80,330 research outputs found
EXAFS, DFT, light-induced nucleobase binding, and cytotoxicity of the photoactive complex cis-[Ru(bpy)2(CO)Cl]+
Get PDFThe aqueous photochemistry of cis-[Ru(bpy)2(CO)Cl]+ (1) was investigated at 310 K and under visible light (white) irradiation by NMR and ESI-HR-MS. Complex 1 releases a Cl ligand, coordinates a solvent molecule, and forms the complex cis-[Ru(bpy)2(CO)(H2O)]2+ (2). Also, irradiation experiments were performed in the presence of the nucleobase derivatives 9-ethylguanine (9-EtG) and 9-ethyladenine (9-EtA). Formation of Ru-9-EtG adducts was observed after 3 h irradiation by NMR and HR-MS, while only very small amounts of a Ru-9-EtA adduct could be detected by HR-MS. Solution structural data were obtained by X-ray absorption spectroscopy (XAS) for both 1 and 2. EXAFS gave a Ru−Cl distance of 2.416(7) Å for 1 and a Ru−OH2O distance of 2.102(6) Å for 2. DFT and TDDFT were employed to study the photophysical and photochemical properties of 1. Calculations show that dissociative metal-centered states can be related to the light-induced release of a Cl ligand and subsequent coordination of a solvent molecule. The compound showed no antiproliferative activity in three human carcinoma cell lines (lung, bladder, pancreas) under the testing conditions, either with or without irradiation with UV light
Double Exchange Interaction Between Mn3+ and Ru4+ Ions in La1-x Sr (x) Mn1-x Ru (x) O-3
No full textTo study the magnetic interaction between Mn3+ and Ru4+, we designed and synthesized a series of samples La1-x Sr (x) Mn1-x Ru (x) O-3 (0 a parts per thousand currency signx a parts per thousand currency sign 0.80), in which Mn and Ru ions remain as Mn3+ and Ru4+, respectively. The structural, magnetic, and transport properties of polycrystalline La1-x Sr (x) Mn1-x Ru (x) O-3 (0 a parts per thousand currency signx a parts per thousand currency sign 0.80) were investigated. Measurements of magnetization show that Ru4+ substitution induces and enhances ferromagnetism as xa parts per thousand currency sign 0.30. According to measurements of electronic conductivity, all doping samples show the insulating behaviors without metal-insulation transition. However, with increasing Ru4+ substitution, resistivity decreases and a shoulder appears in the rho(T) curves at around corresponding Curie temperature for 0.10 a parts per thousand currency sign x a parts per thousand currency sign 0.40. A large magnetoresistance effect is also observed in La0.60Sr0.40Mn0.60Ru0.40O3. All these phenomena is confirmed to be related with the double exchange interaction between Mn3+ and Ru4+ ions
Lattice oxygen evolution in rutile Ru(1−x)Ni(x)O2 electrocatalysts
No full textEfficient predictive tools for oxygen evolution reaction (OER) activity assessment are vital for rational design of anodes for green hydrogen production. Reaction mechanism prediction represents an important pre-requisite for such catalyst design. Even then, lattice oxygen evolution remains understudied and without reliable prediction methods. We propose a computational screening approach using density functional theory to evaluate the lattice oxygen evolution tendency in candidate surfaces. The method is based on a systematic assessment of the adsorption energies of oxygen evolution intermediates on model active sites with varying local structure. The power of the model is shown on model rutile (110) oriented surfaces of a) RuO2, b) Ru(1−x)Ni(x)O2 and c) Ru(1−x)Ti(x)O2. The model predicts a) no lattice exchange, b) lattice exchange at elevated electrode potentials and c) minor lattice exchange at elevated electrode potentials and high titanium content. While in the case of a) and b) the predictions provide sufficiently accurate agreement with experimental data, c) experimentally deviates from the above prediction by expressing a high tendency to evolve lattice oxygen at high titanium content (x = 0.20). This discrepancy can likely be attributed to the presence of structural defects in the prepared material, which are hard to accurately model with the applied methodology
Electrodeposition of arrays of Ru, Pt, and PtRu Alloy 1D metallic nanostructures
Get PDFArrays of Ru, Pt, and PtRu one dimensional 1D nanowires NWs and nanotubes NTs were prepared by electrodeposition through the porous structure of an anodic aluminum oxide AAO membrane. In each case, micrometer-long NW and NT were formed with an outer diameter of ca. 200 nm, close to the interior diameter of the porous AAO membrane. Arrays of NW and NT can be formed by varying the metallic salt concentration, the applied potential, and the conductivity of the electrolyte. The Ru and Pt deposition rates were measured in the various deposition conditions, using an electrochemical quartz crystal microbalance. The mechanisms responsible for the formation of Ru and Pt NW and NT are discussed based on the observed deposition rates and models found in the literature. Finally, it is shown that arrays of PtRu alloy NT and NW can be readily prepared and their compositions can be varied over the whole compositional range by changing the metallic salt concentration of the electrodeposition bath
