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1.
Angew Chem Int Ed Engl ; : e202409109, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38780121

RESUMO

Two closely related yet distinctly different cationic clusters, [Dy52Ni44(HEIDA)36(OH)138(OAc)24(H2O)30]10+ (1) and [Dy112Ni76(HEIDA)44(EIDA)24(IDA)4(OH)268(OAc)48(H2O)44]4+ (2) (HEIDA=N-(2-hydroxyethyl)iminodiacetate), each featuring a multi-shell core of Platonic and Archimedean polyhedra, were obtained. Depending on the specific conditions used for the co-hydrolysis of Dy3+ and Ni2+, the product can be crystallized out as one particular type of cluster or as a mixture of 1 and 2. How the reaction process was affected by the amount of hydrolysis-facilitating base and/or by the reaction temperature and duration was investigated. It has been found that a reaction at a high temperature and/or for an extended period favors the formation of the compact and thermodynamically more stable 1, while a brief reaction with a large amount of the base is good for the kinetic product 2. By tuning these intertwining conditions, the reaction can be regulated toward a particular product.

2.
J Am Chem Soc ; 146(14): 9506-9511, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38557065

RESUMO

Clusters showing a giant magnetocaloric effect (MCE) are of interest as molecular coolants for magnetic refrigeration. Herein, we report two heterometallic clusters, denoted as Gd152Ni14@Cl24 and Sm152Ni8, just to highlight their inorganic core motifs, obtained by ligand-controlled co-hydrolysis of Ni2+ and Ln3+ (Ln = Gd, Sm) in the presence of N-(2-hydroxyethyl)iminodiacetic acid (H2HEIDA). Both clusters display fascinating cubic Tinkertoy-like structures, with the core motifs being built of multiple metallic shells of Platonic and Archimedean polyhedra. The isothermal magnetic entropy change─a direct measurement of MCE─was determined to be 52.65 J·kg-1·K-1 at 2.5 K and 7.0 T for the Gd-containing cluster; this value is the highest known for any molecular clusters so far reported.

3.
Dalton Trans ; 51(33): 12549-12557, 2022 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-35916552

RESUMO

It is necessary to decrease the application cost of luminescent Ln-MOF sensors to develop multiple functionalities. The ingenious design of ligands and the rational doping of Ln3+ ions are the main approaches to endowing Ln-MOFs with more functionalities. "V" shaped ligands can cause diamond pore channels commonly. "OC-NH" groups as hydrogen bonding sites not only can participate in supramolecular self-assembly but also can achieve molecular recognition. Based on the above considerations, a "V" shaped ligand, H2L, with a suitable triplet state and "OC-NH" groups was designed and synthesized firstly. And the Ln-MOFs (Ln = Eu, Gd, Tb) were obtained by solvothermal reactions. Single crystal X-ray diffraction showed that Ln-MOFs had two types of diamond pore channels where "OC-NH" groups adhered to the surface. "OC-NH" groups not only played an important role in the stacking process of 2D coordinated layers but also can reduce the non-radiative transition resulting from molecular vibration. The Eu-MOF and Tb-MOF not only can emit strong "f-f" transitions characteristic of luminescence but also can detect o-phenylenediamine (OPD) and p-phenylenediamine (PPD) by luminescence quenching. Besides, EuxTb1-x-MOFs (x = 0.02, 0.05, 0.1) were synthesized and can be used as ratio luminescence thermometers whose maximum relative sensitivities were 1.19% K-1 at 400 K. It is pointed out specifically that the relationship between the relative sensitivities and the Eu3+ content was studied. What's more, our work not only developed a series of Ln-MOF luminescent sensors by designing functional ligands and doping Ln3+ rationally but also provided valuable knowledge for the following work.

4.
Angew Chem Int Ed Engl ; 61(33): e202205385, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35503751

RESUMO

The ability to construct complex molecular architectures with precise control is critical for realizing molecule-based materials and functions. Using the assembly of a 60-metal complex of ErIII with histidine as an example, we demonstrate the rational assembly of otherwise synthetically elusive polynuclear lanthanide hydroxide clusters directed by the combined set of I- and CO3 2- as templates. We succeeded in the stepwise transformation starting from Er12 to Er60 by way of two key intermediates Er34 and Er48 . The Er12 , Er34 , and Er48 core motifs represent respectively 1/6, 1/2, and 3/4 of the complete sodalite cage of Er60 . This work, representing a rare example of rationally constructing high-nuclearity lanthanide clusters guided by judiciously chosen templates, is expected to stimulate more future efforts for the controllable synthesis of complex molecular or supramolecular architectures with unprecedented structural sophistication and possibly useful properties.

