DOCSLIB.ORG

Metalation Studies on Titanocene Dithiolates

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Metalation Studies on Titanocene Dithiolates inorganics Article Metalation Studies on Titanocene Dithiolates Tilmann G. Kießling and Karlheinz Sünkel * ID Department of Chemistry, Ludwig-Maximilians University Munich, 81377 Munich, Germany; [email protected] * Correspondence: [email protected]; Tel.: +49-89-2180-77773 Received: 18 July 2018; Accepted: 22 August 2018; Published: 24 August 2018 Abstract: Titanocene bis-arylthiolates [(C5H4X)(C5H4Y)Ti(SC6H4R)2] (X,Y = H, Cl; R = H, Me) can be prepared from the corresponding titanocene dichlorides by reacting with the thiols in the presence of DABCO as a base. They react with n-butyl lithium to give unstable Ti(III) radical anions. While the unsubstituted thiolates (X = Y = R = H) react with lithium Di-isopropylamide by decomposing to dimeric fulvalene-bridged and thiolate-bridged Ti(III) compounds, the ring-chlorinated compounds can be deprotonated with LDA and give appropriate electrophiles di-substituted and tri-substituted titanocene dithiolates. Keywords: titanocene thiolates; metalation; chlorocyclopentadienyl ligands 1. Introduction Titanocene compounds, i.e., compounds of the type “Cp2TiXn” where “Cp” stands for a substituted or unsubstituted cyclopentadienyl ligand and “X” for any anionic or neutral ligand and n = 0–2 are arguably the second-most studied metallocenes after ferrocene. Soon after the first synthesis of (C5H5)2TiCl2 in 1954 [1], its potential for acting as a polymerization catalyst when combined with certain aluminum compounds was discovered [2]. Further studies showed that a judicious choice of substituents on the cyclopentadienyl ring had a great influence on the stereochemistry of the produced polymers, which gave rise to an enormous number of publications and also many review articles [3–8]. However, it was also found that the titanium catalysts were rather quickly deactivated and the corresponding zirconium compounds showed much higher stability and catalytic activity. Thus, the mainstream research on metallocene catalysts stopped for titanium-based metallocenes nearly completely until recently when the concepts of “Green Chemistry” and “Sustainable Catalysis” came into play [9–12]. Another area of “applied research” opened up after the discovery that Cp2TiCl2 showed antitumor activity [13–15]. Here again, it turned out that the effectiveness of the titanocenes could be enhanced by introducing substituents on the cyclopentadienyl rings [16,17] as well as by modifying the “X”-ligands [17,18]. Lastly, titanocenes were the subject of purely “academic” studies, e.g. studies devoted to synthesis, isolation, and characterization of the “true” titanocenes “Cp2Ti” [19] or of “chiral at titanium” complexes “CpCp’TiXY” [20]. In addition, in these studies, the importance of cyclopentadienyl ring substituents was well established. All of the titanocenes with substituted cyclopentadienyl rings known so-far have been prepared by a reaction of the substituted cyclopentadiene with TiCln (n = 2–4). This method fails for very electronegative substituents or substituents with ligating properties. Since our group focuses on the synthesis of Cyclopentadienyl complexes with such substituents for a long time, using an approach of performing halogen-metal exchange reactions followed by electrophilic substitutions on already coordinated perhalogenated cyclopentadienyl ligands [21], we wondered if our approach was also suitable for the titanocene system. Since our synthetic protocol always involves the use of lithium organyls or lithium amides, there was also the need for a proper titanocene starting material. It has been known for a long time that titanocene Inorganics 2018, 6, 85; doi:10.3390/inorganics6030085 