反胶束法制备直接甲醇燃料电池Pt-Sn/C催化剂及其表征

在水/AOT/环己烷反胶束体系中, 制备了Pt-Sn/C催化剂, 研究了不同ω (反胶束溶液中水与表面活性剂的物质量之比)值对Pt-Sn粒径的影响. 并采用TEM, XRD, XPS, 循环伏安等技术对其进行表征. TEM结果表明合成的Pt-Sn纳米颗粒为球形, 在碳载体表面均匀分布, 粒径分布窄, 平均粒径为2.7 nm. Pt-Sn颗粒尺寸随着ω的增加而增大. XRD结果表明该催化剂中Pt具有面心立方结构且没有与Sn形成合金. XPS结果表明在该催化剂中, Pt主要以零价态存在. 在甲醇溶液中的循环伏安扫描结果表明, 甲醇氧化峰电位和峰电流随着ω的增加而减小, 说明反胶束方法可以通过控制颗粒尺寸, 从而影响催化剂的电氧化活性. 相对于商用Pt-Ru/Vulcan XC-72 (20 wt%, E-TEK公司), 该催化剂具有较低的峰电势以及较高的I_f/I_b (循环伏安曲线中正向扫描峰电流与反向扫描峰电流的比值), 这表明用此方法制备的Pt-Sn/C催化剂具有较好的抗中毒能力.     

Studies of AuNi alloys by electron spectroscopies with the aid of the line shape analysis by the pattern recognition method

The spectrum of electrons elastically backscattered from the surface and within its vicinity reflects the probability of electron elastic backscattering on the surface atoms, quasi‐elastic scattering and the inelastic scattering visible in the low energy side of the elastic peak. The method for investigating the processes of electron elastic backscattering on the surface atom is called the elastic peak electron spectroscopy (EPES). In the present work, AuNi alloys of different compositions are investigated using X‐ray photoelectron spectroscopy (XPS) and the EPES method with the aid of the line shape analysis called the fuzzy k‐nearest neighbour (fkNN) rule. The line shape analysis was found to be applicable for EPES spectroscopy. It allows distinguishing the surfaces exhibiting various surface roughness, texture and grain size, and quantifying the selected information depths. The quantitative results obtained from the XPS analysis and the EPES spectra line shape analysis indicated Au surface segregation with Au surface enriched profile. Quantitative discrepancies are discussed within the non‐uniform concentration profiles of constituents due to sputter cleaning and annealing, different diffusion coefficients for Au and Ni, differences in the information depths sampled by XPS and EPES methods and differences in electron elastic backscattering cross‐sections for Ni and Au. Copyright © 2006 John Wiley & Sons, Ltd.     

Kristallstrukturen,Normalkoordinatenanalysen und 15N‐NMRund 77Se‐NMR‐Verschiebungen von trans‐[OsO2(NCO)4]2–, trans‐[OsO2(NCS)4]2– und trans‐[OsO2(SeCN)4]2–

Crystal Structures, Normal Coordinate Analyses, and ¹⁵N NMR and ⁷⁷Se NMR Chemical Shifts of trans ‐[OsO₂(NCO)₄]^2–, trans ‐[OsO₂(NCS)₄]^2–, and trans ‐[OsO₂(SeCN)₄]^2– The crystal structures of trans‐(Ph₃PNPPh₃)₂[OsO₂(NCO)₄] ( 1 ) (orthorhombic, space group Pbca, a = 19.278(3), b = 16.674(4), c = 19.982(2) Å, Z = 4), trans(n‐Bu₄N)₂[OsO₂(NCS)₄] ( 2 ) (triclinic, space group P1, a = 12.728(3), b = 12.953(3), c = 16.255(6) Å, α = 97.39(4), β = 105.62(2), γ = 95.25(3)°, Z = 2) and trans‐(n‐Bu₄N)₂[OsO₂(SeCN)₄] ( 3 ) (tetragonal, space group I4/m, a = 13.406(2), c = 12.871(1) Å, Z = 2) have been determined by single‐crystal X‐ray diffraction analysis, showing the bonding of NCO and NCS via the N atom but the coordination of SeCN via the Se atom to osmium. Based on the molecular parameters of the X‐ray determinations the vibrational spectra have been assigned by normal coordinate analyses. The valence force constants are for 1 f_d(OsO) = 6.43, f_d(OsN) = 3.32, f_d(NC) = 14.50, f_d(CO) = 12.80, for 2 f_d(OsO) = 6.56, f_d(OsN) = 1.75, f_d(NC) = 15.00, f_d(CS) = 5.50, and for 3 f_d(OsO) = 6.75, f_d(OsSe) = 0.99, f_d(SeC) = 3.23, f_d(CN) = 15.95 mdyn/Å. The observed NMR shifts are δ(¹⁵N) = –386.6 ( 1 ), δ(¹⁵N) = –294.7 ( 2 ) and δ(⁷⁷Se) = 108.8 ppm ( 3 ).     

