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1.
Chem Commun (Camb) ; 56(14): 2087-2090, 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-31967623

RESUMO

A dual-emissive tris-heteroleptic ruthenium complex is designed, synthesized and applied for the ratiometric photoluminescent detection of amyloid-ß (Aß) aggregation in both steady and transient states. The Aß aggregation is supported by transmission electron microscopy and confocal laser scanning microscopy analysis. In addition, molecular docking calculations have been performed to gain insights into the interaction mode between the ruthenium complex and Aß fibrils.


Assuntos
Peptídeos beta-Amiloides/análise , Complexos de Coordenação/química , Rutênio/química , Complexos de Coordenação/síntese química , Humanos , Simulação de Acoplamento Molecular , Estrutura Molecular , Agregados Proteicos
2.
J Am Chem Soc ; 142(5): 2601-2608, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31939661

RESUMO

Singlet oxygen (1O2), as an important active reagent, has found wide applications in photodynamic therapy (PDT), synthetic chemistry, and materials science. Organic conjugated aromatics serving as hosts to capture and release singlet oxygen have been systematically investigated over the last decades. Herein, we present a [6 + 6] organoplatinum(II) metallacycle by using ∼180° dipyridylanthracene donor and ∼120° Pt(II) acceptor as the building blocks, which enables the capture and release of singlet oxygen with relatively high photooxygenation and thermolysis rate constants. The photooxygenation of the metallacycle to the corresponding endoperoxide was performed by sensitized irradiation, and the resulting endoperoxide is stable at room temperature and can be stored under ambient condition over months. Upon simple heating of the neat endoperoxide under inert atmosphere at 120 °C for 4 h, the resulting endoperoxide can be reconverted to the corresponding parent form and singlet oxygen. The photooxygenation and thermolysis products were characterized by NMR spectroscopy and electrospray ionization time-of-flight mass spectrometric analysis. Density functional theory calculations were conducted in order to reveal the frontier molecular orbital interactions and reactivity. This work provides a new material platform for singlet oxygen related promising applications.

3.
J Am Chem Soc ; 141(50): 19831-19838, 2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31744289

RESUMO

The electrochromic property and device construction of a triphenylamine-based oriented two-dimensional covalent organic framework (2D COF) film on indium tin oxide (ITO) coated glass was reported. The characterization of the 2D COF3PA-TT film revealed that the film was uniform, with good crystallinity, and oriented with its 2D plane parallel to the substrate. For the first time, the electrochromic properties of 2D COF3PA-TT film were studied. 2D COF3PA-TT film on ITO exhibited reversible color transition between deep red and dark brown during redox process. Spectroelectrochemical experiments revealed color changes in the absorption spectra of 2D COF3PA-TT film in the visible and near-infrared regions and showed the characteristics of intervalence charge transfer. The quasi-solid-state electrochromic device was prepared based on the COF3PA-TT film, and it exhibited moderate performance and stability in the near-infrared region.

4.
Chem Commun (Camb) ; 55(89): 13406-13409, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31637391

RESUMO

A new small molecular hole-transporting material, 1,3,6,8-tetrakis[N-(p-methoxyphenyl)-N'-(9,9'-dimethyl-9H-fluoren-2-yl)-amino]pyrene (TFAP) was synthesized and applied in CH3NH3PbI3-perovskite solar cells. A best power conversion efficiency of 19.7% with a photovoltage of 1.11 V has been achieved.

5.
Nat Commun ; 10(1): 4599, 2019 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-31601813

RESUMO

Host-guest interactions are of central importance in many biological and chemical processes. However, the investigation of the formation and decomplexation of host-guest systems at the single-molecule level has been a challenging task. Here we show that the single-molecule conductance of organoplatinum(II) metallocycle hosts can be enhanced by an order of magnitude by the incorporation of a C60 guest molecule. Mechanically stretching the metallocycle-C60 junction with a scanning tunneling microscopy break junction technique causes the release of the C60 guest from the metallocycle, and consequently the conductance switches back to the free-host level. Metallocycle hosts with different shapes and cavity sizes show different degrees of flexibility to accommodate the C60 guest in response to mechanical stretching. DFT calculations provide further insights into the electronic structures and charge transport properties of the molecular junctions based on metallocycles and the metallocycle-C60 complexes.


