氧化条件下NOx催化的甲烷均相部分氧化

考察了没有固体催化剂时NOx对甲烷气相氧化的促进作用.实验结果表明，即使在强氧化条件下（O2/CH4=5），NOx对甲烷部分氧化制一氧化碳仍然有明显的催化活性.在CH4-O2体系中加入0.005％～0.2％的NO后，反应温度可降低200-300 ℃.在反应产物中还可观察到甲醛和乙烯，通过改变反应条件可以控制它们的相对浓度.     

氧化物担载Ni（C5H5）2衍生催化剂的EXAFS表征

本文以二茂镍为母体化合物,以氧化铝和氧化硅为担体制备了担载镍催化剂。为了表征其结构特点,对这些催化剂热分解处理前后的样品在日本筑波高能物理研究所(Photon-Factory)的同步辐射加速器BL—10B EXAFS实验站进行了外延x-光精细结构谱测定(透射法)。以单散射球面波理论对实验结果进行了多参数拟合,同时对母体化合物也进行了平行测定和拟合,以验证数据及拟合方法的可靠性。研究结果表明,母体化合物的EXAFS结果与文献XRD相一致;母体化合物与担体表面发生了强烈的化学作用;镍组分在催化剂表面高度分散,氧化铝与Ni(C_5H_5)_2有更强的相互作用形成。Ni[(O)_s]_n(n≈4),近一半的镍原子周围有0.30 nm处的镍原子散射;氧化硅上除Ni[(CO)_s]_n(n≈3)外,在0.30 nm处有配位数为2的非成键Ni原子。     

Fe(bpb)(CN)2]- as a versatile building block for the design of novel low-dimensional heterobimetallic systems: synthesis, crystal structures, and magnetic properties of cyano-bridged Fe(III)-Ni(II) complexes [(bpb)(2-) = 1,2-bis(pyridine-2-carboxamido)benzenate

A dicyano-containing [Fe(bpb)(CN)2]- building block has been employed for the synthesis of cyano-bridged heterometallic Ni(II)-Fe(III) complexes. The presence of steric bpb(2-) ligand around the iron ion results in the formation of low-dimensional species: five are neutral NiFe2 trimers and three are one-dimensional (1D). The structure of the 1D complexes consists of alternating [NiL]2+ and [Fe(bpb)(CN)2]- generating a cyano-bridged cationic polymeric chain and the perchlorate as the counteranion. In all complexes, the coordination geometry of the nickel ions is approximately octahedral with the cyano nitrogen atoms at the trans positions. Magnetic studies of seven complexes show the presence of ferromagnetic interaction between the metal ions through the cyano bridges. Variable temperature magnetic susceptibility investigations of the trimeric complexes yield the following J(NiFe) values (based on the spin exchange Hamiltonian H = -2J(NiFe) S(Ni) (S(Fe(1)) + S(Fe(2))): J(NiFe) = 6.40(5), 7.8(1), 8.9(2), and 6.03(4) cm(-1), respectively. The study of the magneto-structural correlation reveals that the cyanide-bridging bond angle is related to the strength of magnetic exchange coupling: the larger the Ni-N[triple bond]C bond angle, the stronger the Ni- - -Fe magnetic interaction. One 1D complex exhibits long-range antiferromagnetic ordering with T(N) = 3.5 K. Below T(N) (1.82 K), a metamagnetic behavior was observed with the critical field of approximately 6 kOe. The present research shows that the [Fe(bpb)(CN)2]- building block is a good candidate for the construction of low-dimensional magnetic materials.     

Heterotrimetallic 4f-3d coordination polymers: synthesis, crystal structure, and magnetic properties

A series of cyano-bridged heterotrimetallic complexes [CuL](2)Ln(H(2)O)(2)M(CN)(6).7H(2)O have been synthesized by the reactions of CuL (L(2)(-) = dianion of 1,4,8,11-tetraazacyclotradecane-2,3-dione), Ln(3+) (Ln = Gd or La), and [M(CN)(6)](3)(-) (M = Co, Fe, or Cr). X-ray diffraction analysis reveals that these complexes are isostructural and have a novel chain structure. The Ln(3+) ion is eight-coordinated by six oxygen atoms of two CuL and two water molecules and two nitrogen atoms of the bridging cyano ligands of two [M(CN)(6)](3)(-), while the [M(CN)(6)](3)(-) anion connects two Ln(3+) using two trans-CN(-) ligands giving rise to a chainlike structure. In the chain, every CuL group tilts toward the CN(-) ligand of adjacent [M(CN)(6)](3)(-) with the Cu-N(cyano) contacts ranging from 2.864(6) to 2.930(6) A. Magnetic studies on the CuGdCo complex (1) indicate the presence of ferromagnetic coupling between Cu(II) and Gd(III). The CuLaCr (5) and CuLaFe (2) complexes exhibit ferromagnetic interaction between paramagnetic Cu(II) and Cr(III)/Fe(III) ions through the weak cyano bridges (Cu-N(cyano) = 2.930(6) A for 2). A global ferromagnetic interaction is operative in the CuGdFe complex (3) with the concurrence of dominant ferromagnetic Cu(II)-Gd(III) and minor antiferromagnetic Gd(III)-Fe(III) as well as the ferromagnetic Cu(II)-Fe(III) interaction. For the CuGdCr complex (4), an overall antiferromagnetic behavior was observed, which is attributed to the presence of dominant antiferromagnetic Cr(III)-Gd(III) coupling and the minor ferromagnetic Cu(II)-Gd(III) and Cu(II)-Cr(III) interaction. Moreover, a spin frustration phenomenon was found in complex 4, which results from the ferro-ferro-antiferromagnetic exchanges in the trigonal Cu-Gd-Cr units. The magnetic susceptibilities of these complexes were simulated using suitable models. The magneto-structural correlation was investigated. These complexes did not show a magnetic phase transition down to 1.8 K.     

