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1.
Inorg Chem ; 62(39): 16170-16181, 2023 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-37722103

RESUMO

In response to the growing concern for environmental pollution, two lanthanide compounds {[Ln(L)(H2O)]·4H2O}n (where Ln = Tb and Gd, H3L = 1-amino-2,4,6-benzene tricarboxylic acid) were synthesized using a -NH2 modified ligand and systematically characterized. Both compounds exhibit remarkable fluorescence response, adsorption of CrO42- ions, and photocatalytic degradation properties, as well as exceptional acid-base and thermal stability. Remarkably, the pH-dependent 1-Tb exhibits exceptional performance as a fluorescent probe for detecting Fe3+ and CrO42-/Cr2O72- ions in aqueous solutions, while also serving as a ratiometric fluorescent probe for the detection of Cr3+, offering rapid response, high sensitivity, selectivity, and recoverability advantages in application. Moreover, 1-Tb exhibits excellent detection capabilities and displays effective adsorption of CrO42- ions, with a maximum adsorption capacity of 230.71 mg/g. On the other hand, 1-Gd exhibits superior performance compared to 1-Tb in the photocatalytic degradation of antibiotics. The degradation mechanism is further elucidated by conducting experiments with DFT theoretical calculations.

2.
Angew Chem Int Ed Engl ; 62(43): e202312698, 2023 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-37682089

RESUMO

The first coordination-saturated buckyball with a C60 molecule totally encased in an icosidodecahedral Cu30 in a (µ30 -(η2 )30 )-fashion, namely C60 @Cu30 @Cl36 N12 , has been successfully realized by a C60 -templated assembly. The 48 outmost coordinating atoms (36Cl+12N) comprise a new simple polyhedron that is described by a ccf topology. Charge transfer from (CuI , Cl) to C60 explains the expansion of the light absorption up to 700 nm, and accounts for an ultrafast photophysical process that underpins its high photothermal conversion efficiency. This work makes a giant step forward in exohedral metallofullerene (ExMF) chemistry.

3.
Inorg Chem ; 61(28): 10624-10628, 2022 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-35776662

RESUMO

Polymeric {Cu6[(µ3-η2:η2:η2)2-C60](FPz)6Cl·3C6H5Cl}∞ [FPz = 4-(trifluoromethyl)pyrazolate], synthesized solvothermally with chlorobenzene as the solvent, is a doubly-connecting trans bis-adduct hexanuclear cuprofullerene that has copper in mixed valence. The compound is an example of a metallofullerene having semiconductivity character.

4.
Angew Chem Int Ed Engl ; 60(41): 22368-22375, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34383376

RESUMO

The salts {[Ln2 Ln*(Hhmq)3 (OAc)3 (hfac)2 ]+ [Ln*(hfac)3 (OAc)(MeOH)]- } (Hhmq=2-methanolquinolin-8-oxide, hfac=hexafluoroacetylacetonate; Ln, Ln*=Er, Gd, Yb) feature a discrete heteronuclear cation consisting of two types of lanthanide atoms. The quinolinoxy O-atom serves as a µ2 -bridge to two Ln atoms and as a µ3 -bridge to all three atoms, with metal⋅⋅⋅metal distances being around 3.7 Å. For 1 ([Yb2 Er]+ ), near-infrared downshifted luminescence is switched to competitive upconversion luminescence upon irradiation by a 980 nm laser under an extremely low excitation power (0.288 W cm-2 ) through introduction of fluoride ions. The stability of 1 after addition of fluoride was confirmed by powder X-ray diffraction and multistage mass spectrometry, associated with the 1 H NMR of 6 ([La2 Eu]+ ). More importantly, the at least 20-fold enhancement of the quantum yield in non-deuterated solvents at room temperature under low power densities (2 W cm-2 ) is the highest among the few molecular examples reported.

5.
J Am Chem Soc ; 142(13): 5943-5947, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32187495

RESUMO

Exohedral cuprofullerenes with 6-, 12-, or 24-nuclearity were obtained by utilizing fluorocarboxylic/dicarboxylic acid under solvothermal conditions. The 24-nuclear molecule presents a C60@Cu24 core-shell structure with a rhombicuboctahedron Cu24 coated on the C60 core, representing the highest nuclearity in metallofullerene. The resultant complexes show an efficient absorption of visible light as opposed to the pristine C60. TD-DFT calculations revealed the charge transfer from Cu(I) and O atoms to the fullerene moiety dominates the photophysical process.