Assuntos
Fulerenos/química , Compostos Organoplatínicos/química , Teoria da Densidade Funcional , Eletrodos , Ouro , Espectroscopia de Ressonância Magnética , Microscopia de Força Atômica , Microscopia de Tunelamento , Espectrofotometria Ultravioleta
6.
Inorg Chem ; 58(19): 13376-13381, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31532649

RESUMO

In this work, we present the formation of two open-ended hexagonal-prism tubular macrocycles by the [6 + 12] self-assembly of the symmetric ∼120° organic ligand donor with ∼90° Pt(II) acceptor in a 1:2 ratio. The assembled structures were characterized by multinuclear NMR (1H NMR, 31P{1H} NMR, and 1H-1H COSY NMR), electrospray ionization mass spectrometry (ESI-TOF-MS), traveling wave ion mobility-mass spectrometry (TWIM-MS), and transmission electron microscopy. Molecular modeling was further conducted to get insight into their structured characteristics. We also examined their photophysical properties.

7.
Chem Asian J ; 14(18): 3119-3126, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31389657

RESUMO

The bottom-up functionalization of solid surfaces shows increasing importance for a wide range of interdisciplinary applications. Multidentate anchors with more than two contact points can bind to solid surfaces with strong chemisorption, well-defined upright configuration, and tailored functionality. The surface functionalization using multidentate anchors with three (tripodal), four (quadripodal), or more binding points is summarized herein, with a focus on those beyond classical tripodal anchors. In particular, the molecular design on how to achieve multisite interaction between anchor and substrate and the introduction of functional groups to thin films are discussed.

8.
J Am Chem Soc ; 141(15): 6157-6161, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30945852

RESUMO

Polymorphism and anisotropy are fundamental phenomena of crystalline materials. However, the structure-dependent photoluminescent (PL) anisotropy in polymorphic organic crystals has remained unexplored. Herein, two polymorphic nanocrystals, green-emitting nanorods (PtD-g) and yellow-emitting nanoplates (PtD-y), were obtained from a platinum(II)-ß-diketonate complex. The PtD-y crystals display remarkable PL anisotropy with an anisotropy ratio of up to 0.87 whereas the emission of the PtD-g crystals is nearly unpolarized. The polarization properties are rationalized on the different molecular packing of these crystals. By light-harvesting energy transfer, the PtD-y crystals are successfully used to amplify the emission polarization of a red-emitting platinum acceptor (PtA) doped into the donor crystalline matrix, which is otherwise weakly polarized as pure crystals.

9.
Polymers (Basel) ; 11(1)2019 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-30960057

RESUMO

Two star-shaped multi-triphenylamine derivatives 1 and 2 were prepared, where 2 has an additional phenyl unit between a pyrene core and surrounding triphenylamine units. The oxidative electropolymerization of 1 and 2 occurred smoothly to give thin films of polymers P1 and P2. The electrochemistry and spectroelectrochemistry of P1 and P2 were examined, showing two-step absorption spectral changes in the near-infrared region. The electrochromic properties, including contrast ratio, response time, and cyclic stability of P1 and P2 were investigated and compared. Thin film of P2 displays slightly better electrochromic performance than P1, with a contrast ratio of 45% at 1475 nm being achieved.

10.
Langmuir ; 35(20): 6571-6577, 2019 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-31002519

RESUMO

Adequate control over the structures of molecular building blocks plays an important role in the fabrication of desired supramolecular nanostructures at interfaces. In this study, the formation of a pure hydrogen-bonding co-assembly supramolecular nanonetwork on a highly oriented pyrolytic graphite surface was demonstrated by means of a scanning tunneling microscope. The thermal annealing process was conducted to monitor the temperature-triggered structural transformation of the self-assembled nanonetwork. On the basis of the single-molecule-level resolution scanning tunneling microscopy images, together with the density functional theory calculations, the formation mechanisms of the formed nanoarrays were proposed. The results have great significance with regard to controlled construction of complex nanostructures on the surface.

11.
Inorg Chem ; 58(5): 3509-3517, 2019 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-30758195

RESUMO

A cyclometalated ruthenium sensitizer 3 containing a triphenylamine unit was synthesized and immobilized on a nanocrystalline TiO2 surface. By using oxidative electrochemical deposition, a covalent layer of a related cyclometalated ruthenium complex 2 was coupled to the top of dye 3. Electrochemical studies suggested that complex 2 was immobilized on the TiO2/3 film surface by a tetraphenylbenzidine linker to form a dimer-like structure. The immobilization of 3 and 2 was further supported by absorption spectral analysis. The resulting electrodeposited TiO2/(3+2) film displays significantly enhanced sensitizer stabilization toward basic aqueous NaOH solution with respect to the original TiO2/3 film. The dye-sensitized solar cells with the TiO2/(3+2) photoanode display a power conversion efficiency of 4.4%, which is slightly inferior to that with the TiO2/3 film (5.1%) under the same measurement conditions.