www.mdpi.com/journal/inorganics Inorganics 2018, 6, 85 2 of 12 chloridesInorganics react 2018, with6, x FOR alkyl PEER lithiumsREVIEW to thermally unstable titanocene alkyls Cp2TiR2, which2 of 12 easily decompose to titanium(III) products [22,23] and with lithium amides to mono-cyclopentadienyl alkyl lithiums to thermally unstable titanocene alkyls Cp2TiR2, which easily decomposet to titanium tris-amides CpTi(NR2)3 [24]. In addition, with the often-used base KO Bu, a mixture of titanium(III) products [22,23] and with lithium amides to mono-cyclopentadienyl titanium products including those of splitting off the cyclopentadienyl ligands was observed [25]. We, therefore, tris-amides CpTi(NR2)3 [24]. In addition, with the often-used base KOtBu, a mixture of products decided to look at the also long-known titanocene thiolates Cp Ti(SR) . These compounds are usually including those of splitting off the cyclopentadienyl ligands2 was observed2 [25]. We, therefore, prepared either by a reaction of Cp TiCl with thiols in the presence of the base, which were sometimes decided to look at the also lo2ng-known2 titanocene thiolates Cp2Ti(SR)2. These compounds are contaminatedusually prepared with theeither mixed by a reaction chloride-thiolates of Cp2TiCl2 with Cp2 thiolsTi(SR)Cl in the [26 presence–28] or of by the oxidative base, which addition were of disulfidessometimes to in-situ contaminated prepared with “Cp the2Ti” mixed [29]. chloride-thiolates Some of these thiolatesCp2Ti(SR)Cl showed [26–28] promising or by oxidative antitumor propertiesaddition [30 of,31 disulfides]. to in-situ prepared “Cp2Ti” [29]. Some of these thiolates showed promising antitumorIn this study, properties we report [30,31]. on the synthesis of several titanocene bis(aryl thiolates) (Cp)(Cp’)Ti(SAr)2 and theirIn reactivitythis study, towards we report lithium on the alkyls synthesis and amidesof several including titanocene functionalization bis(aryl thiolates) of the cyclopentadienyl(Cp)(Cp’)Ti(SAr) rings.2 and It their should reactivity be mentioned towards lithium here that alkyls a related and amides approach including was used functionalization for deriving the so-calledof the “Troticenes” cyclopentadienyl CpTi(Cht) rings. [It32 should]. be mentioned here that a related approach was used for deriving the so-called “Troticenes” CpTi(Cht) [32]. 2. Results 2. Results 2.1. Synthesis of Starting Materials 2.1. Synthesis of Starting Materials Treatment of the known titanocene dichlorides (C5H4X)(C5H4Y)TiCl2 (X = Y = H, 1a; Treatment of the known titanocene dichlorides (C5H4X)(C5H4Y)TiCl2 (X = Y = H, 1a; X = H, Y = X = H, Y = Cl, 1b; X = Y = Cl, 1c)[33,34] with HS–C H R (R = H, p-Me) in the Cl, 1b; X = Y = Cl, 1c) [33,34] with HS–C6H4R (R = H, p-Me) 6in 4the presence of DABCO presence(1,4-diazabicyclo[2.2.2]octane) of DABCO (1,4-diazabicyclo[2.2.2]octane) yields the yieldscorresponding the corresponding titanocene titanocene arylthiolates arylthiolates (C5H(C4X)(C5H4X)(C5H45Y)Ti(S–CH4Y)Ti(S–C6H6H4R)4R)2 2(R (R == H, 2a–c,, Me: Me: 3a–c3a–c), ),respectively, respectively, in ingood good yields yields (64% (64% to 89% to89% except except for 3bfor, 19%) 3b, 19%) (Scheme (Scheme1). 1). SchemeScheme 1. 1.Synthesis Synthesis ofof substitutedsubstituted titanocene titanocene thiolates. thiolates. Compounds 2a and 3a had been reported before [26,27]. All compounds were characterized by 1CompoundsH-NMR and 132aC-NMRand 3a andhad mass been spectroscopy reported beforeincluding [26 ,HRMS.27]. All The compounds NMR spectra were of 3b/c characterized show the by 1 13 H-NMRpresence and of C-NMRHS–C6H4 andCH3 massor [S–C spectroscopy6H4–CH3]2 and including very weak HRMS. signals The (<2%) NMR derived spectra from of 3b/c 1b/cshow and the presence(C5H4 ofX)(C HS–C5H4Y)Ti(S–C6H4CH63Hor4R)Cl. [S–C 6H4–CH3]2 and very weak signals (<2%) derived from 1b/c and (C5H4X)(C5H4Y)Ti(S–C6H4R)Cl. 2.2. Reaction of Dithiolates 2a and 3a with Butyllithium 2.2. ReactionTreatment of Dithiolates of a suspension2a and 3a ofwith 2a or Butyllithium 3a with 1.1 equivalents of n-BuLi in THF at −78 °C results in theTreatment formation of aof suspension yellow solutions. of 2a or Warming3a with to 1.1 ro equivalentsom temperature of n-BuLi leads into THFa color at −change78 ◦C resultsfrom in the formationyellow to ofbrown yellow within solutions. five minutes. Warming The to resulting room temperature solutions appear leads to to be a colorparamagnetic change fromsince yellowit turns out impossible to obtain any good-quality 1H- or 13C-NMR spectra. However, the solutions to brown within five minutes. The resulting solutions appear to be paramagnetic since it turns out resulting from 2a show a 7Li-NMR resonance at δ = 2.64 ppm while the solutions resulting from 3a impossible to obtain any good-quality 1H- or 13C-NMR spectra. However, the solutions resulting exhibit a 7Li-NMR signal at δ = 2.74 ppm (Figures S5 and S6). For comparison, the 7Li-NMR signals of from 2a show a 7Li-NMR resonance at δ = 2.64 ppm while the solutions resulting from 3a exhibit a 7Li-NMR signal at δ = 2.74 ppm (Figures S5 and S6). For comparison, the 7Li-NMR signals of THF Inorganics 2018, 6, 85 3 of 12 solutionsInorganics of 2018 Li(C, 65, xH FOR5), PEER LiSC REVIEW6H5, and LiSC6H4CH3 can be found at δ = −8.37, 1.98, and3 1.90 of 12 ppm, respectively). Cooling these solutions down to −78 ◦C leads to a color change and it turns into a violet color.THF Warming solutions up of to Li(C room5H5), temperature LiSC6H5, and reinstatesLiSC6H4CH the3 can brown be found color at δ and = −8.37, evaporation 1.98, and 1.90 of the ppm, solvent respectively). Cooling these solutions down to −78 °C leads to a color change and it turns into a in vacuum leaves a brown residue, 2a0 or 3a0, respectively. When a frozen solution made up from 3a violet color. Warming up to room temperature reinstates the brown color and evaporation of the and four equivalents of butyl lithium in THF is gradually warmed up within a NMR spectrometer, solvent in vacuum leaves a brown residue, 2a′ or 3a′, respectively. When a frozen solution made up 1 ◦ a H-NMRfrom 3a spectrum and four immediately equivalents of taken butyl at lithium−80 C in shows THF nois gradually signals of warmed the Li–CH up 2withinprotons.
Load more

Recommended publications
  • Downloaded for Personal Non-Commercial Research Or Study, Without Prior Permission Or Charge
    Guthrie, Emma Jayne (2001) Novel routes to benzofurans using titanium- alkylidene chemistry. PhD thesis. http://theses.gla.ac.uk/3476/ Copyright and moral rights for this thesis are retained by the author 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 Glasgow Theses Service http://theses.gla.ac.uk/ [email protected] Novel Routes to Benzofurans using Titanium-Alkylidene Chemistry A Thesis submitted in part fulfilment of the requirements of the degree of Doctor of Philosophy Emma Jayne Guthrie Department of Chemistry University of Glasgow Glasgow G12 8QQ July 2001 tt © 2001 Emma Guthrie Dedicated to my family Acknowledgements I am grateful to the EPSRC and Aventis cropsciencefor financial support in this work. Technical support was gratefully received from Mrs Kim Wilson (microanalysis), Mr Tony Ritchie (massspectroscopy) and Mr Jim Gall and Dr David Rycroft (NMR). Also thanks to Mrs Isabel Freer for keeping the Henderson Lab organised. Thanks also to Mr Gordon McKiernan for his purification of compound 181. Particular thanks to Dr Richard Hartley for being an inspiring supervisor, and providing continuous enthusiasm through my PhD. Thanks also to Dr Mary O'Mahoney and particularly to Dr Jackie Macritchie for supervisory support from Aventis.
