Novel split-band erbium-doped fiber amplifier

In this paper we design a 120 nm bandwidth erbium-doped fiber amplifier using a seed light injection method for the first time. It is shown that when the wavelength of the seed light varies from 1520 to 1570 nm, the gain at 1610 nm reaches maximum near 1553 nm and increases as the seed light power. Based on the method, a novel split-band EDFA configuration is designed. The split-band architecture employs a 1550/1610 nm waveband multiplexer/demultiplexer and two independent sub-bands which pass in parallel through separate branches of the optical amplifier. The signals at independent sub-bands are combined and flattened before output, resulting in a broadband gain-flattened optical amplifier with 120 nm bandwidth.     

Lanthanide coordination polymers and their Ag+-modulated fluorescence

Four 3-D coordination polymers of lanthanide with a tetra(amino acid) ligand, 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetrapropionic acid (H4L, 1), were synthesized. The structure of the Gd(III) complex was characterized. The fluorescence of the Eu(III) complex can be modulated by Ag+.     

A concise total synthesis of (−)-dehydroclausenamide utilizing the novel formation of cis-epoxide as the key step

The asymmetric total synthesis of (−)-dehydroclausenamide 1 was accomplished through a concise and efficient synthetic route employing as the key step the novel formation of cis-epoxy amide 7, which was resulted from the reaction of starting material 4 bearing an optically pure erythro vicinal diol unit with 5H-3-oxa-octafluoro pentanesulfonyl fluoride (HCF₂CF₂OCF₂CF₂SO₂F) in the presence of 1,8-diazabicyclo[5.4.0]-7-undecene (DBU).     

新型植物生长激素油菜甾醇内酯的合成

本文综述了新型植物生长激素油菜甾醇内酯及其类似物的合成,并简要地讨论了它们的结构与生物活性的关系。     

1,10-二氮杂菲-1-氧化物与高氯酸钪、钇的配合物

吡啶类氮氧化物与过渡金属离子能形成稳定的配合物,其中某些配合物具有荧光。在寻找新型发光材料中,这类配合物引起了人们的重视,使这类配合物的合成与性质研究工作得了到广泛的开展。钪、钇与其它吡啶类氨氧化物的配合物已有研究,但与1,10—二氮杂菲—1—氧化物(PhenNO)的配合物至今未见报道,本文研究了钪、钇高氯酸盐与PhenNO配合物的合成及有关性质。     

自制超临界流体萃取仪操作条件的优化及其应用

超临界流体萃取是近年来发展起来的一种新的分离技术。本文使用自己研制的超临界流体萃取仪对吸附有痕量正构烷烃的Ａｌ２Ｏ３进行萃取，对各种操作条件进行优化。并对卢柑皮及生姜样品进行初步的萃取分析。结果证明该仪器设计合理，具有操作简便、高效、自动化程度高的优点，为复杂样品中痕量组分的萃取分析奠定了基础。     

Synthesis,Characterization, and Crystal Structure of Complexes of Lanthanide Picrates with N,N,N′,N′-tetraphenyl-3,6-dioxaoctanediamide

Lanthanide picrate complexes with the ligand N,N,N′,N′-tetraphenyl-3,6-dioxaactanediamide (tdd): [Ln(Pic)₃(tdd)] (Ln = La, Nd, Eu, Tb, Er) have been prepared in a nonaqueous medium and characterized by elemental analysis, conductivity measurements, IR, and ¹H-NMR spectra. The crystal structures of the complexes for Ln = Nd and Er were determined. The early lanthanide, Nd^III, crystallizes as the nona-coordinate complex [Nd(Pic)₃(tdd)]. 2 CH₃CN in the monoclinic space group P2₁n with a = 11.384(2), b = 18.805(4), c = 27.526(5) Å, β = 99.41(1)°, V = 5832(2) ų, and D_c = 1.58 gcm^?3 for Z = 4. The structure was refined to R = 0.0505, based on 4772 observed Deflections. The late lanthanide, Er^III, forms an octa-coordinate complex [Er(Pic)₃(tdd)]; crystals are triclinic, P1, with a = 12.449(2), b = 17.065(2), c = 26.243(4) Å, α = 72.12(1), β = 87.86(1), γ = 84.60(1)°, V = 5282(1) ų, and D_c = 1.68 g cm^?3 for Z, = 4. The structure was refined to R = 0.0469, based on 10666 observed reflections, The results reveal that tdd forms a ring-like structure with its four O-atoms, coordinating to the metal ions as multidentate ligand, together with one O-atom of the bidentate picrate. The structure of the complexes is greatly affected by the ionic radius due to participation of the picrates in coordination.     

