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1.
Artigo em Inglês | MEDLINE | ID: mdl-32614983

RESUMO

The coordination of actinides, lanthanides, as well as strontium and cesium with graphdiyne (GDY) was studied by experiments and theoretical calculations. On the basis of experimental results and/or theoretical calculations, it was suggested that Th 4+ , Pu 4+ , Am 3+ , Cm 3+ and Cs + exist in single ion states on the special triangle structure of GDY with various coordination patterns, in which GDY itself is deformed in different manners. Both experiments and theoretical calculations strongly support that UO 2 2+ , La 3+ , Eu 3+ , Tm 3+ and Sr 2+ are not adsorbed by GDY at all. The distinguished adsorption behaviors of GDY afford an important strategy for highly selective separation between actinides and lanthanides, Th 4+ and UO 2 2+ , Cs + and Sr 2+ in nuclear fuel cycle. Also, the present work sheds light on an approach to explore the unique functions and physicochemical properties of actinides in single ion states.

2.
Spectrochim Acta A Mol Biomol Spectrosc ; 219: 401-410, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31059892

RESUMO

Ca3Ga2Ge4O14:Cr3+ phosphors with a broad emission band are prepared by the high temperature solid state method. The emission peak position of Ca3Ga(2-x)Ge4O14:Cr3+ is located at 745 nm. Considering that the biological detection needs a widely spectra matching with the first biological window (650 nm-900 nm), Al3+ and In3+ are introduced into the Ga3+ sites to tune the peak position. When the Ga3+ (0.62 Å) is substituted by smaller Al3+ (0.535 Å), the crystal field around Cr3+ is enhanced, the energy level 4T2(4F) will move up and overlap with 2E(2G) level. As a result, the emission peak of Cr3+shift from 745 nm to 730 nm with an enhancement in the intensity about 19 times due to the electro transfer from 2E(2G) level to 4T2(4F) level. However, the energy level 4T2(4F) will move down when the Ga3+ is replaced by the larger In3+ (0.8 Å), which leads to the red shift of the emission peak from 745 nm to 780 nm. Meanwhile, the intensity is enhanced about 17 times with constructing the defects. In summary, the wide emission spectra of these samples can be tuned from730nm to 780 nm continuously by controlling the concentration of Al3+ and In3+.

3.
Colloid Polym Sci ; 296(11): 1827-1839, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30416246

RESUMO

To explore block glycopolymers as novel polymeric delivery nanocarriers for anticancer drug bortezomib (BTZ), three types of block glycopolymers, poly(ethylene glycol)-block-poly(gluconamido ethyl methacrylate) (PEG113-b-PGAMA20), poly(ethylene glycol)-block-poly(styrene)-block-poly(gluconamido ethyl methacrylate) (PEG113-b-PS50-b-PGAMA20), and poly(ethylene glycol)-block-poly(2-(diethyl amino) ethyl methacrylate)-block-poly(gluconamido ethyl methacrylate) (PEG113-b-PDEA50-b-PGAMA20), were synthesized via atom transfer radical polymerization (ATRP) using a PEG-based ATRP macroinitiator. Three glycopolymers possess the capacity to load BTZ via pH-induced dynamic covalent bonding and/or hydrophobic interaction with their specific self-assembly behaviors, and PEG113-b-PS50-b-PGAMA20 carrier maintains the sustain release behavior of BTZ due to the stable micellar structure; PEG113-b-PDEA50-b-PGAMA20 carrier realizes the abrupt release at pH 5.5 by collapse of micellar structure, while PEG113-b-PGAMA20 carrier exhibits the fastest release at studied solution pHs. This study would provide a light to develop novel block glycopolymer carrier for the delivery of anticancer drug bearing boronic acid groups. Graphical abstractᅟᅟ.

