DOCSLIB.ORG

New Developments in Transition Metal Alkyl Chemistry

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
New Developments in Transition Metal Alkyl Chemistry New Developments in Transition Metal Alkyl Chemistry by David Armstrong A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Department of Chemistry University of Toronto © Copyright by David Armstrong 2018 New Developments in Transition Metal Alkyl Chemistry David Armstrong Doctor of Philosophy Department of Chemistry University of Toronto 2018 Abstract In the first section of this thesis, the synthesis and reactivity of the first reported palladium(IV) aryldiazenido complex is explored, as well as its relevance toward the potential for catalytic coupling cycles based on the Pd(II)/Pd(IV) redox pair. The synthesis was achieved by two-electron - oxidation of the anionic palladium(II) complex KPd(Tp*)Me2 (Tp* = hydridotris(3,5- dimethylpyrazolyl)borate) by an aryldiazonium cation. The resulting Pd(IV) complex could be cleanly isolated in good yields, is stable for weeks as a solid when kept cold, and decays in solution over a period of days at room temperature. The decomposition was studied in great depth by both NMR and EPR spectroscopy and it was determined that one-electron pathways were involved. From the synthesis of the Pd(IV) aryldiazenido complex, side reactions were observed whereby free Tp*- ligand could be modified via hydride abstraction by an aryldiazonium cation to form the elusive tris(pyrazolyl)borane which could be trapped and isolated as its acetone adduct in a Frustrated Lewis-pair type reaction. The resulting compound can act as a bidentate N-donor ligand with unusual axial steric bulk. Addition of a second equivalent of aryldiazonium cation further abstracts a 3,5-dimethylpyrazolide group to form a cationic intermediate which can again be trapped by acetone to form a C2-chiral cation. ii In the later chapters of this thesis, extensive work towards the synthesis of 1- and 2- adamantyl anion equivalents was explored, as well as their utility in the synthesis of transition metal adamantyl complexes. The development of new reliable synthetic methods to produce adamantyl magnesium and zinc compounds (including the unknown diadamantylzincs) was achieved, producing clean and shelf stable compounds. The applications of these adamantyl anions toward organometallic chemistry was investigated. It was observed that the diadamantylzinc compounds were particularly potent in transmetallation reactions, cleanly producing several new transition metal and main group adamantyl complexes. While compounds containing mercury, gold, bismuth, tungsten, and platinum have now been synthesized, those of particular interest have the potential for C-H bond activation chemistry and could open access to new compound classes of facially trifunctionalized adamantanes. iii Acknowledgments I would like to extend my gratitude toward Professor Ulrich Fekl for providing me the opportunity to not only complete this degree, but to take charge and make this research my own. Thanks to my parents Kim and Keith for instilling me with a desire to never stop learning, and to my sister Heather for always pushing me to be better. Thanks to the members of the Fekl lab past and present. My experience would not have been the same were it not for the atmosphere of friendship and support that has been ever present here. Lastly, I would like to thank Fioralba Taullaj for not only her constant support personally, but also for bringing an attitude of hard work and dedication to the lab which really inspired me to push beyond my bounds. iv Table of Contents Acknowledgments.......................................................................................................................... iv Table of Contents .............................................................................................................................v List of Tables ................................................................................................................................. ix List of Figures ..................................................................................................................................x List of Schemes ............................................................................................................................ xiii List of Abbreviations ................................................................................................................... xvi Contributions.............................................................................................................................. xviii Chapter 1 - Introduction ...................................................................................................................1 1.1 History of Metal Alkyl Chemistry .......................................................................................1 1.2 Why Are We Interested in Metal Alkyls? ............................................................................2 1.3 Decomposition of Metal Alkyls ...........................................................................................5 1.4 Synthesis of Metal Alkyls ....................................................................................................9 1.5 C-H Bond Activation and Functionalization .....................................................................13 1.6 Computational Chemistry ..................................................................................................16 1.7 Organization of this Thesis ................................................................................................18 1.8 References for Chapter 1 ...................................................................................................20 Chapter 2 - The First Palladium(IV) Aryldiazenido