Grafting of aldehyde structures to single‐walled carbon nanotubes for application in phenolic resin‐based composites

Grafting of aldehyde structures to single‐walled carbon nanotubes (SWNTs) has been carried out to endow the nanotubes with appropriate wettability. The results of Fourier transform infrared (FTIR) spectroscopy, ultraviolin‐visible‐near infrared (UV‐VIS‐NIR) spectroscopy, and Raman spectroscopy provide the supporting evidence of aldehyde structures covalently attached to SWNTs. The improved wettability of aldehyde‐functionalized SWNTs (f‐SWNTs) was demonstrated by their good dispersion in organic medium, namely, ethanol and phenolic resin. The prospective covalent bonding between aldehyde structures on the surfaces of f‐SWNTs and phenolic resin makes it possible to prepare an integrated composite with the enhanced‐interfacial adhesion. The f‐SWNT composites, therefore, show much higher average values of dσ/dW_CNT and dE/dW_CNT (i.e., tensile strength and Young's modulus per unit weight fraction) compared with the composites filled with pristine SWNTs or MWNTs. The respective maxima are 9680 MPa and 320 GPa. It is thus feasible for f‐SWNTs to prepare the moderately enhanced but lightweight phenolic composites. Furthermore, the incorporation of f‐SWNTs does not limit the application of phenolic resin as insulation material. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6135–6144, 2009     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalysen der mer‐Trihalogeno‐tris‐Pyridin‐Osmium(III)Komplexe mer‐[OsX3Py3], X = Cl,Br, I

Synthesis, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analyses of the mer ‐Trihalogeno‐tris‐Pyridine‐Osmium(III) Complexes mer‐[OsX₃Py₃], X = Cl, Br, I By reaction of the hexahalogenoosmates(IV) with pyridine and iso‐amylalcohol mer‐trihalogeno‐tris‐pyridine‐osmium(III) complexes are formed and purified by chromatography. X‐ray structure determinations on single crystals have been performed of mer‐[OsBr₃Py₃] (monoclinic, space group P2₁/n, a = 9.098(5), b = 12.864(5), c = 15.632(5) Å, β = 90.216(5)°, Z = 4) and mer‐[OsI₃Py₃] (monoclinic, space group P2₁/n, a = 9.0952(17), b = 13.461(4), c = 15.891(10), β = 91.569(5)°, Z = 4). The pyridine rings are twisted propeller‐like against the N₃ meridional plane with mean angles of 49° (Cl), 46° (Br), 44° (I). Based on the molecular parameters of the X‐ray structure determinations and assuming C₂ point symmetry, the IR and Raman spectra are assigned by normal coordinate analysis. Due to the stronger trans influence of pyridine as compared with the halide ligands for N'–Os–X ^· axes significantly different valence force constants are observed in comparison with symmetrically coordinated octahedron axes: f_d(OsCl) = 1.74, f_d(OsCl^·) = 1.49, f_d(OsBr) = 1.43, f_d(OsBr ^· ) = 1.18, f_d(OsI) = 0.99, f_d(OsI ^· ) = 0.96, f_d(OsN) between 1.96 and 2.07 and f_d(OsN') between 2.13 and 2.32 mdyn/Å.     