12.
Dalton Trans ; 48(6): 2197-2205, 2019 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-30675878

RESUMO

Sb-Doped nanocrystalline SnO2 (SnO2:Sb) thin films functionalized with cyclometalated ruthenium complexes 1 or 2 on FTO conductive glasses have been prepared and characterized. These complexes contain a redox-active amine unit separated from the ruthenium ion by a phenyl or biphenyl linker, respectively, to modify the absorption wavelengths at different redox states. Near-infrared electrochromism of both films has been examined by oxidative spectroelectrochemical measurements and double-potential-step chronoamperometry. A contrast ratio (ΔT%) of 33% at 1070 nm and 63% at 696 nm has been achieved for the SnO2:Sb/1 film in two stepwise oxidation processes, respectively. The other film with complex 2 shows two-step electrochromism at 1310 and 806 nm with ΔT% of 36% and 76%, respectively. The response time of electrochromic switching is around a few seconds. Taking advantage of the good contrast ratio, the rapid response, and the long retention time of each oxidation state, these films have been successfully used to demonstrate surface-confined flip-flop memory functions with a high ON/OFF ratio.

13.
J Org Chem ; 84(4): 2339-2345, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30656930

RESUMO

Acetetracenylene-1,2-dione reacted with 3-ethylrhodanine in the presence of piperidine and Hantzsch ester via a Knoevenagel condensation-reduction sequence to give a tetracene-rhodanine adduct. This reduced Knoevenagel product exhibited magenta luminescence with a fluorescence quantum yield of φ = 0.34 and fluorescence lifetime of τ = 13.2 ns in toluene. Electrochemical studies and charge carrier transport measurements revealed ambipolar properties with hole and electron mobilities of 5.1 × 10-7 and 1.6 × 10-4 cm2/(V s), respectively.

14.
ACS Appl Mater Interfaces ; 10(48): 41592-41598, 2018 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-30406985

RESUMO

By introducing six triarylamine groups to a hexaphenylbenzene (HPB) or a hexakis(2-thienyl)benzene (HTB) core, two propeller-shaped, triarylamine-rich, and low-cost hole-transporting materials (HTMs), which are termed as HPB-OMe and HTB-OMe, respectively, with considerable hole mobility, were obtained by easy synthetic routes. Solid-state planar perovskite CH3NH3PbI3 solar cells (PSCs) with two new HTMs showed high power conversion efficiencies (12.9% for HPB-OMe and 17.3% for HTB-OMe in forward scans) under standard 100 mW cm-2 AM 1.5G illumination without doping. A comparison of matched-degree of energy levels, hole-transporting ability, photovoltaic conversion efficiencies, and recombination of the two HTMs indicated that developing multi-triarylamine- and thiophene-rich molecules provides candidate and efficient dopant-free HTMs for PSCs.

15.
J Am Chem Soc ; 140(39): 12337-12340, 2018 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-30220199

RESUMO

A pyrene-cored molecular quadripod 1,3,6,8-tetra(di( p-pyrid-4-ylphenyl)amino)pyrene (TAPyr) is presented as a noncovalent interfacial coupling reagent for the immobilization of coordination assemblies. This bench-stable molecule is readily available and has a quadripod shape with four pyridine legs and four pyridine handles on the top exterior. By a simple and short dipping procedure under ambient conditions, TAPyr is firmly immobilized on electrode surfaces in an upright fashion as probed by electrochemical, absorption spectral, atomic force microscopy, and scanning tunneling microscopy analysis. Using Pd(PhCN)2Cl2 as a metallolinker, 4-ferrocenylpyridine, a pyridine-terminated monoruthenium complex 1, and a diruthenium complex 2 with two pyridine ends have been grafted onto the ITO/TAPyr surface. The obtained thin films exhibit good electrochemical stability that is comparable or superior to those prepared by the state-of-the-art Si-O-Sn covalent functionalization. Appealing electrochromism is demonstrated with the thin films of ruthenium complexes on ITO.

16.
Angew Chem Int Ed Engl ; 57(34): 10959-10965, 2018 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-29953706

RESUMO

A readily available small molecular hole-transporting material (HTM), OMe-TATPyr, was synthesized and tested in perovskite solar cells (PSCs). OMe-TATPyr is a two-dimensional π-conjugated molecule with a pyrene core and four phenyl-thiophene bridged triarylamine groups. It can be readily synthesized in gram scale with a low lab cost of around US$ 50 g-1 . The incorporation of the phenyl-thiophene units in OMe-TATPyr are beneficial for not only carrier transportation through improved charge delocalization and intermolecular stacking, but also potential trap passivation via Pb-S interaction as supported by depth-profiling XPS, photoluminescence, and electrochemical impedance analysis. As a result, an impressive best power conversion efficiency (PCE) of up to 20.6 % and an average PCE of 20.0 % with good stability has been achieved for mixed-cation PSCs with OMe-TATPyr with an area of 0.09 cm2 . A device with an area of 1.08 cm2 based on OMe-TATPyr demonstrates a PCE of 17.3 %.