6.
J Am Chem Soc ; 140(37): 11569-11572, 2018 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-30141923

RESUMO

Chiroptical activity is observed from an achiral adenine-containing metal-organic framework (MOF) named ZnFDCA. Such a seemingly counterintuitive phenomenon can, in fact, be predicted by the intrinsic crystal symmetry of 4̅2 m point group. Although theoretically allowed, examples of optically active achiral crystals are extremely rare. ZnFDCA is the first reported achiral MOF showing optical activity, as demonstrated by a pair of circular dichroism signals with opposite signs and enhanced intensity. Moreover, simply through adding an amino substituent to adenine, the chiroptical activity, as well as nonlinear optical activity, of the analogous MOF, namely ZnFDCA-NH2, disappears due to diverse packing pattern giving rise to centrosymmetric crystal symmetry.


Assuntos
Adenina/química , Estruturas Metalorgânicas/química , Óptica e Fotônica , Tamanho da Partícula
7.
Chemistry ; 23(32): 7748-7754, 2017 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-28378888

RESUMO

A series of new lanthanide coordination supramolecular networks (CSNs) based on nalidixic acid (HNA) ligand were designed and synthesized. Their crystal structures were determined by single-crystal XRD techniques. Thin films of these compounds were first successfully deposited on indium tin oxide (ITO) glass through one-step electrophoretic deposition under mild conditions. The europium CSN film exhibits intense red emission and can act as a highly sensitive luminescent sensor for H2 PO4- anions and adenosine triphosphate (ATP) in aqueous solution. The limits of detection of H2 PO4- and ATP can achieve 0.68 and 1.9 µm respectively. The sensing mechanism was further explored through fluorescence and UV techniques. The fabricated sensor also showed excellent selectivity towards these phosphates in the presence of other coexisting ions (F- , Cl- , Br- , I- , SO4- , CO32- , NO3- , and AcO- ) without interference. Moreover, we demonstrated the feasibility of using this sensor to detect ATP in bovine serum samples, suggesting the potential value of application in real biosystems.

8.
Inorg Chem ; 56(21): 13446-13455, 2017 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-29023107

RESUMO

Six daughter complexes based on two-dimensional (2-D) luminescent Cu4I4-Cu3Pz3 (Pz = pyrazolate) coordination networks, which exhibit an uncommon Cu4I4L3L' (L = pyridine; L' = acetonitrile, pyridine, pyrazine, 1,4-diazabicyclo[2.2.2]octane, triphenylphosphine, none) local configuration, were prepared through a postsynthetic modification method starting from a parent complex (L' = NH3). This work has successfully implemented the single-site substitution of Cu4I4-based coordination frameworks, which have rarely been reported for isolated Cu4I4-type compounds, by taking advantage of the solvent-assisted ligand substitution strategy recently developed in metal-organic framework (MOF) chemistry. Such a procedure not only resulted in the variation of local geometry in the Cu4I4 units but also led to interlayer network displacement and entanglement. Particularly, an interesting topological transformation (from 2-D to 2-D → 3-D interpenetration) occurred when linear bidentate linkers (e.g., pyrazine and 1,4-diazabicyclo[2.2.2]octane) are inserted between the 2-D layers. Moreover, the variation in the L' sites can effectively tune the emission colors, ranging from green to orange (λemmax 540-605 nm at room temperature). The photoluminescence origins are tentatively assigned to be a mixture of 3MLCT and 3XLCT, different from that of the well-studied isolated Cu4I4-type complexes.