5.
ACS Omega ; 7(9): 8141-8149, 2022 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-35284717

RESUMO

Silver complexes with proteinogenic amino acid ligands are of interest for biomedical and antimicrobial applications. In this work, we obtained {[Ag7(l-his)4](NO3)3·3H2O}0.2{[Ag8(l-his)4(H2O)2](NO3)4·3H2O}0.8 (1) and {[Ag7(d-his)4](NO3)3·3H2O}0.2{[Ag8(d-his)4(H2O)2](NO3)4·3H2O}0.8 (2), which represent the first example of any Ag-exclusive complex featuring a cluster-type core motif and with only proteinogenic amino acid ligands. Upon immersion into acetonitrile, an interesting single-crystal-to-single-crystal transformation occurred to produce a new cluster complex of the formula [Ag8(l-his)4(NO3)(H2O)](NO3)3 (3). Using a racemic mixture of histidine, the reaction under otherwise identical conditions led to the production of the second example of a three-dimensional (3D) network structured Ag-exclusive complex with only a proteinogenic amino acid ligand. Compared with other Ag-histidine complexes in the literature, the significance of reaction conditions, particularly the Ag/histidine ratio and pH of the reaction mixture, is revealed. Temperature-dependent emission of 1 and 2 at 440 nm characteristic of silver-philophilic interactions was also observed.

6.
Dalton Trans ; 49(29): 10270-10277, 2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32672283

RESUMO

A series of novel asymmetry 3d-4f helicates Zn3LnL4 (H2L = N-(2-((3,5-di-tert-butyl-2-hydroxybenzylidene)amino)ethyl)-2-hydroxybenzamide, Ln = Dy(1), Gd(2), Er(3)) were successfully constructed via selective incorporation of groups with different coordination capabilities. These helicates with the well-defined conformation demonstrate high catalytic efficiency in converting CO2 to cyclic carbonates under mild conditions. Particularly, Zn3ErL4 showed superior catalytic performance with high catalytic activity (TOF up to 38 000 h-1) and extraordinary selectivity (up to 99%) across the wide substrate scope. Meanwhile, these 3d-4f helicates showed stable catalytic performance without being influenced by the moisture and air. The results presented herein highlight an important consideration for constructing heterometallic and asymmetric complexes for catalyzing CO2 conversion.

7.
Dalton Trans ; 47(21): 7159-7165, 2018 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-29770424

RESUMO

Two series of anion-induced 3d-4f luminescent clusters ZnII2LnIII2L4 (LnIII = Eu3+, Tb3+, Er3+, Yb3+, Nd3+) and ZnII4LnIII2L4 (LnIII = Tb3+, Nd3+) based on µ3-OH group were synthesized and characterized. The difference in anions not only leads to significant structural changes, but also changes the luminescent properties of the 3d-4f coordination clusters. These complexes show excellent catalytic performance for CO2 conversion to obtain cyclic carbonates with wide substrate scopes and high selectivity under mild conditions. Turnover numbers were up to 9000, and turnover frequencies obtained were 660 h-1. The ligand is simple and the complexes are easily obtained even on a large scale. Moreover, these complexes also feature lanthanide-characterized luminescence both in visible and near infrared regions with relatively long luminescence lifetimes and high quantum yields, suggesting promising multifunctional applications.

8.
Chemistry ; 23(41): 9804-9811, 2017 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-28439992

RESUMO

A series of unique homochiral lanthanide tetranuclear quadruple-stranded helicates have been self-assembled controllably by using the intrinsic advantages of chiral bridging ligands, (S)-H2 L and (R)-H2 L, and lanthanide ions with high coordination numbers. The self-assembly process of these chiral helicates not only ensures the structural stability and quadruple-stranded feature of lanthanide cluster in the solid state and solution, but also achieves effective transfer and amplification of the chirality code from the ligand to a higher supramolecular level. Moreover, through using optical rotation, circular dichroism spectra analysis, and luminescence measurements, we demonstrate that these chiral lanthanide helicates could serve as sensitive and multi-responsive sensors to recognize and detect F- anions based on the change of chiral signal and NIR luminescence simultaneously, which represents a meaningful exploration for developing functional lanthanide-based polynuclear clusters.

