A hybrid nonaqueous electrochemical supercapacitor using nano-sized iron oxyhydroxide and activated carbon

A beta-iron oxyhydroxide (FeOOH) was synthesized via a hydrolyzing route and investigated as a lithium intercalation host. It delivers a capacity of about 170 mAh/g and exhibits good cycling performance when charged/discharged in the voltage range from 1.6 V to 3.3 V. For the first time we have confirmed that FeOOH is suitable for using it as a negative electrode for hybrid electrochemical supercapacitor assembled with an activated carbon positive electrode in 1.0 M LiPF₆ ethylene carbonate/dimethyl carbonate (EC/DMC, 1:2 in volume) solution. The cell reveals a slightly sloping voltage profile from 0 V to 2.8 V and gives an estimated specific energy of 45 Wh/kg based on the total weight of two electrode materials, approximately two times of carbon/carbon electrochemical double layer capacitors. The hybrid supercapacitor shows a good cycling performance, it remains approximately 96% of initial capacity after 800 cycles at a charge/discharge rate of 4 C. The capacitor also shows a desirable rate capability, even at 10 C discharge rate, it holds 80% of capacity compared with that at 1 C discharge rate.     

The Chemical Constituents from the Aerial Part of Rosa laevigata

Eleven chemical constituents were isolated from the ethyl acetate soluble fraction of the aerial part of Rosa laevigata Michx. These compounds include the Henze's ketol (16), diethyl malate (17), three γ-lactones (18-20), loliolide (21), p-coumaric acid (22), 6,7-dimethoxycoumarin (23) and three flavonoids (24-26). The new compounds 19 and 20 were determined to be the cis- and trans-isomers of ethyl 2-benzyl-3-hydroxy-5-oxo-3-furancarboxylate.     

Synthesis,photophysical and electrochemical studies of di-2-pyridyl ketone complexes of rhodium(III)

Complexes of rhodium(III) with di-2-pyridyl ketone (dpk), Rh(dpk)(MeCN)Cl₃ (1) and cis-[Rh(dpk)₂Cl₂]⁺ (2), have been successfully prepared and characterized. At low temperature (77 K), complex (2) in EtOH/MeOH (4:1, v/v) shows a broad, symmetric and structureless red emission with a microsecond lifetime and, hence, is assigned as the dd* phosphorescence. Electrochemical data, including cyclic voltammetry, normal pulse voltammetry, triple pulse voltammetry and controlled potential electrolysis, have been obtained for the two dpk complexes of rhodium(III) in MeCN. On the basis of analysis of the electrochemical (1,2) and luminescence data (2), electron transfer mechanisms are proposed. For complex (1), two reduction processes occur at the metal-localized orbitals with elimination of chlorides during the first reduction step. This is followed by a one-electron reduction at the metal. For complex (2), three electrons are transferred to the metal in two successive reduction steps accompanied by elimination of two chlorides. After these two reduction steps another one-electron reduction occurs at the dpk ligand.     

A theoretical study of electronic excited states of photosynthetic reaction center in Rhodopseudomonas viridis

The electronic singlet vertical excited states of photosynthetic reaction center (PSRC) in Rhodopseudomonas (Rps.) viridis were investigated by ZINDO and INDO/S methods. The effects of the interactions of pigment-pigment and pigment-protein on the electronic excitations were examined. The calculation results showed that the interactions of pigment-pigment and pigment-protein play an important role in reasonably assigning the experimental absorption and circular dichroism (CD) spectra of PSRC in Rps. virids. By comparing the theoretically computed excited states with the experimental absorption and CD spectra, satisfactory assignments of the experimental spectroscopic peaks were achieved.     

酚醛树脂固化过程的红外光谱分析

利用红外光谱(IR)及其变温样品池、定量分析程序对酚醛树脂固化过程中的结构变化进行了研究,它对于酚醛树脂固化过程的质量控制具有重要意义。     

Cobalt-catalyzed regioselective carbocyclization reaction of o-iodophenyl ketones and aldehydes with alkynes, acrylates, and acrylonitrile: a facile route to indenols and indenes

An efficient cobalt-catalyzed carbocylization for the synthesis of indenols and indenes and a new method for reductive decyanation are described. 2-Iodophenyl ketones and aldehydes 1a-g undergo carbocyclization with various disubstituted alkynes 2a-k in the presence of Co(dppe)I(2) and zinc powder in acetonitrile at 80 degrees C for 3 h to afford the corresponding indenol derivatives 3a-s and4a-m in good to excellent yields. For some unsymmetrical alkynes, the carbocyclization was remarkably regioselective, affording a single regioisomer. The cobalt-catalyzed carbocyclization reaction was successfully extended to the synthesis of indene derivatives. Thus, the reaction of 2-iodophenyl ketones and aldehydes (1) with acrylates H(2)C=CHCO(2)R (7a-d) and acrylonitrile H(2)C=CHCN (7e) proceeds smoothly in the presence of Co(dppe)Cl(2)/dppe and zinc powder in acetonitrile at 80 degrees C for 24 h to afford the corresponding indenes 8a-k and 9a-c in moderate to good yields. Interestingly, when 7e was employed for the carbocylization, reductive decyanation also occurred to give an indene derivative without the cyano functionality. A possible mechanism for this cobalt-catalyzed carbocyclization reaction is also proposed.     