Complex – Relevance for C-C Coupling ....23 2.1 Abstract ..............................................................................................................................23 2.2 Introduction ........................................................................................................................23 2.3 Results and Discussion ......................................................................................................28 2.4 Conclusion .........................................................................................................................40 2.5 Experimental Section .........................................................................................................40 2.5.1 General Specifications ..............................................................................................40 2.5.2 Synthesis of 1,5-Cyclooctadiene Dimethyl Palladium(II) {Pd(COD)Me2)} ............41 2.5.3 Synthesis of Pd(Tp*)Me2(pmbd) ..............................................................................41 v 2.5.4 X-ray structure determination of Pd(Tp*)Me2(pmbd) ..............................................42 2.5.5 Thermolysis of Pd(Tp*)Me2(pmbd) in C6D6 ............................................................44 2.5.6 Thermolysis of Pd(Tp*)Me2(pmbd) in Acetone-d6 ..................................................46 2.5.7 Isolation and characterization of Pd(Tp*)Me3 (2.2) .................................................48 2.5.8 X-ray structure determination of Pd(Tp*)Me3 ..........................................................50 2.6 References for Chapter 2 ...................................................................................................52 Chapter 3 - Facile Transformations of hydridotris(3,5-dimethylpyrazolyl)borate – An Intramolecular Frustrated Lewis Pair.............................................................................................55 3.1 Abstract ..............................................................................................................................55 3.2 Introduction ........................................................................................................................55 3.3 Results and Discussion ......................................................................................................59 3.4 Conclusions ........................................................................................................................64 3.5 Experimental Section .........................................................................................................65 3.5.1 General Specifications ...........................................................................................65 3.5.2 Synthesis of the acetone adduct of tris(3,5-dimethylpyrazol-1-yl)borane (Compound 3.1) .....................................................................................................65 3.5.3 Synthesis of the bis-acetone adduct of bis(3,5-dimethylpyrazol-1-yl)borinium (Compound 3.2) .....................................................................................................67 3.5.4 Complexation of ZnBr2 with 3.1 ............................................................................69 3.6 References for Chapter 3 ...................................................................................................69 Chapter 4 - Synthesis and Characterization of 1- and 2-Adamantyl Anions .................................70 4.1 Abstract ..............................................................................................................................70 4.2 Introduction ........................................................................................................................70 4.3 Results and Discussion ......................................................................................................74
Load more

Recommended publications
  • Synthesis and Photoelectrochemical Characterization of Tantalum Oxide Nanoparticles and Their Nitrogen Derivatives
    University of Nevada, Reno Synthesis and Photoelectrochemical Characterization of Tantalum Oxide Nanoparticles and their Nitrogen Derivatives A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemical engineering by Vijay Khanal Dr. Vaidyanathan (Ravi) Subramanian – Advisor August 2019 The Graduate School We recommend that the dissertation prepared under our supervision by VIJAY KHANAL Entitled Synthesis and Photoelectrochemical Characterization of Tantalum Oxide Nanoparticles and their nitrogen Derivatives Be accepted in partial fulfillment of the Requirements for the degree of DOCTOR OF PHILOSOPHY Vaidyanathan (Ravi) Subramanian, Ph.D., Advisor Dhanesh Chandra, Ph.D., Committee Member Alan Fuchs, Ph.D., Committee Member Victor Vasquez, Ph.D., Committee Member Mario A. Alpuche, Ph.D. Graduate School Representative David W. Zeh, Ph.D., Dean, Graduate School August 2019 i ABSTRACT This work presents a surfactant-mediated approach for the synthesis of Ta2O5 nanopar- 2 1 2 1 ticles with a very high surface area (41 m g− vs. 1.6 m g− for commercial equivalent), and their subsequent nitridation to yield two distinct nitrogen derivatives: TaON and Ta3N5. Excellent photocatalytic efficiency of Ta2O5 toward photodegradation of methy- lene blue and NOx removal is reported. Ta3N5 shows significant photoconversion of methylene blue attributable to its lowered bandgap and high adsorption capability of MB molecules on its surface. A new method for simplifying the existing synthesis protocols of single phase Tantalum oxynitride (TaON) was devised. Series of photoelectrochemical characterization shows that the newly synthesized TaON can significantly enhance the photoassisted charge generation, separation, and transportation compared to the parent oxide (Ta2O5).