9.
Chemistry ; 22(52): 18769-18776, 2016 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-27709697

RESUMO

A novel luminescent microporous lanthanide metal-organic framework (Ln-MOF) based on a urea-containing ligand has been successfully assembled. Structural analysis revealed that the framework features two types of 1D channels, with urea N-H bonds projecting into the pores. Luminescence studies have revealed that the Ln-MOF exhibits high sensitivity, good selectivity, and a fast luminescence quenching response towards Fe3+ , CrVI anions, and picric acid. In particular, in the detection of Cr2 O72- and picric acid, the Ln-MOF can be simply and quickly regenerated, thus exhibiting excellent recyclability. To the best of our knowledge, this is the first example of a multi-responsive luminescent Ln-MOF sensor for Fe3+ , CrVI anions, and picric acid based on a urea derivative. This Ln-MOF may potentially be used as a multi-responsive regenerable luminescent sensor for the quantitative detection of toxic and harmful substances.

10.
Dalton Trans ; 45(47): 18859-18866, 2016 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-27722522

RESUMO

A functional amide-type pincer ligand was designed and synthesized, which could effectively capture Tb3+ ions to form a phosphorescence complex-based chemosensor Tb-1. The chemosensor could further coordinate with Pb2+ ions and display a turn-on phosphorescence response. This sensing process was analyzed in detail by steady-state luminescence spectroscopy, time-resolved luminescence spectroscopy, electron microscopy and dynamic light scattering, which suggest that the formation of Pb2+-induced hydroxide nanoclusters can adjust the optical signal of the external luminescence compound by embedment and fixation of Tb3+ complexes. Furthermore, Tb-1 could effectively eliminate the signal interference from the short-lived fluorescence and improve the signal-to-noise ratio to increase the accuracy of the detection for Pb2+. An understanding of the recognition mechanism of the Tb3+ complex-based chemosensor and the application of the characteristic spectra of lanthanide ions might be able to provide more opportunities to develop highly selective optical chemosensors.

11.
Chem Commun (Camb) ; 52(29): 5124-7, 2016 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-26987655

RESUMO

A semi-rigid ligand could capture effectively Yb(3+) ions to form a stable Yb(3+) complex and provide a potential cavity to accommodate alkali metal ions. Only K(+) ions could induce the Yb(3+) complex to form a 1D coordination polymer and promote the in situ formation of an NIR membrane coated with bigger Yb(3+) complex crystallites under mild conditions.


Assuntos
Complexos de Coordenação/química , Substâncias Luminescentes/química , Membranas Artificiais , Potássio/química , Itérbio/química , Cátions/química , Cristalização , Ligantes , Luminescência , Modelos Moleculares , Espectroscopia de Luz Próxima ao Infravermelho
12.
Dalton Trans ; 45(13): 5575-82, 2016 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-26914166

RESUMO

Cobalt-based nanomaterials are promising candidates as efficient, affordable, and sustainable alternative electrocatalysts for the oxygen evolution reaction (OER). However, the catalytic efficiency of traditional nanomaterials is still far below what is expected, because of their low stability in basic solutions and poor active site exposure yield. Here a unique hybrid nanomaterial comprising Co@Co3O4 core-shell nanoparticle (NP) encapsulated N-doped mesoporous carbon cages on reduced graphene oxide (denoted as Co@Co3O4@NMCC/rGO) is successfully synthesized via a carbonization and subsequent oxidation strategy of a graphene oxide (GO)-based metal-organic framework (MOF). Impressively, the special carbon cage structure is very important for not only leading to a large active surface area, enhanced mass/charge transport capability, and easy release of gas bubbles, but also preventing Co@Co3O4 NPs from aggregation and peeling off during prolonged electrochemical reactions. As a result, in alkaline media, the resulting hybrid materials catalyze the OER with a low onset potential of ∼1.50 V (vs. RHE) and an over-potential of only 340 mV to achieve a stable current density of 10 mA cm(-2) for at least 25 h. In addition, metallic Co cores in Co@Co3O4 provide an alternative way for electron transport and accelerate the OER rate.

13.
Inorg Chem ; 53(21): 11498-506, 2014 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-25333867

RESUMO

A novel "turn-on" phosphorescent chemodosimeter based on a cyclometalated Ir(III) complex has been designed and synthesized, which displays high selectivity and sensitivity toward Hg(2+) in aqueous media with a broad pH range of 4-10. Furthermore, by time-resolved photoluminescence techniques, some interferences from the short-lived background fluorescence can be eliminated effectively and the signal-to-noise ratio of the emission detection can be improved distinctly by using the chemodosimeter. Finally, the chemodosimeter can be used to monitor Hg(2+) effectively in living cells by confocal luminescence imaging.


Assuntos
Complexos de Coordenação/química , Irídio/química , Medições Luminescentes , Mercúrio/análise , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/síntese química , Relação Dose-Resposta a Droga , Humanos , Concentração de Íons de Hidrogênio , Estrutura Molecular , Teoria Quântica , Relação Estrutura-Atividade , Fatores de Tempo , Células Tumorais Cultivadas
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