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Odd-even effects in the structure and properties of aryl-substituted aliphatic self-assembled monolayers

Nano Research 2024年第5期17卷 4231-4243页

作者： Piotr Cyganik Andreas Terfort Michael Zharnikov Jagiellonian University Faculty of PhysicsAstronomy and Applied Computer ScienceSmoluchowski Institute of PhysicsŁojasiewicza 1130-348 KrakówPoland institut für Anorganische und analytische chemie Universität FrankfurtMax-von-Laue-Straße 760438 FrankfurtGermany Applied Physical Chemistry Heidelberg UniversityIm Neuenheimer Feld 25369120 HeidelbergGermany

Self-assembled monolayers(SAMs)represent an important tool in context of nanofabrication and molecular engineering of surfaces and *** properties of functional SAMs depend not only on the character of the tail groups at the SAM-ambient interface,but are also largely defined by their *** its turn,the latter parameter results from a complex interplay of the structural forces and a variety of other factors,including so called odd-even effects,*** of the SAM structure and properties on the parity of the number(odd or even)of individual building blocks in the backbone of the SAM *** most impressive manifestation of the odd-even effects is the structure of aryl-substituted alkanethiolate SAMs on Au(111)and Ag(111),in which,in spite of the fact that the intermolecular interaction is mostly determined by the aryl part of the monolayers,one observes a pronounced dependence of molecular inclination and,consequently,the packing density of the SAM-forming molecules on the parity of number of methylene units in the alkyl *** we review the properties of the above systems as well as address fundamental reasons behind the odd-even effects,including the existence of a so-called bending potential,which is frequently disregarded in analysis of the structure-building *** generality of the odd-even effects in SAMs is additionally supported by the recent data for SAMs on GaAs,scanning tunneling microscopy data for SAMs on Ag(111),and the data for the monolayers with selenolate and carboxyl anchoring groups on Au(111)and Ag(111).The implications of these effects in terms of the control over the packing density and orientation of the tail groups at the SAM-ambient interface,structural perfection,polymorphism,temperature-driven phase transitions,and SAM stability toward such factors as ionizing radiation,exchange reaction,and electrochemical desorption are *** implications place the odd-even effects as an important tool

关键词： self-assembled monolayers molecular films surface and interface engineering odd-even-effects

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Photoinduced E to Z isomerization of tetraphenylethylene derivatives within organometallic supramolecular assemblies

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Science China Chemistry 2021年第10期64卷 1709-1715页

作者： Xiao-Xu Liu Yang Li Xin Li F.Ekkehardt Hahn Ying-Feng Han College of Chemistry and Materials Science Northwest UniversityXi'an 710127China institut fiir Anorganicshe und analytische chemie Westfalische Wilhelms-Universitat Munster Corrensstrasse 30 48149 MunsterGermany

Isolation of E-1,2-bis(4-bromophenyl)-1,2-diphenyl-ethylene from the E/Z isomer mixture obtained by a Mc Murry coupling reaction and reaction of this isomer with imidazole followed by N-alkylation with n Bu Br and anion exchange yielded the bisimidazolium tetraphenylethylene(TPE)derivative H_(2)-E-1(PF_(6))_(2).The reaction of H_(2)-E-1(PF_(6))_(2) with Ag_(2)O yielded the dinuclear metallarectangle[Ag_(2)(E-1)2](PF_(6))_(2) where the two bis-NHC donors E-1 bridge two silver *** of[Ag_(2)(E-1)2](PF_(6))_(2) leads to E/Z isomerization of the di-NHC ligand and formation of Z-1 in the mononuclear complex[Ag(Z-1)]PF_(6).Demetallation of the di-NHC ligand with NH_(4)Cl/NH_(4)PF_(6) yielded bisimidazolium salt H_(2)-Z-1(PF_(6))_(2).The unique isomerization of the E-TPE derivative into its Z-isomer via metal complex formation/irradiation/demetallation cannot be achieved by irradiation of the individual imidazolium *** emissive properties of the TPE complexes[Ag_(2)(E-1)2](PF_(6))_(2) and[Ag(Z-1)]PF_(6) have been investigated.