Visible and near-infrared luminescence of polycatenated cationic pyridinone lanthanide networks

A series of isomorphic lanthanide coordination polymers [Ln(III)(MBP)_2(NO_3)_2(Br)?2C_3H_6O] [Ln=Eu, Tb, Er, Yb, and Gd; MBP=N,N′-methylene-bis(pyridin-4-one)] featuring polycatenated sql cationic network and incorporated bromide counter ion were prepared. Their visible and near-infrared(NIR) luminescence properties were characterized by steady-state excitation and emission spectra, as well as luminescence lifetimes and quantum yields. The D_(2d) dodecahedron coordination geometry causes visible light excitations and strongly monochromatic emissions. The external heavy-atom environment induces remarkable enhancement on the NIR emissions. The sensitization processes are revealed by analyzing the electronic properties of MBP ligand.     

Pyrazine-linked Iron-coordinated Tetrapyrrole Conjugated Organic Polymer Catalyst with Spatially Proximate Donor-Acceptor Pairs for Oxygen Reduction in Fuel Cells

Nitrogen-coordinated iron (Fe−N₄) materials represent the most promising non-noble electrocatalysts for the cathodic oxygen reduction reaction (ORR) of fuel cells. However, molecular-level structure design of Fe−N₄ electrocatalyst remains a great challenge. In this study, we develop a novel Fe−N₄ conjugated organic polymer (COP) electrocatalyst, which allows for precise design of the Fe−N₄ structure, leading to unprecedented ORR performance. At the molecular level, we have successfully organized spatially proximate iron-pyrrole/pyrazine (FePr/Pz) pairs into fully conjugated polymer networks, which in turn endows FePr sites with firmly covalent-bonded matrix, strong d-π electron coupling and highly dense distribution. The resulting pyrazine-linked iron-coordinated tetrapyrrole (Pz−FeTPr) COP electrocatalyst exhibits superior performance compared to most ORR electrocatalysts, with a half-wave potential of 0.933 V and negligible activity decay after 40,000 cycles. When used as the cathode electrocatalyst in a hydroxide exchange membrane fuel cell, the Pz−FeTPr COP achieves a peak power density of ≈210 mW cm⁻². We anticipate the COP based Fe−N₄ catalyst design could be an effective strategy to develop high-performance catalyst for facilitating the progress of fuel cells.     

MOF‐Derived Hollow CoS Decorated with CeOx Nanoparticles for Boosting Oxygen Evolution Reaction Electrocatalysis

Transition‐metal sulfides (TMSs) have emerged as important candidates for oxygen evolution reaction (OER) electrocatalysts. Now a hybrid nanostructure has been decorated with CeO_x nanoparticles on the surface of ZIF‐67‐derived hollow CoS through in situ generation. Proper control of the amount of CeO_x on the surface of CoS can achieve precise tuning of Co²⁺/Co³⁺ ratio, especially for the induced defects, further boosting the OER activity. Meanwhile, the formation of protective CeO_x thin layer effectively inhibits the corrosion by losing cobalt ion species from the active surface into the solution. It is thus a rare example of a hybrid hetero‐structural electrocatalyst with CeO_x NPs to improve the performance of the hollow TMS nanocage.