Investigations on Low-Valent Group 8 and 9 Metalloradicals
Get PDFTetradentate, monoanionic, tris(phosphino)silyl ligands were chelated to group 8 and 9 transition metals to stabilize complexes with unusual oxidation states and/or geometries. Initial studies with the [SiPPh3]− ligand on ruthenium established the flexibility of this ancillary ligand in stabilizing complexes with strongly trans influencing ligands in trans dispositions. A related ligand scaffold, [SiPiPr3]−, was subsequently used to stabilize mononuclear complexes of Ru(I) and Os(I), the first examples to be isolated and thoroughly chracterized. EPR spectroscopy and DFT calculations supported their metalloradical character, and further studies highlighted their reactivity in both one- and two-electron redox processes. The ability of the [SiPiPr3]− scaffold to stabilize d7 metalloradicals of group 8 metals was extended to group 9 metals, and a series of d7 complexes of cobalt, rhodium, and iridium were synthesized in which their ancillary ligands, oxidation states, spin states, and geometry are conserved. Similar to the previously reported [SiPiPr3]Fe(N2) complex, the related [SiPiPr3]Ru(N2) complex was shown to exhibit N−N coupling of organic azides to yield azoarenes catalytically. Detailed mechanistic studies conclusively showed that the Ru(III) imide species, whose iron analog is the key intermediate in the [SiPiPr3]Fe system, is not involved in the mechanism for the [SiPiPr3]Ru system. Instead, a mechanism in which free nitrene is released during the catalytic cyle is favored. Finally, hybrid ligands with multiple thioether donors in place of phosphine donors on the [SiPR3]− scaffold were synthesized to stabilize a number of dinitrogen complex of iron. These complexes featured rare examples of S−Fe−N2 linkages
Counterion Effects in [Ru(bpy)3](X)2-Photocatalyzed Energy Transfer Reactions
No full textIn this report, we show that modification of the X counterions constitutive of [Ru(bpy)3](X)2 photocatalysts modulates their catalytic activities in intermolecular [2+2] cycloaddition reactions operating through triplet-triplet energy transfer (TTEnT). Particularly noteworthy is the dramatic impact observed in low-dielectric constant solvent over the excited state quenching coefficient, which varies by two orders of magnitude depending on whether X is a large weakly bound (BArF-) or a tightly bound anion (TsO-). In addition, the counterion identity also greatly affects the photophysical properties of the cationic ruthenium complex, with [Ru(bpy)3](BArF4)2 exhibiting the shortest 3MLCT excited state lifetime, highest excited state energy and photostability, enabling remarkably enhanced performance (up to >1000 TON at low 500 ppm catalyst loading) in TTEnT photocatalysis
Traces and shards of self-injury: Strange accounting with “Author X”
No full textIn this strange account autoethnography, three or four authors explore their lived experiences with self-injury. Strange accounting is both a post-modern style of text, and a method for keeping identities concealed when risks and secrets are in play. Author X, a post-modern place-keeper for an anonymous author who may or may not have contributed to this manuscript, introduces a new dimension and layer of concealment. With Author X in-play and under erasure, the reader will never be sure if there were three or four authors on this manuscript. Through strange accounting, a post-structuralist/postmodernist frame will be applied to understanding the self-injury experience. We frame self-injury as a social practice and, for some, an everyday norm, while remaining acutely aware of the stigma surrounding the topic of self-injury. Each of us, coupled with Author X, provide the others cover to trace stories of self-injury through the literature, our flesh, and our lives
Quaterpyridine Ligands for Panchromatic Ru(II) Dye Sensitizers
Get PDFA new general synthetic access to carboxylated quaterpyridines (qpy), of interest as ligands for panchromatic dyesensitized solar cell organometallic sensitizers, is presented. The strategic step is a Suzuki−Miyaura cross-coupling reaction,
which has allowed the preparation of a number of representative unsubstituted and alkyl and (hetero)aromatic substituted qpys.