    [Show full text]
  • This Thesis Has Been Submitted in Fulfilment of the Requirements for a Postgraduate Degree (E.G
    This thesis has been submitted in fulfilment of the requirements for a postgraduate degree (e.g. PhD, MPhil, DClinPsychol) at the University of Edinburgh. Please note the following terms and conditions of use: This work is protected by copyright and other intellectual property rights, which are retained by the thesis author, unless otherwise stated. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the author. The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the author. When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given. Development of a High Temperature Sensor Suitable for Post-Processed Integration with Electronics Aleksandr Tabasnikov A thesis submitted for the degree of Doctor of Philosophy The University of Edinburgh 2016 Declaration of originality I declare that this thesis has been composed by me, the work is my own, and it has not been submitted for any other degree or professional qualification. Research recorded was carried out by me except as specified below: X-ray diffraction measurement results obtained using X-ray diffractometer Siemens D5000 were collected by Richard Yongqing Fu and his students Jimmy Zhou and Chao Zhao at the University of West of Scotland. Measurement results are analysed in section 4.4.6 of Chapter 4 and have been jointly published in 2014 (DOIs: 10.1109/ICMTS.2014.6841491).
    [Show full text]
  • Surface Modification of G-C3N4 by Hydrazine: Simple Way for Noble-Metal Free Hydrogen Evolution Catalysts
    Surface modification of g-C3N4 by hydrazine: Simple way for noble-metal free hydrogen evolution catalysts Item Type Article Authors Chen, Yin; Lin, Bin; Wang, Hong; Yang, Yong; Zhu, Haibo; Yu, Weili; Basset, Jean-Marie Citation Surface modification of g-C3N4 by hydrazine: Simple way for noble-metal free hydrogen evolution catalysts 2015 Chemical Engineering Journal Eprint version Post-print DOI 10.1016/j.cej.2015.10.080 Publisher Elsevier BV Journal Chemical Engineering Journal Rights NOTICE: this is the author’s version of a work that was accepted for publication in Chemical Engineering Journal. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Chemical Engineering Journal, 2 November 2015. DOI: 10.1016/ j.cej.2015.10.080 Download date 03/10/2021 23:51:44 Link to Item http://hdl.handle.net/10754/581797 Accepted Manuscript Surface modification of g-C3N4 by hydrazine: Simple way for noble-metal free hydrogen evolution catalysts Yin Chen, Bin Lin, Hong Wang, Yong Yang, Haibo Zhu, Weili Yu, Jean-marie Basset PII: S1385-8947(15)01491-6 DOI: http://dx.doi.org/10.1016/j.cej.2015.10.080 Reference: CEJ 14356 To appear in: Chemical Engineering Journal Received Date: 18 June 2015 Revised Date: 9 October 2015 Accepted Date: 26 October 2015 Please cite this article as: Y. Chen, B. Lin, H. Wang, Y.
    [Show full text]
  • Tantalum Nitride Nanotube Photoanodes: Establishing a Beneficial Back-Contact by Lift-Off and Transfer to Titanium Nitride Layer
    Tantalum nitride nanotube photoanodes: establishing a beneficial back-contact by lift-off and transfer to titanium nitride layer Lei Wang, a Anca Mazare, a Imgon Hwang, a and Patrik Schmuki a,b,* a Department of Materials Science and Engineering, WW4-LKO, University of Erlangen- Nuremburg, Martensstrasse 7, D-91058 Erlangen, Germany. b Department of Chemistry, King Abdulaziz University, Jeddah, Saudi Arabia * E-mail: [email protected] Abstract In this work we introduce the use of TiN/Ti2 N layers as a back contact for lifted-off membranes of anodic Ta3N5 nanotube layers. In photoelectrochemical H2 generation experiments under simulated AM 1.5G light, shift of the onset potential for anodic photocurrents to lower potentials is observed, as well as a higher magnitude of the photocurrents compared to conventional Ta3N5 nanotubes (~0.5 V RHE ). We ascribe this beneficial effect to the improved conductive properties of the TiNx -based back contact layer that enables a facilitated electron-transport for tantalum-nitride based materials to the conductive substrate. Key words: tantalum nitride; nanotube membranes; titanium nitride; water splitting Link to the published article: http://dx.doi.org/10.1016/j.elecom.2016.08.012 1. Introduction Ta3N5 is considered to be one of the most important semiconductor materials for photoelectrochemical (PEC) water splitting. It has a visible-light active band gap of ~2.1 eV that embraces the H2O H2/O2 reduction-oxidation potentials, and thus may yield a 15.9% theoretical maximum solar-to-hydrogen (STH) conversion efficiency [1-9]. Extensive research has focused on nanostructuring the Ta3N5 photoelectrodes, in the form of nanoparticles, nanorods, or nanotubes [10-15].