4.
Chemistry ; 24(62): 16558-16569, 2018 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-30168870

RESUMO

The processability and functional performance of stimuli-responsive supramolecular materials are key factors in determining their utility and potential for mass adoption, usage, and profitability. However, it is difficult to predict how structural changes to the molecular components of these systems will impact their operation. Here, a series of π-electron-deficient bis-bipyridinium gemini surfactants were synthesized and evaluated to elucidate the structure-property relationships that govern their ability to form helical-fiber-based donor-acceptor hydrogels, impact hydrogel strength, and influence their solid-state thermochromism. When combined with the π-electron-rich donor melatonin, the helical-fiber- and hydrogel-forming ability of the gemini surfactants was largely influenced by the dimensions of the rigid bridging group that connects the two bis-bipyridinium units. Dynamic viscoelastic rheology and linear sweep voltammetric analysis revealed a positive correlation between the length of the gemini-surfactant bridging group and both the hydrogel strength and the magnitude of the charge-transfer interaction between the donor-acceptor pair. Solid-state thermochromic transition temperatures of processed aerogels, xerogel films, and inkjet-printed patterns were positively correlated with the strength of the charge transfer interaction between the donor-acceptor pair and, thus, also with the length of the gemini surfactant bridging group. The results provide impactful insights that will enable the development of new donor-acceptor-based thermochromes with versatile processability and tunable functionality.

5.
Chemistry ; 24(62): 16553-16557, 2018 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-30089198

RESUMO

Macroscopic enantiomerically pure helical supramolecular fibers are bottom-up assembled in aqueous media from a chiral π-electron donor template and an achiral π-electron acceptor. The helices can be assembled to the sub-millimeter scale with controlled handedness. These dynamic supramolecular architectures allow for a quantitative exchange of the chiral donor template with achiral analogues. During this process, a chiral memory effect was observed, affording enantiomerically pure helices composed entirely of achiral components.

6.
Angew Chem Int Ed Engl ; 56(44): 13727-13731, 2017 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-28887849

RESUMO

Well-defined, fused-ring aromatic oligomers represent promising candidates for the fundamental understanding and application of advanced carbon-rich materials, though bottom-up synthesis and structure-property correlation of these compounds remain challenging. In this work, an efficient synthetic route was employed to construct extended benzo[k]tetraphene-derived oligomers with up to 13 fused rings. The molecular and electronic structures of these compounds were clearly elucidated. Precise correlation of molecular sizes and crystallization dynamics was established, thus demonstrating the pivotal balance between intermolecular interaction and molecular mobility for optimized processing of highly ordered solids of these extended conjugated molecules.

7.
Chem Sci ; 8(4): 2503-2521, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-28553483

RESUMO

Fully conjugated ladder polymers (cLPs), in which all the backbone units on the polymer main-chain are π-conjugated and fused, have attracted great interest owing to their intriguing properties, remarkable chemical and thermal stability, and potential suitability as functional organic materials. The synthesis of cLPs can be, in general, achieved by two main strategies: single-step ladderization and post-polymerization ladderization. Although a variety of synthetic methods have been developed, the chemistry of cLPs must contend with structural defects and low solubility that prevents complete control over synthesis and structural characterization. Despite these challenges, cLPs have been used for a wide range of applications such as organic light emitting diodes (OLEDs) and organic field effect transistors (OFETs), paralleling developments in processing methods. In this perspective, we discuss the background of historical syntheses including the most recent synthetic approaches, challenges related to the synthesis and structural characterization of well-defined cLPs with minimum levels of structural defects, cLPs' unique properties, and wide range of applications. In addition, we propose outlooks to overcome the challenges limiting the synthesis, analysis, and processing of cLPs in order to fully unlock the potential of this intriguing class of organic materials.

8.
Phys Rev E ; 95(1-1): 012315, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28208319

RESUMO

The dynamical tolerance of coupled oscillator networks against local failures is studied. As the fraction of failed oscillator nodes gradually increases, the mean oscillation amplitude in the entire network decreases and then suddenly vanishes at a critical fraction as a phase transition. This critical fraction, widely used as a measure of the network robustness, was analytically derived for random failures but not for targeted attacks so far. Here we derive the general formula for the critical fraction, which can be applied to both random failures and targeted attacks. We consider the effects of targeting oscillator nodes based on their degrees. First we deal with coupled identical oscillators with homogeneous edge weights. Then our theory is applied to networks with heterogeneous edge weights and to those with nonidentical oscillators. The analytical results are validated by numerical experiments. Our results reveal the key factors governing the robustness and fragility of oscillator networks.