To bypass the poor inherent stability of 2-pyridylboronic acid derivatives, we successfully applied N-methyliminodiacetic acid
(MIDA) boronates as key reagents, obtaining the qpy ligands in good yields up to (quasi)gram quantities. The structural,
spectroscopic (NMR and UV−vis), electrochemical, and electronic characteristics of the qpy have been experimentally and
computationally (DFT) investigated. The easy access to the bis-thiocyanato Ru(II) complex of the parent species of the qpy
series, through an efficient route which bypasses the use of Sephadex column chromatography, is shown. The bis-thiocyanato
Ru(II) complex has been spectroscopically (NMR and UV−vis), electrochemically, and computationally investigated, relating its
properties to those of previously reported Ru(II)−qpy complexes.“This document is the Accepted Manuscript version of a Published Work that appeared in final form in [The Journal of Organic Chemistry], copyright © American Chemical Society after peer review and technical editing by the publisher
Magnetic properties and microstructure of CoCrPtX (X=Re, Ru) and CoCrPt-oxide/Ru/NixPd100-x films
No full text本實驗使用直流磁控濺鍍系統，分成兩大部分：第一部份在室溫下鍍著NixPd100-x在Ni62.5Ta37.5合金薄膜上，並依序鍍上Ru及CoCrPt-oxide，目的增強Ru的織構進而使CoCrPt的織構變強，比較NixPd100-x對Ru及CoCrPt的影響。第二部分在CoCrPt中添加8 at% Re, Ru元素及3 at% Re元素，目的是為了藉由添加元素改善記錄層的磁性以及微結構，並提升Hc、Hn、Ku等磁性值。
第一部分在玻璃基板上鍍著膜層結構為CoCrPt(18 nm)/Ru(20 nm)/NiTa(10 nm)之薄膜以及CoCrPt(18 nm)/Ru(20 nm)/NixPd100-x(t nm)/ NiTa(10 nm)之薄膜，NiPd的成分分別為Ni20Pd80、Ni50Pd50、Ni80Pd20，選用與Ru晶格常數相互匹配的中間層材料NixPd100-x鍍著在NiTa合金薄膜上，再改變兩者之厚度(0、5、10和15 nm )，固定CoCrPt、中間層Ru的膜層厚度。從磁滯曲線圖顯示加入Ni20Pd80中間層，垂直繳頑磁力及磁晶異向能，分別為5.4 kOe及3.7*106 erg/cm3；加入Ni50Pd50中間層，垂直繳頑磁力及磁晶異向能，分別為5.7 kOe及4.1*106 erg/cm3；加入Ni80Pd20中間層，垂直繳頑磁力及磁晶異向能，分別為5.7 kOe及4.1*106 erg/cm3，比較NixPd100-x中間層，Ni20Pd80中間層更有效的增強了Ru(0002)織構強度進而增強了CoCrPt(0002)織構強度改善了其磁性◦
第二部分在玻璃基板上製備膜層結構為CoCrPtX(t nm)(X=8 at%Re, Ru)/Ru(20 m)/NiTa(10 nm)以及Co(CrX)Pt(t nm)(X=3 at%Re)/Ru(20 m)/NiW(10 nm)/NiTa(10 nm)，改變CoCrPt之膜層厚度(12、15、18和21 nm)。從磁滯曲線圖結果發現在CoCrPt中添加8 at% Re時，垂直矯頑力為5.4 kOe、成核場為2043 Oe、磁晶異向能為3.9*106 erg/cm3；在CoCrPt中添加8 at% Ru時，垂直矯頑力為4.2 kOe、成核場為1255 Oe、磁晶異向能為3.3*106 erg/cm3。相較於添加3 at% Re呈現較高垂直矯頑力為6.1 kOe、磁晶異向能為5.4*106 erg/cm3，從TEM微結構可以看到加入3 at% Re降低了晶粒團簇的現象。We used a DC magnetron sputtering system in the study. The experiment was divided into two parts. In the first part, we deposited NixPd100-x on Ni62.5Ta37.5 alloy at room temperature, and then sequentially deposited Ru and CoCrPt-oxide. Let the underlying purpose of Ru (0002) peak intensity increased and the texture of CoCrPt becomes stronger and improved vertical anisotropy of magnetic properties, compare the effects of NixPd100-x on Ru and CoCrPt. The second part is to add 8 at% Re, Ru and 3 at% Re elements in CoCrPt. The purpose is to improve the magnetic properties and microstructure of the recording layer by adding elements, and to increase magnetic values such as Hc, Hn, and Ku value.