    [Show full text]
  • Tanねlum Penねchlorid』E with Ammo血血the Vapor Pkase An《量properties of the Tan．Tal㎜ N’Itride Forme通
    676 DENKI KAGAKU Fomation Process of Tanね1㎜Nitri－e by the Reaction of Tanねlum Penねchlorid』e with Ammo血血the VaPor Pkase an《量Properties of the Tan．tal㎜ N’itride Forme通 Akimasa YAJIMA＊，Ryoko MATsuzAKI＊and Yuzo SAEKI＊ The reaction products of gaseous TaC15with ammonia were TaCl5・5NH3at2QO。CラTaC15・5 NH3，Ta3N5，NH4Cl at250～600℃，Ta3N5and NH4Cl at650～950。C，Ta3N5，Ta4N5・and NH4Cl at 10000C，and Ta4N5シTa2N，θ一TaN，ε一TaN，NH4Cl，and HCl at1100～1400。C．In the vapor、phase reaction of gaseous TaCl5with ammonia，the reaction of gaseous TaC15with ammonia to form TaCI5・5NH3㏄curs丘rst．Above6α．235。C，the TaC15・5NH3reacts with ammonia to form Ta3N5． Above侃．1000。C，the Ta3N5decomposes to Ta4N5．Above侃。1100。C，in addition to these reactiolls， the nitriding of tantalum，formed by the reduction of gaseous TaCI5with hydrogen resulting from the thermal dissociation of ammonia，also o㏄urs to form Ta2Nシθ一TaN，andε一TaN．On heating the Ta3N5，formed by the vapor－phase reaction，in an argon atmosphere，it changed to Ta4N5at6α・ 9000C，to Ta5N6，θ一TaN，andε一TaN at6α．1100。C，and then toθ一TaN andε一TaN at1300～1400。C． The tantalum nitrides formed above1200。C were uniform，ultra丘ne powders with the particle diametersoftheorderof1／100粋m． 11ntroduction 2 Experimental The vapor－phase reaction of transition metal 2．1Materials chlorides with ammonia has recently become The TaCl，used was prepared by the reaction important for the preparation of6ne powders of tantalum powder（Ta99．8形，Hermann C． or thin丘lms of transition metal nitrides，which Starck Berlin）with chlorine at350℃and puri一 are aquiring importance
    [Show full text]
  • Nonaqueous Syntheses of Metal Oxide and Metal Nitride Nanoparticles
    Max-Planck Institut für Kolloid and Grenzflächenforschung Nonaqueous Syntheses of Metal Oxide and Metal Nitride Nanoparticles Dissertation zur Erlangung des akademischen Grades “doctor rerum naturalium” (Dr. rer. nat.) in der Wissenschaftsdisziplin “Kolloidchemie” eingereicht an der Mathematisch-Naturwissenschaftlichen Fakultät Universität Potsdam von Jelena Buha Potsdam, im Januar 2008 Dieses Werk ist unter einem Creative Commons Lizenzvertrag lizenziert: Namensnennung - Keine kommerzielle Nutzung - Weitergabe unter gleichen Bedingungen 2.0 Deutschland Um die Lizenz anzusehen, gehen Sie bitte zu: http://creativecommons.org/licenses/by-nc-sa/2.0/de/ Elektronisch veröffentlicht auf dem Publikationsserver der Universität Potsdam: http://opus.kobv.de/ubp/volltexte/2008/1836/ urn:nbn:de:kobv:517-opus-18368 [http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18368] С’ вером у Богa Abstract Nanostructured materials are materials consisting of nanoparticulate building blocks on the scale of nanometers (i.e. 10-9 m). Composition, crystallinity and morphology can enhance or even induce new properties of the materials, which are desirable for todays and future technological applications. In this work, we have shown new strategies to synthesise metal oxide and metal nitride nanomaterials. The first part of the work deals with the study of nonaqueous synthesis of metal oxide nanoparticles. We succeeded in the synthesis of In2O3 nanopartcles where we could clearly influence the morphology by varying the type of the precursors and the solvents; of ZnO mesocrystals by using acetonitrile as a solvent; of transition metal oxides (Nb2O5, Ta2O5 and HfO2) that are particularly hard to obtain on the nanoscale and other technologically important materials. Solvothermal synthesis however is not restricted to formation of oxide materials only.