关键词： N-heterocyclic carbene tetraphenylethylene photochemical isomerization fluorescence EZI process

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Microwave Induced Plasma Source for Analytical Applications： Experimental and Simulation Study

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Journal of Chemistry and Chemical Engineering 2011年第6期5卷 502-513页

作者： Margarita Baeva Andre Bose Jorg Ehlbeck Wolfgang Buscher Rasmus Janzen Leibniz institut fiir Plasmaforschung und Technologie Felix-Hausdorff-Strasse 2 D-17489 Greifswald Germany institut fur anorganisehe und analytische chemie Correnstrasse 28/30 D-48149 Munster Germany

In this work, experiment investigations and simulation studies of a waveguide-based microwave plasma source operated at 2.45 GHz in atmospheric pressure helium gas are presented. The plasma source has been designed in conjunction with a gas spectrograph as a speciation analysis tool. Emitted He spectra are observed for gas flow rates between （0.2-1） L/min and microwave power in the range （15-150） W. The results obtained demonstrate maximum excitation temperature of about 3800 K and gas temperature of about 2000 K. Mixtures containing small amounts of mercury atoms are considered and the resonant emission of Hg atoms at 253.56 nm is detected. The spectroscopic measurements are completed with a collisional radiative model delivering the electron density and temperature, the amplitude of the electric microwave field, and the population of the excited atomic states for a given absorbed power and gas temperature, The electromagnetic field distribution in the plasma source is obtained by solving Maxwell＇s equations. Electric field strength of several 10^5 V/m is obtained that agrees well with the results of the collisional radiative model. The calculated and measured line intensity ratios of He spectral lines agree within 300/0-40%.

关键词： Microwave plasma atmospheric pressure Helium Mercury detection emission spectroscopy modeling.

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Aromatic self-assembled monolayers with pentafluoro-λ^(6)-sulfanyl(−SF_(5))termination:Molecular organization and charge transport properties

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Nano Research 2023年第5期16卷 7991-8002页

作者： Yangbiao Liu Marc Zeplichal Sonja Katzbach Adrian Wiesner Saunak Das reas Terfort Michael Zharnikov Angewandte Physikalische chemie Universität HeidelbergIm Neuenheimer Feld 253D-69120 HeidelbergGermany institut für Anorganische und analytische chemie Johann Wolfgang Goethe Universität FrankfurtMax-von-Laue-Straße 7D-60438 Frankfurt am MainGermany

A series of molecules with oligophenylene backbone,thiolate anchoring group,pentafluoro-λ^(6)-sulfanyl(−SF_(5))tail group was synthesized and used as precursors to form self-assembled monolayers(SAMs)on Au(111)*** resulting SAMs feature dense molecular packing,upright molecular orientation,chemically homogeneous SAM-ambient interface,comprised entirely of the−SF_(5)*** SAMs exhibit exceptional wetting and electrostatic properties,showing advancing water contact angles up to 103°and work function values up to 5.96 eV—probably the highest values reported for any aromatic monolayers on *** also feature a comparably low value of the tunnelling decay coefficient(0.38±0.07Å^(−1)),typical of oligophenylene backbone,which is not affected by the introduction of the−SF_(5)*** latter also hardly affects the current densities at a specific bias compared to analogous monolayers with other electronegative tail *** superior electrostatic and good charge transport properties of the designed,SF_(5)-terminated SAMs make them potentially useful for interface engineering in organic electronics and photovoltaics.