17.
J Am Chem Soc ; 140(24): 7723-7729, 2018 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-29782153

RESUMO

The synthesis, characterization, and temperature-responsive properties of two fluorescent organoplatinum(II) metallacycles are reported. Metallacycles M1 and M2 were prepared via the coordination-driven self-assembly of a 120° triarylamine ligand L1 and a 120° diplatinum(II) acceptor Pt-1 or 180° diplatinum(II) acceptor Pt-2, respectively. M1 and M2 are hexagonal metallacycles, comprising of three or six freely rotating anthracene pendants on their periphery, respectively. In response to the temperature variation between -20 and 60 °C, the ligand displays irregular emission changes, whereas both metallacycles show reversible absorption and emission spectral changes in THF. The changes in their green emission intensity also exhibit a linear correlation with the temperature variation, with an average sensitivity of -0.67% and -0.77% per °C for M1 and M2, respectively. Furthermore, in coordinating solvents, such as DMF and CH3CN, M1 and M2 show different behaviors: in the lower temperature range, i.e., below 30 °C, their spectral changes are similar to those observed in THF; however, at a higher temperature the metallacycles were presumably destroyed by the solvents and displayed ratiometric fluorescent responses, including a cyan emission of the ligand L1.


Assuntos
Complexos de Coordenação/química , Corantes Fluorescentes/química , Compostos Organoplatínicos/química , Complexos de Coordenação/síntese química , Fluorescência , Corantes Fluorescentes/síntese química , Ligantes , Modelos Químicos , Estrutura Molecular , Compostos Organoplatínicos/síntese química , Teoria Quântica , Solventes/química , Temperatura Ambiente
18.
Angew Chem Int Ed Engl ; 57(26): 7820-7825, 2018 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-29665184

RESUMO

Thermal-responsive phosphorescent nanotubes have been fabricated from the co-assembly of two neutral iridium complexes, which behave as the antenna chromophores and energy acceptors, respectively, in these highly ordered crystalline superstructures. By tuning the acceptor doping ratio in a range of 0 to 0.5 %, these tubes display color-tunable phosphorescence from green to red at room temperature, and it is attributed to the highly efficient light-harvesting and energy transfer within these materials. For the same reason, the acceptor emission in the nanotubes is amplified more than 800 times with respect to its pure non-emissive solid sample. The doped tubes show reversible thermal-responsiveness, in which the energy transfer was completely suppressed at 77 K and reactivated at room temperature. These processes were characterized by the in situ emission color (green, orange, and red) and spectral changes and lifetime measurements of isolated nanotubes. The temperature-controlled exciton dynamics are responsible for the luminescent thermochromism in these crystalline materials.

19.
J Am Chem Soc ; 140(12): 4269-4278, 2018 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-29522322

RESUMO

Real-time visualization of assembly processes and sophisticated signal processing at the nanoscale are two challenging topics in photonic nanomaterials. Here, high-quality light-harvesting crystalline nanorods were developed by the coassembly of two polypyridyl Ir(III) and Ru(II) metallophosphors, behaving as the antenna chromophore and energy acceptor, respectively. By using a one-pot or stepwise growth condition, homogeneous and multiblock heterojunction nanorods were prepared, respectively. These nanostructures display multicolor phosphorescence from green to red due to the efficient triplet energy transfer and light-harvesting capability at low acceptor doping ratios. Heterojunction nanorods show gradient emission-color switches during different growth stages, in which the real-time stepwise assembly can be vividly visualized using fluorescence microscopy techniques. Triplet excitons were successfully manipulated in both homogeneous and heterojunction nanorods to realize waveguided green, orange, and red emissions and advanced photonic signal logics and encoding/decoding on single multiblock heterojunction nanorod.

20.
Chem Commun (Camb) ; 54(13): 1651-1654, 2018 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-29376171

RESUMO

Two new hole transporting materials (HTMs) based on triphenylamine and carbazole core moieties are designed and applied in planar perovskite solar cells. 18.2% power conversion efficiency (PCE) has been achieved, and 84% of the initial performance can be retained after 50 days.

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