Ω型分子筛脱铝的核磁共振研究

在不同投料比（ＳｉＯ２／Ａｌ２Ｏ３＝１３．８，１９及２１）条件下，合成了三种Ω型分子筛原粉．对投料比为１３．８的原粉样品进行了四种不同方式的脱铝处理，即水热、ＳｉＣｌ４、ＥＤＴＡ和（ＮＨ４）２ＳｉＦ６处理，而形成了系列脱铝Ω型分子筛样品．对原粉及其脱铝样品进行了２９Ｓｉ和２７ＡｌＭＡＳＮＭＲ测试，确定出样品骨架硅铝比和铝在两种晶体学不等价Ｔ位上的占据比率，以探索四种脱铝方法的效果．实验结果与分析表明：在所有样品中，铝原子的占据具有择优Ｂ位的倾向；且铝在ＴＡ与ＴＢ位上的占据比率与合成条件有关；四种处理方式对Ω型分子筛的脱铝效果不尽相同．     

Synthesis of phthalide derivatives using nickel-catalyzed cyclization of o-haloesters with aldehydes

The reaction of o-bromobenzoate (1 b) with benzaldehyde (2 a) in the presence of [NiBr(2)(dppe)] (dppe=1,2-bis(diphenylphosphino)ethane) and zinc powder in THF (24 hours, reflux temperature), afforded 3-phenyl-3H-isobenzofuran-1-one (3 a) in an 86 % yield. Similarly, o-iodobenzoate reacts with 2 a to give 3 a, but in a lower yield (50 %). A series of substituted aromatic and aliphatic aldehydes (2 b, 4-MeC(6)H(4)CHO; 2 c, 4-MeOC(6)H(4)CHO; 2 d, 3-MeOC(6)H(4)CHO; 2 e, 2-MeOC(6)H(4)CHO; 2 f, 4-CNC(6)H(4)CHO; 2 g, 4-(Me)(3)CC(6)H(4)CHO; 2 h, 4-C(6)H(5)C(6)H(4)CHO; 2 i, 4-ClC(6)H(4)CHO; 2 j, 4-CF(3)C(6)H(4)CHO; 2 k, CH(3)(CH(2))(5)CHO; 2 l, CH(3)(CH(2))(2)CHO) also underwent cyclization with o-bromobenzoate (1 b) producing the corresponding phthalide derivatives in moderate to excellent yields and with high chemoselectivity. Like 1 b, methyl 2-bromo-4,5-dimethoxybenzoate (1 c) reacts with tolualdehyde (2 b) to give the corresponding substituted phthalide 3 m in a 71 % yield. The methodology can be further applied to the synthesis of six-membered lactones. The reaction of methyl 2-(2-bromophenyl)acetate (1 d) with benzaldehyde under similar reaction conditions afforded six-membered lactone 3 o in a 68 % yield. A possible catalytic mechanism for this cyclization is also proposed.     

Theoretical study of the Diels-Alder reactions between singlet (1Delta g) oxygen and acenes

The G3(MP2) method has been employed to study the 1,4-addition reactions between singlet oxygen and five acenes, including benzene, naphthalene, anthrecene, tetracene, and pentacene. In all, nine pathways between O(2) and the five acenes have been investigated. Our calculated results indicate that all nine pathways are concerted and exothermic and that the most reactive sites on the acenes are the center ring's meso-carbons. In addition, reactivity increases along the series benzene < naphthalene < anthrecene < tetracene < pentacene. This trend is identical to that of aromaticity for the five acenes. A correlation between reactivity and aromaticity is briefly rationalized with natural bond orbital (NBO) analysis and frontier molecular orbital (FMO) analysis. Furthermore, some experimental kinetics data from the literature supporting the calculated results are cited.     

Ternary surface complexes by theE(%)-pH curve method

A new method for the study of ternary surface complexes at liquid-solid interface, theE(%) -pH curve method, was proposed. Four types ofE(%)-pH curves, namely, phenomenon of left-right shifts of S-shaped curve, V-shaped curve, monodirection shift curve and X-shaped curve, were discovered. Correspondingly, apart from type (I) ternary surface complex and type (II) ternary surface complex , a new type of ternary surface complex was discovered. Project supported by the National Natural Science Foundation of China and the Fund of Doctoral Degree’s Spot.