    [Show full text]
  • Pentamethylcyclopentadienyl Aminoborole Complexes of Hafnium
    Pentamethylcyclopentadienyl Aminoborole Complexes of Hafnium Thesis by Andrew F. Kiely In Partial Fufillment of the Requirements for the Degree of Doctor of Philosophy Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena, California 1997 (Submitted August 20,1996) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. For M y Parents Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. iii Acknowledgments First and most importantly, I would like to thank John Bercaw for the support, encouragement, and opportunities that he has given me over the course of my studies at Caltech. I have been very fortunate to have been able to learn chemistry from someone who is a fine and generous person as well as a great scientist, and I am very grateful to him. I am also grateful to Bill Schaefer, Larry Henling, and Mike Day for performing all the crystallographic work that is reported in this thesis. I appreciate all their good humor and patience despite my (occasional) impatience and (more occasional) ignorance. I've really enjoyed hiking with Bill and playing outfield with Larry as well. The students and post-docs in the Bercaw group have been friends as well as coworkers. Over the years, people in the Bercaw group have been generous with their time, advice and friendship. When I was getting started in the group, Donny Cotter, Bryan Coughlin, and Roger Quan were never too busy to answer my questions or to set me straight. I'm especially grateful to Roger, who helped me to learn vacuum line techniques when I was starting on the aminoborole project.
    [Show full text]
  • A Novel Series of Titanocene Dichloride Derivatives: Synthesis, Characterization and Assessment of Their
    A novel series of titanocene dichloride derivatives: synthesis, characterization and assessment of their cytotoxic properties by Gregory David Potter A thesis submitted to the Department of Chemistry in conformity with the requirements for the degree of Doctor of Philosophy Queen’s University Kingston, Ontario, Canada May, 2008 Copyright © Gregory David Potter, 2008 Abstract Although cis-PtCl2(NH3)2 (cisplatin) has been widely used as a chemotherapeutic agent, its use can be accompanied by toxic side effects and the development of drug resistance. Consequently, much research has been focused on the discovery of novel transition metal compounds which elicit elevated cytotoxicities coupled with reduced toxic side effects and non-cross resistance. Recently, research in this lab has focused on preparing derivatives of titanocene dichloride (TDC), a highly active chemotherapeutic agent, with pendant alkylammonium groups on one or both rings. Earlier results have demonstrated that derivatives containing either cyclic or chiral alkylammonium groups had increased cytotoxic activities. This research therefore investigated a new series of TDC complexes focusing specifically on derivatives bearing cyclic and chiral alkylammonium groups. A library of ten cyclic derivatives and six chiral derivatives were synthesized and fully characterized. These derivatives have undergone in vitro testing as anti-tumour agents using human lung, ovarian, and cervical carcinoma cell lines (A549, H209, H69, H69/CP, A2780, A2780/CP and HeLa). These standard cell lines represent solid tumour types for which new drugs are urgently needed. The potencies of all of the Ti (IV) derivatives varied greatly (range from 10.8 μM - >1000 μM), although some trends were observed. In general, the dicationic analogues exhibited greater potency than the corresponding monocationic derivatives.
    [Show full text]
  • Syntheses, Crystal Structures and Enantioseparation 2
    ansa-Metallocene derivatives XXXIX 1 Biphenyl-bridged metallocene complexes of titanium, zirconium, and vanadium: syntheses, crystal structures and enantioseparation 2 Monika E. Huttenloch, Birgit Dorer, Ursula Rief, Marc-Heinrich Prosenc, Katrin Schmidt, Hans H. Brintzinger * Fakultiitfiir Chemie. UniL'ersitiit KOl1stanz. Each M737. D-78457 Konstanz. Germany Abstract Chiral, biphenyl-bridged metallocene complexes of general type biph(3,4-R2CsH2)2MCI2 (biph = 1,1'-biphenyldiyI) were synthesized and characterized. For the dimethyl-substituted titanocenes and zirconocenes (R CH 3; M Ti, Zr). preparations with increafed overall yields and an optical resolution method were developed. The bis(2-tetrahydroindenyI) complexes (R,R = (CH2)4; M = Ti, Zr) were obtained by an alternative synthetic route and characterized with regard to their crystal structures. Syntheses of the phenyl-substituted derivatives (R C 6 H 5; M Ti, Zr) and of a chiral, methyl-substituted vanadocene complex (R CH 3; M V) are also reported. Keywords: Titanium; Zirconium; Vanadium; Metallocene; Enantioseparation 1. Introduction Me2Si(2-SiMe14-IBuCsH)2-metallocenes of Y, Sc, Ti, and Zr [10]. Jordan and coworkers recently developed a Ever since meso and racemic ansa-titanocene iso­ powerful method for the syntheses of rac-C 2 H i l-inde­ mers were first characterized by Huttner and coworkers nyl)2 Zr(NMez)2 and rac-SiMe2(I -indenyI)2 Zr(NMe 2)2 [1], the formation of these diastereomers and their sepa­ in high yields, which is based on equilibration of rac ration has been a continuing challenge in metallocene and meso products by the amine eliminated in the chemistry (for a review see Ref.