Design,synthesis, and antimicrobial activity of some new pyrazolo[3,4‐d]pyrimidines

2‐Benzyl‐ and 2‐aryloxymethyl‐3‐amino‐1‐phenyl‐pyrazolo[3,4‐d]pyrimidine‐4‐ones 5a–f have been synthesized by reacting the corresponding arylacetylamino derivatives 3a–f with hydrazine hydrate. Thionation of compounds 5d–f by action of P₂S₅ in pyridine yielded 2‐aryloxy‐methyl‐3‐amino‐1‐pheny‐lpyrazolo[3,4‐d]pyrimidin‐4‐thions 6a–c . 2,5‐Diphenyl‐2,3‐dihydro‐1H‐pyrazolo[5′,1′:4:5]pyrazolo[3,4‐d]pyrimidine‐8‐one ( 8 ) was also obtained via reaction of ethyl‐2‐cinnamoylamino‐1‐phenyl‐pyrazole‐4‐car‐boxylate ( 7 ) with hydrazine hydrate. The prepared compounds were screened in vitro for their antimicrobial activity. Some of the tested compounds were found to be active at 100 μg/ml compared with reference compounds (Ampicillin and Trivid) as antibacterial agents and claforan as antifungal agent. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:530–534, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10187     

First-principles relativistic calculation for 4f-5d transition energy of Ce in various fluoride hosts

In this paper, we investigated the 4f-5d transition energy of Ce³⁺ in various fluoride hosts based on the first-principles discrete-variational Dirac-Slater (DV-DS) calculations using Slater's transition-state theory. Especially, we focused on the lowest energy peak (1st peak) of 4f-5d transition for Ce³⁺ impurities. As the host crystals, we adopted the 15 fluorides, for which the experimental data of the lowest energy peak (1st peak) in 4f-5d transitions were available from literature except for NaMgF₃ and BaMgF₄. A high correlation between the experimental 1st peak energies and the theoretical ones was obtained which suggests a possibility to predict the 4f-5d transition energy of Ce³⁺ in various fluoride hosts using the first-principles calculation.     

Direct measurement of the nitrogen content by XPS in self‐passivated TaNx thin films

The nitrogen content in tantalum nitride (TaN_x) thin films, where x indicates that TaN_x is not generally stoechiometric, can be measured directly by XPS. This is the purpose of the present study. However, the XPS spectra of TaN_x present electron energy loss spectroscopy (EELS) peaks that lead to a complex peak fitting, particularly for self‐passivated thin films. A complete peak fitting procedure based upon Tougaard's background, the Doniach‐Sunjic Function and EELS peaks, is presented. It is applied to two self‐passivated TaN_x thin films elaborated by reactive sputtering and presenting a different nitrogen content. The physical properties of these surfaces are interpreted in terms of Ta 4f_7/2 chemical states directly dependent on the nitrogen content. The main results are discussed and improvements are proposed to the method. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis of 1,3,4‐Oxadiazole Acyclo C‐Nucleosides Bearing 5‐Methylthio{7‐substituted‐1,2,4‐triazolo[1,5‐d]tetrazol‐6‐yl}moieties

