Institute of Chemistry
Changchun Institute of Applied Chemistry, Chinese Academy Of SciencesNot a member yet
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Synthesis, characterization and 1,3-butadiene polymerization studies of cobalt dichloride complexes bearing pyridine bisoxazoline ligands
Get PDFseries of ion-pair cobalt contlexes bearing pyridine bisoxazoline ligands were successfully synthesized and characterized by IR spectroscopy and elemental analysis. Determined by X-ray crystallographic analysis, complexes 4a, 4b, 4e, and 4f existed as ion pairs comprised of [CoL2](2+) and [CoCl4](2-). In the complex, the cobalt atom was coordinated by six nitrogen atoms from two ligands, and its coordination geometry at the cobalt center of [CoL2](2+) can be described as distorted octahedron. In combination with ethylaluminum sesquichloride, these cobalt complexes displayed high catalytic activity and cis-1,4-selectivity towards 1,3-butadiene polymerization. The selectivity of the catalytic system can be tuned to predominantly 1,2-fashion via addition of PPh3. The effects of reaction parameters and the ligand environment on the polymerization were also investigated. (C) 2015 Elsevier Ltd. All rights reserved
Biochemical oxygen demand measurement by mediator method in flow system
No full textUsing mediator as electron acceptor for biochemical oxygen demand (BOD) measurement was developed in the last decade (BODMed). However, until now, no BODMed in a flow system has been reported. This work for the first time describes a flow system of BODMed method (BODMed-FS) by using potassium ferricyanide as mediator and carbon fiber felt as substrate material for microbial immobilization. The system can determine the BOD value within 30 min and,possesses a wider analytical linear range for measuring glucose-glutamic acid (GGA) standard solution from 2 up to 200 mg L-1 without the need of dilution. The analytical performance of the BODMed-FS is comparable or better than that of the previously reported BODMed method, especially its superior long-term stability up to 2 months under continuous operation. Moreover, the BODMed-FS has same determination accuracy with the conventional BOD5 method by measuring real samples from a local wastewater treatment plant (WWTP). (C) 2015 Elsevier B.V. All rights reserved
Mitochondria-Localized Fluorescent BODIPY-Platinum Conjugate
No full textA convenient synthesis of a BODIPY (1,3,5,7-tetramethyl-8-(4-pyridyl)-4,4'-difluoroboradiazaindacene) labeled platinum compound (BODIPY-Pt) was developed by direct conjugation of cisplatin with the pyridine group of BODIPY. The membrane permeability and selective uptake of BODIPY-Pt in the mitochondria was studied using confocal laser scanning microscopy (CLSM). The fluorescent BODIPY-Pt conjugate showed high cellular proliferation inhibition against human cervical carcinoma (HeLa) and human breast cancer (MCF-7) cells, with half maximal inhibitory concentrations (IC50) of 27.37 and 12.14 mu M, respectively. This work highlights the potential of using BODIPY labeled Pt compounds to realize the visualization of Pt distribution in living cells
High performance and reversible ionic polypeptide hydrogel based on charge-driven assembly for biomedical applications
No full textIn the pursuit of new strategies for the design and synthesis of high performance, physically associated hydrogels, dynamic materials formed through electrostatic interactions can serve as a powerful model. Here, we introduce a convenient strategy to obtain biodegradable hydrogels from ABA triblock ionic polypeptides formed by mixing poly(L-glutamic acid)-block-poly(ethylene glycol)-block-poly(L-glutamic acid) (PGA-PEG-PGA) with poly(L-lysine)-block-poly(ethylene glycol)-block-poly(L-lysine) (PLL-PEG-PLL). The hydrogels showed tunable physical properties, high strength and reversible response. The reactive function groups in the ionic blocks can conjugate with oppositely charged drugs or proteins and allow for further modification. These ionic ABA triblock polyelectrolytes can also encapsulate intact cells without significantly compromising cell viability, suggesting that the hydrogels have excellent cytocompatibility. In vivo evaluation performed in rats with subcutaneous injection indicated that the gels were formed and degraded, and hematoxylin and eosin staining suggested good biocompatibility in vivo. In addition, these advantages, combined with the synthetic accessibility of the copolymer, make this cross-linking system a flexible and powerful new tool for the development of injectable hydrogels for biomedical applications. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved
Graphene Nanoribbon-Supported PtPd Concave Nanocubes for Electrochemical Detection of TNT with High Sensitivity and Selectivity
No full textIn this work, PtPd concave nanocubes anchored on graphene nanoribbons (PtPd-rGONRs) were successfully fabricated through a hydrothermal process. The structural characterizations confirmed that PtPd concave cubes with an average size of around 11 nm have been successfully synthesized and they are uniformly assembled on the surface of rGONRs. The electrochemical measurements demonstrated that the PtPd-rGONRs composite-modified glassy carbon electrode (GCE) shows much enhanced current signals for TNT reduction, which is 4 and 12-fold higher than rGONRs and bare glassy carbon electrode, respectively. The PtPd-rGONRs exhibited a wide linear range for TNT detection from 0.01 to 3 ppm with the sensing limit of 0.8 ppb. Moreover, the PtPd-rGONRs showed excellent detection stability for the determination of TNT. Most importantly, the PtPd-rGONRs-based electrochemical detection platform can be successfully applied to TNT detection in tap water and real lake water samples. The present study indicates that graphene nanoribbon-supported nanocrystals are promising in designing high performance electrochemical sensors for explosives detection
Direct Electrochemistry of Glucose Oxidase on Novel Free-Standing Nitrogen-Doped Carbon Nanospheres@Carbon Nanofibers Composite Film
No full textWe have proposed a novel free-standing nitrogen-doped carbon nanospheres@carbon nanofibers (NCNSs@CNFs) composite film with high processability for the investigation of the direct electron transfer (DET) of glucose oxidase (GOx) and the DET-based glucose biosensing. The composites were simply prepared by controlled thermal treatment of electrospun polypyrrole nanospheres doped polyacrylonitrile nanofibers (PPyNSs@PAN NFs). Without any pretreatment, the as-prepared material can directly serve as a platform for GOx immobilization. The cyclic voltammetry of immobilized GOx showed a pair of well-defined redox peaks in O-2-free solution, indicating the DET of GOx. With the addition of glucose, the anodic peak current increased, while the cathodic peak current decreased, which demonstrated the DET-based bioelectrocatalysis. The detection of glucose based on the DET of GOx was achieved, which displayed high sensitivity, stability and selectivity, with a low detection limit of 2 mu M and wide linear range of 12-1000 mu M. These results demonstrate that the as-obtained NCNSs@CNFs can serve as an ideal platform for the construction of the thirdgeneration glucose biosensor
Multimodal cancer imaging using lanthanide-based upconversion nanoparticles
No full textMultimodal nanoprobes that integrate different imaging modalities in one nano-system could offer synergistic effect over any modality alone to satisfy the higher requirements on the efficiency and accuracy for clinical diagnosis and medical research. Upconversion nanoparticles (UCNPs), particularly lanthanide (Ln)-based NPs have been regarded as an ideal building block for constructing multimodal bioprobes due to their fascinating properties. In this review, we first summarize recent advances in the optimizations of existing UCNPs. In particular, we highlight the applications of Ln-based UCNPs for multimodal cancer imaging in vitro and in vivo. The explorations of UCNPs-based multimodal nanoprobes for targeting diagnosis and imaging-guided therapeutics are also presented. Finally, the challenges and perspectives of Ln-based UCNPs in this rapid growing field are discussed
Anions Influence the Relaxation Dynamics of Mono-mu(3)-OH-Capped Triangular Dysprosium Aggregates