    [Show full text]
  • (12) United States Patent (10) Patent No.: US 6,436,268 B1 Melody Et Al
    USOO6436268B1 (12) United States Patent (10) Patent No.: US 6,436,268 B1 Melody et al. (45) Date of Patent: Aug. 20, 2002 (54) NON-AQUEOUSELECTROLYTES FOR 5,587,871. A 12/1996 Ue et al. ANODIZING 5,605,561 A 2/1997 Iwabuchi et al. 5,670,741. A * 9/1997 Stromcuist et al. ...... 149/109.6 (75) Inventors: Brian John Melody; John Tony 5,687,057. A 11/1997 Dapo Kinard, both of Greer; David 5,716,511 A 2/1998 Melody et al. Alexander Wheeler, Williamston; 6,051,044. A 4/2000 Fife Philip Michael Lessner, Simpsonville, FOREIGN PATENT DOCUMENTS all of SC (US) EP O569 121 11/1993 GB 537474 6/1941 (73) Assignee: Kemet Electronics Corporation, GB 2168383 6/1986 Greenville, SC (US) WO WO98/19811 5/1998 Notice: Subject to any disclaimer, the term of this OTHER PUBLICATIONS patent is extended or adjusted under 35 Jackson N.F. et al., Institute of Electrical Engineers Steve U.S.C. 154(b) by 77 days. nage, GB, “The use of niobium as an anode material in liquid filled electrolytic capacitors', Database accession No. (21) Appl. No.: 09/630,605 733083 XP002144913 Abstract & Electrocomponent Sci (22) Filed: Aug. 2, 2000 ence and Technology, Sep. 1974, UK vol. 1, No. 1, pp. 27 37. (51) Int. Cl................................................. C25D 11/02 Patent Abstracts of Japan, vol. 10, No. 373, Abs Grp No.: (52) U.S. Cl. ........................ 205/234; 205/322; 205/332 C391, Abstracting Applin. No. 60–8438, Dec. 1986. (58) Field of Search ................................. 205/234, 322, Melody et al., An Improved Series of Electrolytes For Use 205/332 In The Anodization of Tantalum Capacitor Anodes, Pre Sented at the Capacitor and Resistor Technology Symposium (56) References Cited (C.A.R.TX.
    [Show full text]
  • Deposition and Characterization of Magnetron Sputtered Bcc Tantalum
    Copyright Warning & Restrictions The copyright law of the United States (Title 17, United States Code) governs the making of photocopies or other reproductions of copyrighted material. Under certain conditions specified in the law, libraries and archives are authorized to furnish a photocopy or other reproduction. One of these specified conditions is that the photocopy or reproduction is not to be “used for any purpose other than private study, scholarship, or research.” If a, user makes a request for, or later uses, a photocopy or reproduction for purposes in excess of “fair use” that user may be liable for copyright infringement, This institution reserves the right to refuse to accept a copying order if, in its judgment, fulfillment of the order would involve violation of copyright law. Please Note: The author retains the copyright while the New Jersey Institute of Technology reserves the right to distribute this thesis or dissertation Printing note: If you do not wish to print this page, then select “Pages from: first page # to: last page #” on the print dialog screen The Van Houten library has removed some of the personal information and all signatures from the approval page and biographical sketches of theses and dissertations in order to protect the identity of NJIT graduates and faculty. ABSTRACT DEPOSITION AND CHARACTERIZATION OF MAGNETRON SPUTTERED BCC TANTALUM by Anamika Patel The goal of this thesis was to provide scientific and technical research results for developing and characterizing tantalum (Ta) coatings on steel substrates deposited by DC magnetron sputtering. Deposition of tantalum on steel is of special interest for the protection it offers to surfaces, e.g.