Oxidative cyclization of the sugar hydrazones ( 3_a‐f ) derived from {7H‐1,2,4‐triazolo[1,5‐d]tetrazol‐6‐ylsulfanyl}acetic acid hydrazide ( 1 ) and aldopentoses 2_a‐c or aldohexoses 2_d‐f with bromine in acetic acid in the presence of anhydrous sodium acetate, followed by acetylation with acetic anhydride gave the corresponding 2‐(per‐O‐acetyl‐alditol‐l‐yl)‐5‐methylthio{7H‐1,2,4‐triazolo[1,5‐d]tetrazol‐6‐yl}‐1,3,4‐oxadiazoles ( 5_a‐f ). Condensative cyclization of the sugar hydrazones ( 3_a‐f ) by heating with acetic anhydride gave the corresponding 3‐acetyl‐2‐(per‐O‐acetyl‐alditol‐1‐yl)‐2,3‐dihydro‐5‐methylthio{7‐acetyl‐1,2,4‐triazolo[1,5‐d]tetrazol‐6‐yl}‐1,3,4‐oxadiazoles ( 11_a‐f ). De‐O‐acetylation of the acyclo C‐nucleoside peracetates ( 5 and 11 ) with methanolic ammonia afforded the hydrazono lactones ( 7 ) and the acyclo C‐nucleosides ( 12 ), respectively. The structures of new oxadiazole derivatives were confirmed by analytical and spectral data.     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalysen der Tetrahalogeno‐bis‐Pyridin‐Osmium(III)‐Komplexe cis‐(n‐Bu4N)[OsCl4Py2] und trans‐(n‐Bu4N)[OsX4Py2], X = Cl,Br

Synthesis, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analyses of the Tetrahalogeno‐bis‐Pyridine‐Osmium(III) Complexes cis ‐( n ‐Bu₄N)[OsCl₄Py₂] and trans ‐( n ‐Bu₄N)[OsX₄Py₂], X = Cl, Br By reaction of (n‐Bu₄N)₂[OsX₆], X = Cl, Br, with pyridine and (n‐Bu₄N)[BH₄] tetrahalogeno‐bis‐pyridine‐osmium(III) complexes are formed and purified by chromatography. X‐ray structure determinations on single crystals have been performed of cis‐(n‐Bu₄N)[OsCl₄Py₂] ( 1 ) (triclinic, space group P1, a = 9.4047(9), b = 10.8424(18), c = 17.007(2) Å, α = 71.833(2), β = 81.249(10), γ = 67.209(12)°, Z = 2), trans‐(n‐Bu₄N)[OsCl₄Py₂] ( 2 ) (orthorhombic, space group P2₁2₁2₁, a = 8.7709(12), b = 20.551(4), c = 17.174(4) Å, Z = 4) and trans‐(n‐Bu₄N)[OsBr₄Py₂] ( 3 ) (triclinic, space group P1, a = 9.132(3), b = 12.053(3), c = 15.398(2) Å, α = 95.551(18), β = 94.12(2), γ = 106.529(19)°, Z = 2). Based on the molecular parameters of the X‐ray structure determinations and assuming C₂ point symmetry for the anion of 1 and D_2h point symmetry for the anions of 2 and 3 the IR and Raman spectra are assigned by normal coordinate analysis. The valence force constants of 1 are in the Cl–Os–Cl axis f_d(OsCl) = 1.58, in the asymmetrically coordinated N′–Os–Cl ^· axes f_d(OsCl ^· ) = 1.45, f_d(OsN′) = 2.48, of 2 f_d(OsCl) = 1.62, f_d(OsN) = 2.42 and of 3 f_d(OsBr) = 1.39 and f_d(OsN) = 2.34 mdyn/Å.     

Triazènes. Etude XPS. et 1H-RMN. des complexes mercuriques des diaryl-1,3-triazènes

XPS. and ¹H-NMR. spectra of 1,3-diaryltriazenes complexes of Hg(II) The core binding energies C 1s, N 1s, Hg 4f_7/2, Hg 4f_5/2 in 7 symmetrical p-substituted 1,3-diphenyltriazenes complexes of Hg(II) have been measured by XPS. Within the limits of experimental error (± 0.2 eV) only one N 1s signal could be detected. This indicates the equivalence of the 3 N-atoms. Invariance of C 1s, N 1s, Hg 4f_7/2, Hg 4d_5/2 signals with the para substituents on the phenyl ring is explained on the basis of ionic character in the Hg, N bond. These results are corroborated by the ¹H-NMR. spectra.     