The efficient in‐situ reduction and cyclization reaction of aromatic aldehyde, 1,3‐cyclopentanedione (tetronic acid), and nitro‐compound under SnCl2·2H2O‐THF medium

An efficient in‐situ reduction and cyclization reaction for the synthesis of pyrazolo[4,3‐f]quinoline, pyrazolo[3,4‐f]quinoline, and pyrazolo[3,2‐f]quinoline derivatives directly form 5‐nitroindazole, 6‐nitroindazole and 5‐nitroindole in the presence of SnCl₂·2H₂O was reported. Compared to traditional synthetic methods, this approach has the advantages of stable reagents, easy obtaining raw material, and high yields. In this research, SnCl₂·2H₂O is the efficient reducing agent for the in‐situ reduction and cyclization reaction of nitro‐compound. In addition, this process provided an alternative approach for the synthesis of target compounds.     

Study of three rotating radio transients with FAST

Rotating radio transients(RRATs) are peculiar astronomical objects whose emission mechanism remains under investigation.In this paper, we present observations of three RRATs, J1538+2345, J1854+0306 and J1913+1330, carried out with the Fivehundred-meter Aperture Spherical radio Telescope(FAST). Specifically, we analyze the mean pulse profiles and temporal flux density evolutions of the RRATs. Owing to the high sensitivity of FAST, the derived burst rates of the three RRATs are higher than those in previous reports. RRAT J1854+0306 exhibited a time-dynamic mean pulse profile, whereas RRAT J1913+1330 showed distinct radiation and nulling segments on its pulse intensity trains. The mean pulse profile variation with frequency is also studied for RRAT J1538+2345 and RRAT J1913+1330, and the profiles at different frequencies could be well fitted with a cone-core model and a conal-beam model, respectively.     

Synthesis,structural characterization and catalytic activity of benzimidazole‐functionalized Pd(II) N‐heterocyclic carbene complexes

Two Pd(II)–NHC complexes bearing benzimidazole and pyridine groups have been successfully prepared and fully characterized by NMR and X‐ray diffraction analysis. The structure of palladium complexes are a typical square‐planar with palladium surrounded by two pairs of trans‐arranged benzimidazole and carbene ligands. The Pd–NHC complexes have been proved to be a highly efficient catalyst for the Mizoroki–Heck coupling reaction of aryl halides with various substituted acrylates under mild conditions in excellent yields. Copyright © 2013 John Wiley & Sons, Ltd.     

Estimation,dependence and stability of solutions of an iterative equation

Aequationes mathematicae - In this paper we study estimation, continuous dependence and Hyers–Ulam stability for continuous solutions of a second order iterative equation. First we give an...     

Synthesis and surfactochromicity of 1,4‐diketopyrrolo[3,4‐c]pyrrole(DPP)‐based anionic conjugated polyelectrolytes

Two novel anionic conjugated copolyelectrolytes PSDPPPV and PSDPPPE were synthesized via Heck/Sonogashira coupling reactions and characterized by FT‐IR, ¹H NMR, UV‐vis, and PL spectroscopy. The two polymers are respectively constituted of 2,5‐diethoxy‐1,4‐phenyleneethynylene (DPV) and 2,5‐diethoxy‐1,4‐phenyleneethynylene (DPE) with 1,4‐diketo‐2,5‐bis(4‐sulfonylbutyl)‐3,6‐diphenylpyrrolo[3,4‐c]pyrrole (SDPP) which is a novel water soluble diketopyrrolopyrrole derivative. PSDPPPV and PSDPPPE show broad absorption band in visible region and they exhibit strong fluorescence quenching in aqueous solution. The fluorescence of their aqueous solutions can be enhanced in the presence of cationic surfactant or polymer nonionic surfactant. Fluorescence enhancement by introduction of polyvinylpyrrolidone (PVP) shows linear response. This result provides a controllable method to increase fluorescence intensity of dipyrrolopyrrole‐based conjugate polyelectrolytes in aqueous phase. The optical properties suggested that PSDPPPV and PSDPPPE which are negatively charged conjugated polymers can assemble with positively charged photovoltaic materials to form ionic photoactive layer. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 739–751