    [Show full text]
  • Ep 1 072 606 A1
    Europäisches Patentamt (19) European Patent Office Office européen des brevets (11) EP 1 072 606 A1 (12) EUROPEAN PATENT APPLICATION published in accordance with Art. 158(3) EPC (43) Date of publication: (51) Int. Cl.7: C07F 17/00 31.01.2001 Bulletin 2001/05 (86) International application number: (21) Application number: 98913757.5 PCT/ES98/00094 (22) Date of filing: 15.04.1998 (87) International publication number: WO 99/52918 (21.10.1999 Gazette 1999/42) (84) Designated Contracting States: • SANCHO ROYO, José BE DE ES FR GB IT NL E-28003 Madrid (ES) • MENDEZ LLATAS, Luis (71) Applicant: REPSOL QUIMICA S.A. E-28935 Mostoles (ES) E-28046 Madrid (ES) (74) Representative: (72) Inventors: Del Santo Abril, Natividad • PARELLADA FERRER, M Dolores Oficina Garcia Cabrerizo, S.L., E-28820 Coslada (ES) Vitruvio, 23 • BARRIO CALLE, Juan Antonio 28006 Madrid (ES) E-28007 Madrid (ES) (54) PROCESS FOR PREPARING AROMATIC DERIVATIVES OF TITANOCENE (57) Procedure for the preparation of aromatic OR4 where R4 is an alkyl group of 1 to 4 carbon derivatives of titanocene, useful as catalysts for the atoms; at least one of the R1, R2 or R3 is hydrogen. polymerisation and hydrogenation of polymers, charac- The preparation is carried out by the reaction of the terised by the use of a Grignard reagent. This proce- titanocene dichloride with the corresponding Grig- dure allows to easily prepare compounds with the nard reagent. This method substantially enhances general formula : safety, reproducibility, yield and cost of that carried out via lithium compounds. where: L, which can be equal to or different one from the other, are cyclopentadiene, or pentamethylcy- clopentadiene; preferably at least one L is cyclopentadiene; R1, R2, R3, equal or different from one another, are selected from the group consisting of: hydrogen, alkyl group from 1 to 4 carbon atoms, EP 1 072 606 A1 Printed by Xerox (UK) Business Services 2.16.7 (HRS)/3.6 12EP 1 072 606 A1 Description yield and cost of the method which is carried out via lith- ium compounds.