关键词： backbone charge electrostatic

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The 3,4-dimethoxybenzyl group as solubilizing protective group for the in situ deprotection/deposition of extended aromatic thiolate monolayers

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Nano Research 2023年第1期16卷 1695-1702页

作者： Adrian Wiesner Sonja Katzbach Dariusz Bebej Martina Dettenhöfer Michael Zharnikov Andreas Terfort institut für Anorganische und analytische chemie Johann Wolfgang Goethe Universität FrankfurtMax-von-Laue-Straße 7Frankfurt am Main D-60438Germany Angewandte Physikalische chemie Universität HeidelbergIm Neuenheimer Feld 253Heidelberg D-69120Germany

While self-assembled monolayers(SAMs)of aromatic thiolates are frequently used in a wide range of applications,their formation is often hampered by the low solubilities of their *** we introduce the 3,4-dimethoxybenzyl group as a protective group for the thiol moiety,which increases the solubility and stability of the precursor,but becomes cleaved off during monolayer formation,especially at elevated temperature(60°C)and in presence of protons(trifluoroacetic acid).For a series of substituted terphenylthiols as model systems,it could be demonstrated by using ellipsometry,infrared-reflection absorption spectroscopy,and scanning-tunneling microscopy that the resulting SAMs have the same structure and quality as the ones obtained from the respective unprotected *** protective group has the additional advantage to be stable under Pdcatalyzed C–C bond formation reaction conditions,facilitating the syntheses of the respective precursors.

关键词： self-assembled monolayers protective group solubility scanning-tunneling microscopy infrared-reflection absorption spectroscopy

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过渡金属重卡拜的合成、结构与反应性

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化学进展 2012年第2期24卷 318-326页

作者：吴限 institut far Anorganische und analytische chemie Technische Universitit Braunschweig Hagenring 30 D-38106 Braunschweig Germany

过渡金属硅卡拜、锗卡拜、锡卡拜和铅卡拜是过渡金属分别与硅、锗、锡和铅之间形成三键的化合物。自从1996年首次发现钼锗卡拜以来,相继得到了一系列过渡金属锗卡拜、锡卡拜和铅卡拜化合物,而首例过渡金属硅卡拜则于2010年得以成功制备... 详细信息

过渡金属硅卡拜、锗卡拜、锡卡拜和铅卡拜是过渡金属分别与硅、锗、锡和铅之间形成三键的化合物。自从1996年首次发现钼锗卡拜以来,相继得到了一系列过渡金属锗卡拜、锡卡拜和铅卡拜化合物,而首例过渡金属硅卡拜则于2010年得以成功制备,标志着过渡金属与第14族元素之间形成三键的空白被全部填满。这些化合物的出现大大丰富和完善了过渡金属主族元素化学在成键、结构和反应方面的内容,引起化学界的重视。本文结合这方面最新的实验研究进展,系统全面总结了这些化合物的合成、结构和反应性,并对该领域的发展前景作了讨论。

关键词：过渡金属硅卡拜锗卡拜锡卡拜铅卡拜

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N-heterocyclic carbene-stabilized metal nanoparticles within porous organic cages for catalytic application

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National Science Review 2022年第6期9卷 135-142页

作者： Tong Liu Sha Bai Le Zhang F.Ekkehardt Hahn Ying-Feng Han Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education Xi'an Key Laboratory of Functional Supramolecular Structure and Materials College of Chemistry and Materials ScienceNorthwest University institut für Anorganicshe und analytische chemie Westf?lische Wilhelms-Universit?t Münster

Tuning the surface-embellishing ligands of metal nanoparticles(NPs) is a powerful strategy to modulate their morphology and surface electronic and functional features, impacting their catalytic activity and selectivity. In this work, we report the design and synthesis of a polytriazolium organic cage PIC-T, capable of stabilizing Pd NPs within its discrete cavity. The obtained material(denoted Pd@PCC-T) is highly durable and monodispersed with narrow particle-size distribution of 2.06 ± 0.02 nm, exhibiting excellent catalytic performance and recyclability in the Sonogashira coupling and tandem reaction to synthesize benzofuran derivatives. further investigation indicates that the modulation of N-heterocyclic carbene sites embedded in the organic cage has an impact on NPs’ catalytic efficiency, thus providing a novel methodology to design superior NP catalysts.