No full textA family of four Dy-3 triangular circular helicates, namely, [Dy-3(HL)(3)(mu(3)-OH)(CH3OH)(2)(H2O)(4)]Cl-1.5(OH)(0.5).0.5H(2)O (1), [Dy-3(HL)(3)(mu(3)-OH)(CH3OH)(3)(H2O)(2)Cl]Cl.CH3OH (2), [Dy-3(HL)(3)(mu(3)-OH)(CH3OH)(3)(H2O)(2)(NO3)](NO3) (3), and [Dy-3(HL)(3)(mu(3)-OH)(CH3OH)(4)(ClO4)](ClO4) (4), were assembled by the reaction of a new acylhydrazone ligand H3L [(3-hydroxy)-N'-((8-hydroxyquinolin-2-yl)methylene)picolinohydrazide] with different dysprosium(III) salts. These compounds represent the first examples of mu-Oacylhydrazone-bridged triangular Dy3 SMMs reported to date. Alternating-current magnetic susceptibility measurements revealed that compounds 1 and 2 show typical SMM behavior with the occurrence of multiple relaxation processes, whereas frequency-dependent relaxation signals without chi peaks were observed in 3 and 4 under zero dc field. Such distinct dynamic behaviors are attributed to the different sizes of the terminal coordination solvent/anions (H2O, Cl, NO3, and ClO4 for 1-4, respectively) at the Dy-3 site. Here, similar deviations from the ideal monocapped square-antiprismatic (C-4v) geometry defined by SHAPE software were observed around local Dy centers in 1 and 2, whereas the situation was completely different in 3 and 4 as a result of the presence of relatively large anions in the limited space defined by three intercrossing rigid hydrazone ligands
Balancing the H- and J-aggregation in DTS(PTTh2)(2)/PC70BM to yield a high photovoltaic efficiency
Get PDFThe content and ratio of two stacking styles, namely H-aggregation and J-aggregation, of 5,5'-bis{(4-(7-hexylthiophen-2-yl)thiophen-2-yl)-[1,2,5]thiadiazolo[3,4-c]pyridine}-3,3'-di-2-ethylhexylsilylene-2,2'-bithiophene, DTS(PTTh2)(2), had a profound influence on the performance of solar cells based on DTS(PTTh2)(2)/[6,6]phenyl-C71-butyric acid methyl ester (PC70BM) (7/3, w/w) blend films. It was found that the H/J ratio could be tuned from 0.30 to 1.40 by controlling the boiling point of the main solvent, the content of additives and the selective dissolution by additives (such as 1,8-diiodooctane (DIO), 1,6-diiodohexane (DIH) and 1,4-diiodobutane (DIB)) of the DTS(PTTh2)(2) side chains. The power conversion efficiency (PCE) of DTS(PTTh2)(2)/PC70BM was firstly improved, then decreased with increasing H/J ratio. The best PCE of 6.51% was achieved by adding 0.20 vol% 1,6-diiodohexane (DIO) into solutions in thiophene (Th), which improved it by 203% compared to the reference without additives, when the H/J ratio was 1.01. Balance between the two stacking styles is needed for the device to obtain best performance. On one hand, J-aggregation was favorable for forming more excitons because a lower energy was needed to excite the J-aggregation. On the other hand, the H-aggregation favored exciton dissociation for two reasons: providing excitons with a longer lifetime and stronger driving force for exciton dissociation. In addition, the complementary light absorption of the two stacking styles is advantageous for maximal light absorption
Polyphenylene Wrapped Sulfur/Multi-Walled Carbon Nano-Tubes via Spontaneous Grafting of Diazonium Salt for Improved Electrochemical Performance of Lithium-Sulfur Battery
No full textA novel conducting polymer polyphenylene is used to in situ wrap the MWCNT-core/Sulfur-shell composite via the spontaneous polymerization reaction process of benzenediazonium tetrafluoroborate (ArN2+ BF4-). The porous conductive polymer skin layer effectively prevents the dissolution of active sulfur and facilitates the diffusion of lithium ion towards to reaction site, due to the shortened diffusion distance. Moreover, this resulting architecture structure, Polyphenylene/S/MWCNTs, can accommodate the large volumetric expansion of sulfur during lithiation procedure, improving the cycling stability and rate capability of lithium-sulfur batteries. It delivers an initial discharge capacity of 1491.3 mAh/g at 0.1 C, and the remaining capacity is 1015.6 mAh/g after 75 cycles. The as-prepared material also exhibits an excellent rate capability and cyclability at 0.5 C, 1 C and 5 C. Our experimental results manifest that this composite is a potential candidate as cathode material for high performance lithium-sulfur batteries in the future. (C) 2015 Elsevier Ltd. All rights reserved