Kristallstruktur,Schwingungsspektren und Normalkoordinatenanalyse von (n‐Bu4N)2[{Ru(NO)ClI2}2(μ‐I2)] · 2 I2

Crystal Structure, Vibrational Spectra, and Normal Coordinate Analysis of ( n ‐Bu₄N)₂[{Ru(NO)ClI₂}₂(μ‐I₂)] · 2 I₂ By treatment of (n‐Bu₄N)₂[Ru(NO)I₅] with (n‐Bu₄N)Cl in dichloromethane (n‐Bu₄N)₂[{Ru(NO)ClI₂}₂(μ‐I₂)] is formed. The X‐Ray structure determination on a single crystal of (n‐Bu₄N)₂[{Ru(NO)ClI₂}₂(μ‐I₂)] · 2 I₂ (monoclinic, space group I 2/a, a = 20.446(6), b = 11.482(8), c = 27.225(3) Å, β = 107.51(4)°, Z = 4) reveals a dinuclear iodine bridged structure, in which the chlorine atoms are trans positioned to the nitrosyl groups. The low temperature IR and Raman spectra have been recorded of (n‐Bu₄N)₂[{Ru(NO)ClI₂}₂(μ‐I₂)] · 2 I₂ and are assigned by normal coordinate analysis. A good agreement between observed and calculated frequencies is achieved. The valence force constants are f_d(NO) = 14.08, f_d(RuN) = 5.58, f_d(RuCl) = 1.52, f_d(RuI_t) = 0.90 and f_d(RuI_b) = 0.76 mdyn/Å.     

X‐ray photoelectron spectroscopy and the pattern recognition method—their application to surface studies in CoPd alloys

In the present work, polycrystalline CoPd alloys in varying range of bulk atomic percent composition (Co30Pd70, Co50Pd50 and Co70Pd30) are investigated by means of X‐ray photoelectron spectroscopy (XPS). The results of conventional XPS quantitative multiline (ML) approach are compared to the results obtained on the basis of XPS lines shape analysis, where the selected XPS or X‐ray induced Auger electron (XAES) transitions, are processed using the pattern recognition method known as the fuzzy k‐nearest neighbour (fkNN) rule. The fkNN rule is applied to the following spectra line shapes: Pd MNV, Co 2p, Co LMM, Pd 3d and valence band, analysing electrons in a varying range of selected kinetic energies. Both methods showed the surface segregation of Pd in Co30Pd70 and Co50Pd50 alloys. The results of the ML, the binding energy shift (ΔBE) analysis and the fkNN rule remained in agreement. Discrepancies in quantitative results obtained using different approaches are discussed within the accuracy of the applied methods, differences due to mean escape depth (MED) of electrons in considered transitions, their depth distribution function, the sensitivity of electron transition line shape on the environmental change (weaker effect for the inner shell transitions, and stronger effect for the outer shell transitions and Auger electron spectroscopy (AES) electrons transitions) and the non‐uniform depth profile concentrations. Copyright © 2005 John Wiley & Sons, Ltd.     

XPS calibration study of thin‐film nickel silicides

This paper presents a systematic X‐ray photoelectron spectroscopy (XPS)study of the Ni silicides Ni₃Si, Ni₃₁Si₁₂, Ni₂Si, NiSi and NiSi₂ produced by annealing of sputtered thin films. The in situ XPS study focuses on both the core level peaks and Auger peaks. The peak positions, shapes, satellites as well as Auger parameters are compared for different silicides. The factors that influence the Ni core level peak shifts are discussed. The Ni 2p_3/2 peak shape and satellites are correlated with the valence band structure. The effect of argon ion etching on surface composition and chemical states is also investigated. Copyright © 2009 John Wiley & Sons, Ltd.     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von (n‐Bu4N)2[PtX4(ox)], X = Cl,BR