9.
Chaos ; 27(12): 123105, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29289041

RESUMO

Robustness of coupled oscillator networks against local degradation of oscillators has been intensively studied in this decade. The oscillation behavior on the whole network is typically reduced with an increase in the fraction of degraded (inactive) oscillators. The critical fraction of inactive oscillators, at which a transition from an oscillatory to a quiescent state occurs, has been used as a measure for the network robustness. The larger (smaller) this measure is, the more robust (fragile) the oscillatory behavior on the network is. Most previous studies have used oscillators with identical natural frequencies, for which the oscillators are necessarily synchronized and thereby the analysis is simple. In contrast, we focus on the effect of heterogeneity in the natural frequencies on the network robustness. First, we analytically derive the robustness measure for the coupled oscillator models with heterogeneous natural frequencies under some conditions. Then, we show that increasing the heterogeneity in natural frequencies makes the network fragile. Moreover, we discuss the optimal parameter condition to maximize the network robustness.

10.
Org Lett ; 18(24): 6332-6335, 2016 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-27978664

RESUMO

Active conformational control is realized in a conjugated system using intramolecular hydrogen bonds to achieve tailored molecular, supramolecular, and solid-state properties. The hydrogen bonding functionalities are fused to the backbone and precisely preorganized to enforce a fully coplanar conformation of the π-system, leading to short π-π stacking distances, controllable molecular self-assembly, and solid-state growth of one-dimensional nano-/microfibers. This investigation demonstrates the efficiency and significance of an intramolecular noncovalent approach in promoting conformational control and self-assembly of organic molecules.

11.
Chem Sci ; 7(2): 881-889, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-28791119

RESUMO

The synthesis of a carbazole-derived, well-defined ladder polymer was achieved under thermodynamic control by employing reversible ring-closing olefin metathesis. This unique approach featured mild conditions and excellent efficiency, affording the ladder polymer backbone with minimum levels of unreacted defects. Rigorous NMR analysis on a 13C isotope-enriched product revealed that the main-chain contained less than 1% of unreacted precursory vinyl groups. The rigid conformation of the ladder-type backbone was confirmed by photophysical analysis, while the extended rod-like structure was visualized under scanning tunneling microscope. Excellent solubility of this polymer in common organic solvents allowed for feasible processing of thin films using solution-casting techniques. Atomic force microscopy and grazing incident X-ray scattering revealed a uniform and amorphous morphology of these films, in sharp contrast to the polycrystalline thin films of its small molecular counterpart.

12.
Chem Commun (Camb) ; 52(14): 2928-31, 2016 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-26688107

RESUMO

Selective desorption of (6,5) single-wall carbon nanotubes from hydrogels only occurs at specific co-surfactant ratios. High-purity fractions are obtained at this ratio even with long elution times and different total co-surfactant concentrations. These results suggest that each (n,m) type forms a thermodynamically-stable surfactant structure in the co-surfactant solution, enabling high-fidelity separations in a single column.


Assuntos
Hidrogéis , Nanotubos de Carbono , Tensoativos/química
13.
Org Lett ; 17(12): 3146-9, 2015 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-26068667

RESUMO

A highly efficient and feasible "condensation followed by annulation" synthetic approach was developed to afford a subset of 9-ring-fused quinacridone derivatives on a 10 g scale. Despite the amenable intermolecular hydrogen-bonding ability of these rigid molecules, good solubility in common organic solvents and solution processability into uniformed thin films were achieved. Integrated advantages in the synthesis and properties make these compounds ideal building blocks for high-performance dyes and optoelectronic materials.

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