The first part was CoCrPt(18 nm)/Ru(20 nm)/NiTa(10 nm) of the film and CoCrPt(18 nm)/Ru(20 nm)/NixPd100-x(t nm)/ NiTa(10 nm) of the film. The composition of NiPd is Ni20Pd80, Ni50Pd50, Ni80Pd20 respectively. The lattice constant of NixPd100-x thin film matched with Ru film. And then change the thickness of NixPd100-x (0, 5, 10 and 15 nm), fixed CoCrPt and Ru layer thickness. With Ni20Pd80, illustrates perpendicular magnetic anisotropy with out-of plane coercivity of 5.6 kOe and Ku was 3.9*106 erg/cm3. With Ni50Pd50, illustrates perpendicular magnetic anisotropy with out-of plane coercivity of 3.8 kOe and Ku was 3.2*106 erg/cm3. With Ni80Pd20, illustrates perpendicular magnetic anisotropy with out-of plane coercivity of 3.4 kOe and Ku was 1.8*106 erg/cm3. Comparing NixPd100-x intermediate layer, the Ni20Pd80 intermediate layer enhances the Ru (0002) texture and enhances the CoCrPt (0002) texture to improve its magnetic properties .
The second part was fixed CoCrPtX(t nm)(X=8 at%Re, Ru)/Ru(20 nm)/NiTa(10 nm) of the film and Co(CrX)Pt(t nm)(X=3 at%Re)/Ru(20 nm)/NiW(10 nm)/NiTa(10 nm) of the film, and then change the thickness of CoCrPt (12, 15, 18 and 21 nm). With 8 at% Re in CoCrPt film, the out-of-plane coercivity (Hc) is 5.0 kOe, the nucleation field (Hn) is 2043 Oe and magnetocrystalline anisotropy constant (Ku) is 3.9*106 erg/cm3. With 8 at% Ru in film, the out-of-plane coercivity (Hc) is 4.2 kOe, the nucleation field (Hn) is 1255 Oe and magnetocrystalline anisotropy constant (Ku) is 3.3*106 erg/cm3. As compared to with 3 at% Re in CoCrPt shows higher out-of-plane Hc value of 6.1 kOe and the Ku value of 5.4*106 erg/cm3. From the TEM microstructure could be seen to add the 3 at% Re interface layer, reducing the phenomenon of grain clusters to improve its magnetic properties.摘要 i
Abstract ii
目錄 iv
表目錄 vii
圖目錄 viii
第一章 緒論 1
1-1 前言 1
1-2 硬式磁碟機的簡介與發展 2
1-3 研究動機 8
第二章 基礎理論與文獻回顧 9
2-1 垂直式記錄媒體的膜層結構 9
2-1-1 吸附層(Adhesion layer) 9
2-1-2 軟磁層(Soft under layer) 10
2-1-3 中間層(Intermediate layer) 10
2-1-4 記錄層(Recording layer) 11
2-1-5 覆蓋層(Overcoat) 12
2-2 理論基礎 13
2-2-1 磁性材料 13
2-2-2 磁異向性 14
2-2-3 薄膜成長機制 18
2-3 文獻回顧 23
2-3-1 NiW薄膜中間層之文獻回顧 23
2-3-2 Pd中間層文獻回顧 28