9.
Proc Natl Acad Sci U S A ; 111(51): 18138-43, 2014 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-25425666

RESUMO

The Pictet-Spengler (PS) reaction constructs plant alkaloids such as morphine and camptothecin, but it has not yet been noticed in the fungal kingdom. Here, a silent fungal Pictet-Spenglerase (FPS) gene of Chaetomium globosum 1C51 residing in Epinephelus drummondhayi guts is described and ascertained to be activable by 1-methyl-L-tryptophan (1-MT). The activated FPS expression enables the PS reaction between 1-MT and flavipin (fungal aldehyde) to form "unnatural" natural products with unprecedented skeletons, of which chaetoglines B and F are potently antibacterial with the latter inhibiting acetylcholinesterase. A gene-implied enzyme inhibition (GIEI) strategy has been introduced to address the key steps for PS product diversifications. In aggregation, the work designs and validates an innovative approach that can activate the PS reaction-based fungal biosynthetic machinery to produce unpredictable compounds of unusual and novel structure valuable for new biology and biomedicine.


Assuntos
Alcaloides/biossíntese , Chaetomium/metabolismo , Chaetomium/genética , Genes Fúngicos
10.
Photochem Photobiol Sci ; 15(6): 744-51, 2016 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-27161911

RESUMO

A series of new lanthanide complexes, formulated as [Ln2(DCSAL)3(H2O)11]·3DCSAL·4H2O [Ln = Eu (1), Gd (2) and Tb (3); DCSAL = 3,5-dichlorosalicylate], have been synthesized and characterized by single crystal X-ray analysis. They are dinuclear clusters and form a 3D supramolecular network viaπ-π stacking and halogen bonding interactions. 3 exhibits strong Tb characteristic emission, whose quantum yield is as high as 38%. Due to binding with Cu(2+) ions via its Lewis acid-base interactions, 3 displayed a high selectivity and sensitivity for Cu(2+) detection based on Tb(3+) emission quenching. The possible quenching mechanism was further proved to be a static quenching mechanism by Stern-Volmer plots and UV-vis spectrum. More importantly, the binding constant between 3 and Cu(2+) is also calculated by the Benesi-Hildebrand method, which is helpful for quantitative analysis.


Assuntos
Cobre/química , Elementos da Série dos Lantanídeos/química , Luminescência , Cátions Bivalentes/química , Halogênios/química , Elementos da Série dos Lantanídeos/síntese química , Estrutura Molecular , Processos Fotoquímicos , Análise Espectral , Difração de Raios X
11.
Mol Divers ; 20(3): 627-38, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27003393

RESUMO

Novel tricyclic keto diesters have been synthesized by a one-pot three-component procedure via DABCO-catalyzed domino Knoevenagel-Michael addition reactions. Also, an efficient four-component reaction for the synthesis of another new group of tricyclic keto diesters has been developed via domino Knoevenagel-intramolecular oxo-Diels-Alder reactions. A selective thermal isomerization of the synthesized chromenes to fumarates is also described. X-ray analyses confirm unambiguously the structures of the products.


Assuntos
Benzopiranos/síntese química , Compostos Heterocíclicos/síntese química , Benzopiranos/química , Catálise , Ciclização , Reação de Cicloadição , Compostos Heterocíclicos/química , Estrutura Molecular , Estereoisomerismo
12.
Pharm Biol ; 54(9): 1649-55, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26866457

RESUMO

Context Dodonaea viscosa (L.) Jacq (Sapindaceae) has been used in traditional medicine as antimalarial, antidiabetic and antibacterial agent, but further investigations are needed. Objective This study determines the antioxidant and anticholinesterase activities of six compounds (1-6) and two crystals (1A and 3A) isolated from D. viscosa, and discusses their structure-activity relationships. Materials and methods Antioxidant activity was evaluated using six complementary tests, i.e., ß-carotene-linoleic acid; DPPH(•), ABTS(•+), superoxide scavenging, CUPRAC and metal chelating assays. Anticholinesterase activity was performed using the Elman method. Results Clerodane diterpenoids (1 and 2) and phenolics (3-6) - together with three crystals (1A, 3A and 7A) - were isolated from the aerial parts of D. viscosa. Compound 3A exhibited good antioxidant activity in DPPH (IC50: 27.44 ± 1.06 µM), superoxide (28.18 ± 1.35% inhibition at 100 µM) and CUPRAC (A0.5: 35.89 ± 0.09 µM) assays. Compound 5 (IC50: 11.02 ± 0.02 µM) indicated best activity in ABTS assay, and 6 (IC50: 14.30 ± 0.18 µM) in ß-carotene-linoleic acid assay. Compounds 1 and 3 were also obtained in the crystal (1A and 3A) form. Both crystals showed antioxidant activity. Furthermore, crystal 3A was more active than 3 in all activity tests. Phenol 6 possessed moderate anticholinesterase activity against acetylcholinesterase and butyrylcholinesterase enzymes (IC50 values: 158.14 ± 1.65 and 111.60 ± 1.28 µM, respectively). Discussion and conclusion This is the first report on antioxidant and anticholinesterase activities of compounds 1, 2, 5, 6, 1A and 3A, and characterisation of 7A using XRD. Furthermore, the structure-activity relationships are also discussed in detail for the first time.