Synthesis, Crystal Structure, Vibrational Spectra, and Normal Coordinate Analysis of (n‐Bu₄N)₂[PtX₄(ox)], X = Cl, Br By oxidation of (n‐Bu₄N)₂[PtX₂(ox)], X = Cl, Br, with Cl₂ or Br₂ in dichloromethane (n‐Bu₄N)₂[PtCl₄(ox)] ( 1 ) and (n‐Bu₄N)₂[PtBr₄(ox)] ( 2 ) are formed. The crystal structure of [(C₅H₅N)₂CH₂][PtCl₄(ox)] (monoclinic, space group C2/m, a = 15.562(1), b = 13.779(1), c = 10.168(1)Å, ß = 128.099(9)°, Z = 4) reveals complex anions with nearly C_2v point symmetry. The bond lengths in the Cl′‐Pt‐O^˙ axes are Pt‐Cl′ = 2.287 and Pt‐O^˙ = 2.048 and in the Cl‐Pt‐Cl axis Pt‐Cl = 2.314Å. The oxalato ligand is nearly plane with an O‐C‐C‐O torsion angle of 0.5°. In the vibrational spectra the PtX stretching vibrations are observed at 328 and 353 ( 1 ) and 201 and 212 cm^—1 ( 2 ). The PtX′ modes appear at 360 and 343 ( 1 ) and 227 and 238 cm^—1 ( 2 ). The PtO^˙ stretching vibrations are coupled with internal modes of the oxalato ligands and appear in the range of 400—800 cm^—1. Based on the molecular parameters of the X‐ray determination ( 1 ) and estimated data ( 2 ) the IR and Raman spectra are assigned by normal coordinate analysis. The valence force constants are f_d(PtCl) = 2.08, f_d(PtCl′) = 2.29, f_d(PtBr) = 1.56, f_d(PtBr′) = 2.02 and f_d(PtO^˙) = 2.46 ( 1 ) and 2.35 mdyn/Å ( 2 ). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved. The NMR shifts are δ(¹⁹⁵Pt) = 5623.0 ( 1 ) and 4536.1 ( 2 ).     

Catalytic Oxidative Cyclocondensation of o‐Aminophenols to 2‐Amino‐3H‐phenoxazin‐3‐ones

The catalytic oxidative cyclocondensation of the o‐aminophenols 1a–f was investigated. The oxidants used were air/laccase, H₂O₂/horseradish peroxidase, H₂O₂/ebselen (3), and TBHP/diphenyl diselenide 4. The products obtained were 2‐amino‐3H‐phenoxazin‐3‐one—questiomycin A, its derivative 2b, and cinnabarinic acid and actinocin (2c,d). Substrates with methyl groups at 4 and 5 positions of benzene ring were converted to different dihydrophenoxazinones 2g,h. Compounds having chlorine atoms at the same positions underwent oxidation to planar phenoxa-zinones 2e,f with elimination of one hydrochloride molecule.     

Kristallstrukturen,Schwingungsspektren und Normalkoordinatenanalyse von fac‐(Et4N)[OsF3Cl3] und fac‐(Et4N)[IrF3Cl3]

Crystal Structures, Vibrational Spectra and Normal Coordinate Analysis of fac ‐(Et₄N)[OsF₃Cl₃] and fac ‐(Et₄N)[IrF₃Cl₃] By careful oxidation of the pure fluorochloroosmates(IV) or ‐iridates(IV) with BrF₃ or KBrF₄ in dichloromethane the mixed pentavalent complex anions fac‐[OsF₃Cl₃]^– and fac‐[IrF₃Cl₃]^– are formed. X‐ray structure determinations on single crystals have been performed of cis‐(Et₄N)[OsF₃Cl₃] ( 1 ) (orthorhombic, space group Pbca, a = 11.225(5), b = 12.020(5), c = 21.873(5) Å, Z = 8) and fac‐(Et₄N)[IrF₃Cl₃] ( 2 ) (orthorhombic, space group Pbca, a = 11.269(10) b = 12.049(1), c = 21.801(3) Å, Z = 8). Based on the molecular parameters of the X‐ray determinations the IR and Raman spectra for the anion of 1 and 2 have been assigned by normal coordinate analysis. The Osmium compound exhibits slightly higher valence force constants as compared with the Iridium complex: f_d(OsF) = 3.25, f_d(IrF) = 3.25, f_d(OsCl) = 2.35 and f_d(IrCl) = 2.25 mdyn/Å.     