    [Show full text]
  • Films Deposited with Different N2 Flow Rates
    coatings Article Study on the Electrical, Structural, Chemical and Optical Properties of PVD Ta(N) Films Deposited with Different N2 Flow Rates Yingying Hu 1, Md Rasadujjaman 1,2,* , Yanrong Wang 1, Jing Zhang 1, Jiang Yan 3,* and Mikhail R. Baklanov 1,4 1 Department of Microelectronics, North China University of Technology, Beijing 100144, China; [email protected] (Y.H.); [email protected] (Y.W.); [email protected] (J.Z.); [email protected] (M.R.B.) 2 Department of Physics, Dhaka University of Engineering & Technology, Gazipur 1707, Bangladesh 3 High-Tech Innovation Institute, North China University of Technology, Beijing 100144, China 4 Research and Education Center “Technological Center”, MIREA—Russian Technological University, 119454 Moscow, Russia * Correspondence: [email protected] (M.R.); [email protected] (J.Y.) Abstract: By reactive DC magnetron sputtering from a pure Ta target onto silicon substrates, Ta(N) films were prepared with different N2 flow rates of 0, 12, 17, 25, 38, and 58 sccm. The effects of N2 flow rate on the electrical properties, crystal structure, elemental composition, and optical properties of Ta(N) were studied. These properties were characterized by the four-probe method, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SE). Results show that the deposition rate decreases with an increase of N2 flows. Furthermore, as resistivity increases, the crystal size decreases, the crystal structure transitions from β-Ta to TaN(111), and finally becomes the N-rich phase Ta3N5(130, 040). Studying the optical properties, it is found that there are differences in the refractive index (n) and extinction coefficient (k) of Ta(N) with different thicknesses and Citation: Hu, Y.; Rasadujjaman, M.; different N2 flow rates, depending on the crystal size and crystal phase structure.
    [Show full text]
  • CHARACTERIZATION of TANTALUM NITRIDE THIN FILMS SYNTHESIZED by MAGNETRON SPUTTERING by ANNA ZAMAN Presented to the Faculty of T
    CHARACTERIZATION OF TANTALUM NITRIDE THIN FILMS SYNTHESIZED BY MAGNETRON SPUTTERING by ANNA ZAMAN Presented to the Faculty of the Graduate School of The University of Texas at Arlington in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE IN MATERIALS SCIENCE AND ENGINEERING THE UNIVERSITY OF TEXAS AT ARLINGTON May 2014 Copyright © by Anna Zaman 2014 All Rights Reserved ii Acknowledgements I would like to thank Dr. Efstathios I. Meletis, for his guidance, instructions and encouragement throughout the research work. I would like to thank Dr. Jiang for further advising me on this project. I would like to thank Dr. Tibbals and Dr. Jiang for serving on my committee. I’d like to acknowledge the UTA labs SaNEL and CCMB, because of which the research was possible. I would like to acknowledge my group members for their support. I would specially like to thank Jessica Mooney for training me and guiding me with this project. I would like to thank Adam Smith and Mingui Zhang for their assistance with the Nano-Indenter. Finally, I would like to thank my family for their cooperation and support throughout my studies. April 7, 2014 iii Abstract CHARACTERIZATION OF TANTALUM NITRIDE THIN FILMS SYNTHEISZED BY MAGNETRON SPUTTERING Anna Zaman, M.S. The University of Texas at Arlington, 2014 Supervising Professor: Efstathios I. Meletis Tantalum Nitride is chemically inert, oxidation resistant and hard. TaN finds applications as a protective coating due to its excellent wear properties. It has become a very promising diffusion barrier material in Cu interconnect technology in microelectronics. TaN has not been analyzed as much as other transition metal nitrides like the TiN system because TaN exhibits various stable and metastable phases.