Assuntos
Antioxidantes/farmacologia , Inibidores da Colinesterase/farmacologia , Compostos Fitoquímicos/farmacologia , Sapindaceae , Acetilcolinesterase/metabolismo , Antioxidantes/isolamento & purificação , Benzotiazóis/química , Compostos de Bifenilo/química , Butirilcolinesterase/metabolismo , Quelantes/isolamento & purificação , Quelantes/farmacologia , Inibidores da Colinesterase/isolamento & purificação , Cristalografia por Raios X , Sequestradores de Radicais Livres/isolamento & purificação , Sequestradores de Radicais Livres/farmacologia , Ácido Linoleico/química , Estrutura Molecular , Compostos Fitoquímicos/isolamento & purificação , Fitoterapia , Picratos/química , Plantas Medicinais , Sapindaceae/química , Relação Estrutura-Atividade , Ácidos Sulfônicos/química , Superóxidos/química , beta Caroteno/química
13.
Chemistry ; 21(49): 17951-8, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26489982

RESUMO

Three solid materials, [Pb(HL)(SCN)2 ]⋅CH3 OH (1), [Pb(HL)(SCN)2 ] (2), and [Pb(L)(SCN)]n (3), were obtained from Pb(SCN)2 and an unsymmetrical bis-pyridyl hydrazone ligand that can act both as a bridging and as a chelating ligand. In all three the lead center is hemidirectionally coordinated and is thus sterically optimal for participation in tetrel bonding. In the crystal structures of all three compounds, the lead atoms participate in short contacts with thiocyanate sulfur or nitrogen atoms. These contacts are shorter than the sums of the van der Waals radii (3.04-3.47 Šfor Pb⋅⋅⋅S and 3.54 Šfor Pb⋅⋅⋅N) and interconnect the covalently bonded units (monomers, dimers, and 2D polymers) into supramolecular assemblies (chains and 3D structures). DFT calculations showed these contacts to be tetrel bonds of considerable energy (6.5-10.5 kcal mol(-1) for Pb⋅⋅⋅S and 16.5 kcal mol(-1) for Pb⋅⋅⋅N). A survey of structures in the CSD showed that similar contacts often appear in crystals of Pb(II) complexes with regular geometries, which leads to the conclusion that tetrel bonding plays a significant role in the supramolecular chemistry of Pb(II) .

14.
Chemistry ; 21(51): 18534-8, 2015 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-26459298

RESUMO

A dinuclear gold(I) pyrrolidinedithiocarbamato complex (1) with a bidentate carbene ligand has been constructed and shows potent in vitro cytotoxic activities towards cisplatin-resistant ovarian cancer cells A2780cis. Its rigid scaffold enables a zinc(II)-based metal-organic framework (Zn-MOF) to be used as a carrier in facilitating the uptake and release of 1 in solutions. Instead of using a conventional dialysis approach for the drug-release testing, in this study, a set of transwell assay-based experiments have been designed and employed to examine the cytotoxic and antimigratory activities of 1@Zn-MOF towards A2780cis.