2-3-3 Ta中間層文獻回顧 31
2-3-4 Ru中間層文獻回顧 33
2-3-5 CoCrPtX(X=Re, Ru, Mo…)記錄層文獻回顧 38
2-3-6 CoCrPt-SiO2記錄層文獻回顧 42
2-3-7 CoCrPt-oxide記錄層文獻回顧 44
第三章 實驗流程與儀器原理 47
3-1實驗流程 47
3-2靶材選擇 48
3-3基板選用和清洗 49
3-4薄膜濺鍍與樣品製備 51
3-4-1磁控濺鍍系統 51
3-4-2薄膜製備 53
3-4-3膜厚量測 54
3-4-4 TEM樣品製備 55
3-4-5元素分布 55
3-5 設備介紹與分析方法 56
3-5-1原子力顯微鏡(AFM) 56
3-5-2 X-ray繞射儀(XRD) 58
3-5-3震動樣品磁度儀(VSM) 61
3-5-4 穿透式電子顯微鏡(TEM) 63
3-5-5 精密離子打薄機(PIPS) 66
3-5-6 多功能離子聚焦束(FIB) 67
第四章 結果與討論 69
4-1 參考試片之X-ray繞射分析 71
4-2 NixPd100-x中間層之探討及比較 73
4-2-1 CoCrPt/Ru/Ni20Pd80(t nm)/NiTa之X-ray繞射分析 74
4-2-2 CoCrPt/Ru/Ni50Pd50(t nm)/NiTa之X-ray繞射分析 76
4-2-3 CoCrPt/Ru/Ni80Pd20(t nm)/NiTa之X-ray繞射分析 78
4-2-4 NixPd100-x中間層之CoCrPt磁性分析 79
4-2-5 NixPd100-x中間層之CoCrPt微結構分析 82
4-3 CoCrPtX (X=Re, Ru)紀錄層之探討及比較 85
4-3-1 CoCrPtRe(t nm)/Ru/NiTa之X-ray繞射分析 85
4-3-2 CoCrPtRu(t nm)/Ru/NiTa之X-ray繞射分析 87
4-3-3 CoCrPtX (X=Re, Ru)/Ru/NiTa之磁性質分析 88
4-3-4 CoCrPtX (X=Re, Ru)/Ru/NiW/NiTa之微結構分析 90
4-4 Co(CrX)Pt (X=Re)紀錄層之探討及比較 93
4-4-1 CoCrPt(t nm)/Ru/NiW/NiTa之X-ray繞射分析 94
4-4-2 CoCrPtRe(t nm)/Ru/NiW/NiTa之X-ray繞射分析 95
4-4-3 Co(CrX)Pt (X=Re)/Ru/NiW/NiTa之磁性質分析 96
4-4-4 Co(CrX)Pt (X=Re)/Ru/NiW/NiTa之微結構分析 98
第五章 結論 101
參考文獻 10
Coordinatively unsaturated ruthenium complexes as efficient alkyne-azide cycloaddition catalysts
Get PDFThe performance of 16-electron ruthenium complexes with the general formula Cp*Ru(L)X (in which L = phosphine or N-heterocyclic carbene ligand; X = Cl or OCH2CF3) was explored in azide−alkyne cycloaddition reactions that afford the 1,2,3- triazole products. The scope of the Cp*Ru(PiPr3)Cl precatalyst was investigated for terminal alkynes leading to new 1,5-disubstituted 1,2,3-triazoles in high yields. Mechanistic studies were conducted and revealed a number of proposed intermediates. Cp*Ru- (PiPr3)(η2-HCCPh)Cl was observed and characterized by 1H, 13C, and 31P NMR at temperatures between 273 and 213 K. A rare example of N,N-κ2-phosphazide complex, Cp*Ru(κ2-iPr3PN3Bn)Cl, was fully characterized, and a single-crystal X-ray diffraction structure was obtained. DFT calculations describe a complete map of the catalytic reactivity with phenylacetylene and/or benzylazide.Peer reviewe
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