关键词： metal nanoparticle porous organic cage catalytic reaction N-heterocyclic carbene

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Hop-induced formation of ethyl esters in dry-hopped beer

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食物生产加工与营养(英文) 2020年第1期2卷 179-185页

作者： Sabrina Brendel Thomas Hofmann Michael Granvogl Lehrstuhl für Lebensmittelchemie und Molekulare Sensorik Technische Universität MünchenWissenschaftszentrum Weihenstephan für ErnährungLandnutzung und UmweltLise-Meitner-Straße 3485354 FreisingGermany institut für Lebensmittelchemie Fg.Lebensmittelchemie und Analytische Chemie(170a)Universität HohenheimFakultät für NaturwissenschaftenGarbenstraße 2870599 StuttgartGermany

Fruity smelling esters play an important role for the aroma of hops and beer and they have been characterized as key aroma compounds in different hop *** on the transfer of hop-derived compounds into beer during dry-hopping showed calculated transfer rates of different ethyl esters far above 100%,leading to the assumption that these esters must be newly *** investigate this formation,dry-hopping was imitated in water to eliminate the influence of the beer matrix on the formation of these ***,the formation of ethyl esters of 2-methylbutanoic acid,3-methylbutanoic acid,and methylpropanoic acid,induced by the addition of hops,was *** approaches inhibiting enzyme activities and experiments with different hop extracts might lead to the assumption that enzymes are involved in the formation of these esters,beside possible transesterification.

关键词： Hops Dry-hopping Beer Ethyl esters Aroma formation Radicals Enzymes

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过渡金属多烯烃配合物的合成与反应

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有机化学 1986年第1期 62-68页

作者： JrnMüller institut für Anorganische und analytische chemie der Technischen Universitt/Berlin W.Germany

一、在异丙基澳化镁存在下1,5-环辛二烯低价过渡金属氯化物的反应例如,三氯化铑与双烯烃反应可得到双烯烃氯化铑配合物,乙醇既是溶剂,又是还原剂。此外,等双烯烃也都可以与RhCl反应生成相应的配合物。1.1,5-环辛二烯氯化铑1与环多烯烃反... 详细信息

一、在异丙基澳化镁存在下1,5-环辛二烯低价过渡金属氯化物的反应例如,三氯化铑与双烯烃反应可得到双烯烃氯化铑配合物,乙醇既是溶剂,又是还原剂。此外,等双烯烃也都可以与RhCl反应生成相应的配合物。1.1,5-环辛二烯氯化铑1与环多烯烃反应1可与环多烯烃反应,生成1,5-环辛二烯铑烯丙基型配合物。由于苯的共振能较高,故1不能与它发生反应。

关键词：配合物多烯烃过渡金属过渡元素

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盐湖沉积物的穆斯堡尔效应研究

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盐湖研究 2004年第1期12卷 1-7,18页

作者：祁永唐 J.Ensling P.Guetlich 中国科学院青海盐湖研究所青海西宁810008 institut fuer Anorganische chemie und analytische chemie

对青海柴达木盆地察尔汗、昆特依盐湖以及新疆罗布泊盐湖一系列沉积物样品进行了穆斯堡尔效应的研究。对全部样品做了常温下的穆斯堡尔谱学测量,并对部分样品做了低温下的测量。从穆斯堡尔谱的解析结果可知,盐湖沉积物黏土矿中含二价铁... 详细信息

对青海柴达木盆地察尔汗、昆特依盐湖以及新疆罗布泊盐湖一系列沉积物样品进行了穆斯堡尔效应的研究。对全部样品做了常温下的穆斯堡尔谱学测量,并对部分样品做了低温下的测量。从穆斯堡尔谱的解析结果可知,盐湖沉积物黏土矿中含二价铁的主要矿物是绿泥石,在察尔汗盐湖样品中有少量菱铁矿;三价铁存在于多种矿物和非晶态的氢氧化物中;某些样品中含有少量的赤铁矿,它在常温下即出现磁有序。不同盐湖的沉积物样品和同一盐湖不同深度样品的含铁矿物组成及相对含量不同,Fe2+/Fe3+的比值也不同。这些结果可以反映出盐湖沉积过程中地球化学和环境及气候的变化。

关键词：盐湖沉积物穆斯堡尔效应含铁矿物

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