Assuntos
Cisplatino/química , Compostos de Ouro/química , Compostos de Ouro/toxicidade , Ouro/química , Neoplasias Ovarianas/química , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/patologia , Tiocarbamatos/química , Zinco/química , Linhagem Celular , Feminino , Humanos , Ligantes , Estrutura Molecular
15.
Inorg Chem ; 54(8): 3719-21, 2015 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-25849722

RESUMO

Herein, two stable lead(II) molecular-bowl-based metal-organic frameworks and their micro- and nanosized forms with open metal sites were presented. These materials could act as Lewis acid catalysts to cyanosilylation reaction. Moreover, the catalytic performances are size-dependent, with the catalyst with nanosized form being 1 order of magnitude more efficient than those with micro- and millisized forms.

16.
Mol Divers ; 19(3): 501-10, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25900668

RESUMO

Various 2-[5-(aryl)-1,2,4-oxadiazol-3-yl]quinazolin-4(3H)-ones have been synthesized from the reaction of diaminoglyoxime-based nitrones with methyl 2-aminobenzoate or 2-aminobenzamide in the presence of acetic acid at 100 °C. The reaction was extended as a one-pot three-component approach starting from diaminoglyoxime, aldehyde and methyl 2-aminobenzoate.


Assuntos
Óxidos de Nitrogênio/química , Oximas/química , Quinazolinonas/química , Quinazolinonas/síntese química , Aldeídos/química , Aminobenzoatos/química , Técnicas de Química Sintética , Modelos Moleculares , Conformação Molecular
17.
Planta Med ; 81(2): 145-51, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25519918

RESUMO

The endophytic fungus Guignardia mangiferae isolated from Ilex cornuta leaves was shown to produce a family of meroterpenes with toll-like receptor 3 regulating activity (1-9), of which 1-3 possessed new structures. The absolute stereochemistry of 1-3 was assigned through a combination of nuclear magnetic resonance experiments, chemical derivation, CD spectra, and single-crystal X-ray diffraction analyses (CuK α ). The precursor labeled cultivation suggests that these meroterpenes are most likely assembled through terpenoid-shikimate pathways. Moreover, meroterpenes 1-3, 5-7, and 9 selectively upregulate, but 4 and 8 downregulate the toll-like receptor 3 expression in mouse dendritic cells at 10.0 µM.


Assuntos
Ascomicetos/química , Ilex/microbiologia , Terpenos/farmacologia , Receptor 3 Toll-Like/metabolismo , Endófitos , Regulação da Expressão Gênica , Estrutura Molecular , Folhas de Planta/microbiologia , Terpenos/química , Terpenos/isolamento & purificação , Receptor 3 Toll-Like/química
18.
J Am Chem Soc ; 136(27): 9532-5, 2014 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-24941436

RESUMO

We observed an unusual reversible aggregation process showing stimuli-responsive structural dynamics and optical changes attributed to the formation of a sandwich-like Au3-Ag-Au3 cluster, which can be synthesized through both solution and mechanochemical methods. Unlike many other heteronuclear gold-silver clusters, the affinity of two cyclic Au3 complexes and a Ag(I) ion is solely bound by ligand unsupported Au-Ag bonding. The assembly/disassembly behavior, further forming nanoaggregates, is controllable by adjusting the concentration of the solution. In the solid state, the insertion of Ag(I) ion can be implemented through a mechanochemical approach, accompanied by visual color changes and reversible luminochromism. Furthermore, an uncommon solid-liquid extraction is demonstrated, showing the uniqueness of this labile Au-Ag metallophilicity and hinting at the possibility of manipulating a bonding process through a heterogeneous route.

19.
Org Biomol Chem ; 12(34): 6545-8, 2014 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-25051017
20.
Mol Divers ; 18(4): 769-76, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25115630

RESUMO

The synthesis of bis(1,2,4-oxadiazoles), 1,2,4-oxadiazolyl-quinazolines, and 1,2,4-oxadiazolyl-benzothiazinones has been investigated by the reaction of diaminoglyoxime with various ketones and methyl 2-aminobenzoate, 2-amino-5-chlorophenyl)(phenyl)methanone, and 2-mercapto benzoic acid in acetic acid either a catalyst or solvent at 100 °C.


Assuntos
Oxidiazóis/síntese química , Oximas/química , Quinazolinas/síntese química , Técnicas de Química Sintética , Modelos Moleculares , Estrutura Molecular
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