An Expedient Method for the Synthesis of 1,2,4‐Triazolo‐fused 1,5‐Benzodiazepine, 1,5‐Benzoxazepine,and 1,5‐Benzothiazepine Scaffolds: A Novel Seven‐membered Ring System of Biological Interest

New heterocyclic compounds 1‐(3‐methyl‐9H‐dibenzo[b,f][1,2,4]triazolo[4,3‐d][1,4]diazepin‐6‐yl)ethanone 8a , 1‐(3‐methyldibenzo[b,f][1,2,4]triazolo[4,3‐d][1,4]oxazepin‐6‐yl)ethanone 8b , and 1‐(3‐methyldibenzo[b,f][1,2,4]triazolo[4,3‐d][1,4]thiazepin‐6‐yl)ethanone 8c are synthesized from benzodiazepinone, benzoxazepinone, and benzothiazepinone derivatives. These heterocyclic scaffolds have wide medicinal importance. Best results were obtained in antibacterial screening against Escherichia coli, Enterobacter cloacae, and Staphylococcus aureus and antifungal screening against Candida albicans and Fusarium oxysporum. 1,1‐Diphenyl‐2‐picrylhydrazyl radical scavenging activities of compounds 6c , 7c , and 8c were tested in doses 10, 20, 30, 40, and 50 μg/mL and were expressed as IC₅₀ values and percent of inhibition with means ± standard deviation of three different concentrations of synthesized compounds. The assignment of the structures of synthesized compounds was made by thin‐layer chromatography, elemental analysis, IR, ¹H‐NMR, ¹³C‐NMR, and liquid chromatography–mass spectrometry.     

Core level studies of calcite and dolomite

Conventional X‐ray photoelectron spectroscopy (XPS) and synchrotron‐based X‐ray photoelectron spectroscopy (HRXPS) have been used to study Iceland spar calcite (CaCO₃) and dolomite (CaMg(CO₃)₂). The obtained full widths at half maximum (FWHMs) are mostly narrower than in the previous results, which together with the symmetry of the fitted peaks indicate effective neutralisation of surface charging. Some previously unidentified features observed in the Ca 2p, C 1s and O 1s spectra of calcite have been suggested to be bulk plasmons. Also, surface core level shifts in Ca 2p (in calcite) and Mg 2p (in dolomite) spectra have been obtained and found to be consistent between XPS and HRXPS measurements. A peak attributed to carbide (CaC₂) has been suggested to indicate beam‐assisted interaction with hydrocarbons found on the surface. Copyright © 2014 John Wiley & Sons, Ltd.     

A novel shape memory poly(ε‐caprolactone) network via UV‐triggered thiol‐ene reaction

A facile method to prepare shape memory polymers crosslinked by SiO₂ is described. A series of biodegradable shape memory networks were obtained through thiol‐ene reaction triggered by UV irradiation between surface‐thiol‐modified SiO₂ nanoparticles and end‐acrylate poly (ε‐caprolactone) (PCL). The highly selective thiol‐ene reaction ensured a uniform distribution of PCL chains between crosslinkers, contributing well‐defined network architecture with enhanced mechanical and shape‐memory properties. Thiol‐functionalized silica nanoparticle was characterized by using FTIR and XPS analysis, and ¹H NMR spectra was used to confirm the successful modification of terminal hydroxyl group of PCL diol. Surface‐modified silica particles were found well dispersible in acrylate‐capped PCL supported by SEM. Thermal and crystalline behaviors of the obtained polymers were analyzed by DSC and XRD, and DMA measurement proved good mechanical property. The shape memory behavior and tensile strength was somewhat tunable by the length of PCL. Acceptably, sample SiO₂‐SMP2k presented 99% recovery ratio and 97% shape fixity, and its relatively high tensile strength showed an attractive potential for biomedical application. Finally, a possible molecular mechanism accounting for the shape memory property was illustrated. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 692–701