N atoms from two independent tetradentate [bipy(ttr)2]2- anionic ligands, therefore forming the anionic [Fe{bipy(ttr)2}2]- unit, with the negative charge balanced by a free [n-Bu4N]+ cation. An investigation of the magnetic properties of 1 revealed a gradual incomplete spin-crossover behaviour below 150 K.

17.
Anal Chem ; 92(16): 10935-10939, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32806903

RESUMO

An intramolecular photoelectrochemical (PEC) system is designed from the novel electron donor YYYHWRGWV (Y3-H) peptide ligand for the first time. The bifunctional nonapeptide cannot only rely on the HWRGWV sequence as a site-oriented immobilizer to recognize the crystallizable fragment (Fc) domains of the antibody but also acts as electron donors for PEC generation via three tyrosine (Y) of the N-terminal. The Bi2WO6/AgInS2 heterojunction with a significant visible-light absorption is utilized as a photoelectric generator, and the motivation is ascribed to a proven proposition, namely, that short-wavelength illuminant radiates proteins, causing a decline in bioactivity of immune protein. An innovative biosensor is fabricated using the above strategies for the detection of CYFRA21-1, a biomarker of squamous cell lung carcinoma. This sort of PEC-based sensing platform shows convincing experimental data and could be an effective candidate for clinical application in the future due to their extremely skillful conception.


Assuntos
Antígenos de Neoplasias/sangue , Biomarcadores Tumorais/sangue , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Queratina-19/sangue , Peptídeos/química , Tirosina/química , Anticorpos Imobilizados/química , Anticorpos Imobilizados/imunologia , Antígenos de Neoplasias/imunologia , Biomarcadores Tumorais/imunologia , Bismuto/química , Elétrons , Humanos , Índio/química , Índio/efeitos da radiação , Queratina-19/imunologia , Luz , Limite de Detecção , Fotoquímica/métodos , Pontos Quânticos/química , Pontos Quânticos/efeitos da radiação , Compostos de Prata/química , Compostos de Prata/efeitos da radiação , Compostos de Tungstênio/química , Compostos de Tungstênio/efeitos da radiação
18.
Org Lett ; 22(17): 6734-6738, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32790998

RESUMO

Herein reported is a nickel-catalyzed reductive aryl thiocarbonylation of alkene via thioester group transfer strategy by using simple and readily available thioesters. In contrast to traditional activation of weaker C(acyl)-S bond, the C(acyl)-C bond of thioester was selectively cleaved to enable this reaction under mild conditions. Furthermore, this approach features operational simplicity and broad substrate scope, providing a complementary and practical route for thioester synthesis without requiring toxic thiol or CO gas.

19.
Acta Crystallogr C Struct Chem ; 76(Pt 6): 616-624, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32499460

RESUMO

The solar photocatalysis of water splitting represents a significant branch of enzymatic simulation by efficient chemical conversion and the generation of hydrogen as green energy provides a feasible way for the replacement of fossil fuels to solve energy and environmental issues. We report herein the self-assembly of a CoII-based metal-organic framework (MOF) constructed from 4,4',4'',4'''-(ethene-1,1,2,2-tetrayl)tetrabenzoic acid [or tetrakis(4-carboxyphenyl)ethylene, H4TCPE] and 4,4'-bipyridyl (bpy) as four-point- and two-point-connected nodes, respectively. This material, namely, poly[(µ-4,4'-bipyridyl)[µ8-4,4',4'',4'''-(ethene-1,1,2,2-tetrayl)tetrabenzoato]cobalt(II)], [Co(C30H16O8)(C10H8N2)]n, crystallized as dark-red block-shaped crystals with high crystallinity and was fully characterized by single-crystal X-ray diffraction, PXRD, IR, solid-state UV-Vis and cyclic voltammetry (CV) measurements. The redox-active CoII atoms in the structure could be used as the catalytic sites for hydrogen production via water splitting. The application of this new MOF as a heterogeneous catalyst for light-driven H2 production has been explored in a three-component system with fluorescein as photosensitizer and trimethylamine as the sacrificial electron donor, and the initial volume of H2 production is about 360 µmol after 12 h irradiation.

20.
Acta Crystallogr C Struct Chem ; 76(Pt 5): 412-418, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32367821

RESUMO

With the new semi-rigid V-shaped bidentate pyridyl amide compound 5-methyl-N,N'-bis(pyridin-4-yl)benzene-1,3-dicarboxamide (L) as an auxiliary ligand and the FeII ion as the metal centre, one mononuclear complex, bis(methanol-κO)bis[5-methyl-N,N'-bis(pyridin-4-yl)benzene-1,3-dicarboxamide-κN]bis(thiocyanato-κN)iron(II), [Fe(SCN)2(C19H16N4O2)2(CH3OH)2] (1), and one two-dimensional coordination polymer, catena-poly[[[bis(thiocyanato-κN)iron(II)]-bis[µ-5-methyl-N,N'-bis(pyridin-4-yl)benzene-1,3-dicarboxamide-κ2N:N']] methanol disolvate dihydrate], {[Fe(SCN)2(C19H16N4O2)2]·2CH3OH·2H2O}n (2), were prepared by slow evaporation and H-tube diffusion methods, respectively, indicating the effect of the method of crystallization on the structure type of the target product. Both complexes have been structurally characterized by elemental analysis, IR spectroscopy and single-crystal X-ray crystallography. The single-crystal X-ray diffraction analysis shows that L functions as a monodentate ligand in mononuclear 1, while it coordinates in a bidentate manner to two independent Fe(SCN)2 units in complex 2, with a different conformation from that in 1 and the ligands point in two almost orthogonal directions, therefore leading to a two-dimensional grid-like network. Investigation of the magnetic properties reveals the always high-spin state of the FeII centre over the whole temperature range in 1 and a gradual thermally-induced incomplete spin crossover (SCO) behaviour below 150 K in 2, demonstrating the influence of the different coordination fields on the spin properties of the metal ions. The current results provide useful information for the rational design of functional complexes with different structure dimensionalities by employing different conformations of the ligand and different crystallization methods.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...