    [Show full text]
  • Nitridation in the Processing and Preparation of Metals and Ceramics
    Nitridation in the Processing and Preparation of Metals and Ceramics O. Addemir, A. Tekin and C.K. Gupta* Faculty of Chemistry and Metallurgy, Istanbul Technical University, 80286 Maslak, Istanbul, Turkey; *Materials Group, Bhabha Atomic Research Centre, Bombay 400 085, India ABSTRACT 1. INTRODUCTION The formation and separation of metal nitrides from Most of the elements in the periodic table combine a variety of materials including ferroalloys, oxides, with nitrogen to form nitrogen compounds or nitrides. natural materials and minerals is an important com- Based on their structure and bonding characteristics, ponent in current materials processing practice. they have been divided into four groups and among Ferroalloys like ferroniobium and ferrovanadium these the transition metal nitrides and the diamond-like undergo nitridation by ammonia yielding a mixture of nitrides exhibit more readily usable properties. Among iron nitrides and the refractory metal nitride. Acid the many properties of the nitrides, the high melting leaching effectively separates the iron nitride from the point, high hardness and resistance to corrosion are mixture. Niobium nitride thus obtained is used to very attractive. However, nitrides are also brittle, produce niobium metal by pyrovacuum treatment. readily oxidise at high temperatures and many of them Vanadium nitride converts to metal when pyrovacuum thermally decompose. While some of these limitations treatment is followed by electrorefining. Nitride have been partially overcome in novel compositions suitable for decomposition to metal can be obtained like sialon, the extensive use of the majority of nitrides from niobium pentoxide by reacting ammonia or by is restricted by these limitations. In recent times, the reacting a mixture of carbon and nitrogen.
    [Show full text]
  • Ammonothermal Synthesis of Functional Ternary and Multinary
    Dissertation zur Erlangung des Doktorgrades der Fakultät für Chemie und Pharmazie der Ludwig-Maximilians-Universität München Ammonothermal Synthesis of Functional Ternary and Multinary Nitrides Jonas Häusler aus Ingolstadt, Deutschland 2018 Erklärung Diese Dissertation wurde im Sinne von § 7 der Promotionsordnung vom 28. November 2011 von Herrn Prof. Dr. Wolfgang Schnick betreut. Eidesstattliche Versicherung Diese Dissertation wurde eigenständig und ohne unerlaubte Hilfe erarbeitet. München, den 24.04.2018 .................................... (Jonas Häusler) Dissertation eingereicht am 01.03.2018 1. Gutachter Prof. Dr. W. Schnick 2. Gutachter Prof. Dr. R. Niewa Mündliche Prüfung am 17.04.2018 Acknowledgements Acknowledgements Ich möchte mich herzlich bei Herrn Prof. Dr. Schnick für die Möglichkeit bedanken, meine Dissertation in seinem Arbeitskreis anfertigen zu können. Die hervorragenden Arbeitsbedingungen und die Freiheiten bei der Umsetzung neuer Ideen waren perfekte Voraussetzungen für die eigenständige Gestaltung meiner Promotion. Die Bearbeitung eines neuen Themenbereichs in der Arbeitsgruppe stellte außerdem eine besonders spannende und zugleich abwechslungsreiche Herausforderung dar. Ich möchte mich darüber hinaus für die zahlreichen positiven Anregungen und Gespräche bedanken und für die vielen Gelegenheiten, an Fachtagungen sowie an der ersten Summerschool für ammonothermale Kristallzucht in Erlangen und Santa Barbara teilnehmen zu können. Ganz besonderer Dank gilt zudem Herrn Prof. Dr. Rainer Niewa für Übernahme des Koreferats meiner Dissertation sowie für die tolle Zusammenarbeit in unserer Forschergruppe und die große Hilfsbereitschaft bei jeglichen Diskussionen und Fragestellungen. Herrn Prof. Dr. Wolfgang Beck, Herrn Prof. Dr. Hans-Christian Böttcher, Herrn Prof. Dr. Konstantin Karaghiosoff und Herrn Prof. Dr. Joost Wintterlin danke ich herzlich für ihre Bereitschaft, als Teil der Prüfungskommission meiner Doktorarbeit zur Verfügung zu stehen.
    [Show full text]