    [Show full text]
  • Synthesis and Electrochemistry of Dimetallocene-Containing Titanocenyl (IV) Complexes E
    Chem cal ist si ry y & h P B f i o o p Erasmus, J Phys Chem Biophys 2014, 4:4 l h a Journal of Physical Chemistry & y n s r i DOI: 10.4172/2161-0398.1000152 u c o s J ISSN: 2161-0398 Biophysics ResearchResearch Article Article OpenOpen Access Access Synthesis and Electrochemistry of Dimetallocene-Containing Titanocenyl (IV) Complexes E. Erasmus* Department of Chemistry, University of the Free State, Bloemfontein, 9300, Republic of South Africa Abstract IV II A series of dimetallocenyl dicyclopentadienyl titanium (IV) complexes of the from [(C5H5)2Ti ((C5H4)M (C5H5))2] with M=Fe, Ru and Os were synthesized by treatment of dicyclopentadienyltitanium (IV) dichloride (titanocene dichloride) with the corresponding metallocenyllithium. The metallocenyllithium was obtained by treatment of the corresponding metallocene (ferrocene (Fc), ruthenocene (Rc) and osmocene (Oc)) with either t-buthyllithium or n-buthyllithium. The electrochemistry of the dimetallocenyl dicyclopentadienyl titanium (IV) complexes was studied by cyclic voltammetry, linear sweep voltammetry and Oster Young square wave voltammetry. The titanocenyl group showed quasi-reversible to irreversible electrochemistry with the peak anodic potential (Epc vs FcH/FcH+) of the titanocenyl group dependent c c c on the atomic electronegativity of the metallocenyl ligand (Fe ( Fe=1.64), Ru ( Ru=1.42), Os ( oeOs=1.52)). The metallocenyl groups (Fc, Rc and Oc) showed quasi-reversibility and the quasi-formal reduction potential, E01, was also dependent on atomic electronegativity of the metal of the metallocenyl ligand. Synopsis and pictogram for Table of contents M Ti M M = Fe, Ru and Os. Synopsis IV II A series of dimetallocenyl dicyclopentadienyl titanium(IV) complexes of the type [(C5H5)2Ti ((C5H4)M (C5H5))2] where M=Fe, Ru and Os were synthesized and characterized by spectroscopic and electrochemical methods.
    [Show full text]
  • Low-Temperature One-Step Solid-Phase Synthesis of Carbon-Encapsulated Tio2 Nanocrystals As Anode Materials for Lithium-Ion Batteries
    Ionics DOI 10.1007/s11581-017-2053-6 ORIGINAL PAPER Low-temperature one-step solid-phase synthesis of carbon-encapsulated TiO2 nanocrystals as anode materials for lithium-ion batteries Boyang Liu1 & Yingfeng Shao 2 & Xin Xiang1 & Jiayuan Ren1 & Wenge Li 3 Received: 14 September 2016 /Revised: 27 February 2017 /Accepted: 27 February 2017 # Springer-Verlag Berlin Heidelberg 2017 Abstract A simple and highly efficient method is developed for after oxidative dehydrogenation coating on the TiO2 in situ one-step preparation of carbon co-encapsulated anatase nanocrystals, resulting in the formation of core-shell structure. and rutile TiO2 nanocrystals (TiO2@C) with core-shell structure The TiO2 nanocrystals prepared by titanocene dichloride have for lithium-ion battery anode. The synthesis is depending on the an equiaxed morphology with a small diameter of 10–55 nm and solid-phase reaction of titanocene dichloride with ammonium the median size is 30.3 nm. Hundreds of TiO2 nanocrystals are persulfate in an autoclave at 200 °C for 30 min. The other three encapsulated together by the worm-like carbon shell, which is titanocene complexes including bis(cyclopentadienyl)dicarbonyl amorphous and about 20–30 nm in thickness. The content of titanium, cyclopentadienyltitanium trichloride, and TiO2 nanocrystals in the nanocomposite is about 31.1 wt.%. cyclopentadienyl(cycloheptatrienyl)titanium are used instead to This TiO2@C anode shows stable cyclability and retains a good comprehensively investigate the formation mechanism and to reversible capacity of 400 mAh g−1 after 100 cycles at a current improve the microstructure of the product. The huge heat gener- density of about 100 mA g−1, owing to the enhanced conductiv- ated during the explosive reaction cleaves the cyclopentadiene ity and protection of carbon shell.
    [Show full text]
  • First-Principles Simulations of the Interaction of Metal-Organic Molecules with a Surface and As Building Blocks for Nanodevices
    Universite´ de Strasbourg IPCMS: CNRS - UMR 7504 These` de Doctorat FIRST-PRINCIPLES SIMULATIONS OF THE INTERACTION OF METAL-ORGANIC MOLECULES WITH A SURFACE AND AS BUILDING BLOCKS FOR NANODEVICES par Burak Ozdamar¨ pr´esent´eeen vue d'obtenir le grade de Docteur de l'Universit´ede Strasbourg Sp´ecialit´e:Physique de la mati`erecondens´eeet des mat´eriaux Soutenue publiquement le 28/10/2016 `al'IPCMS devant le jury compos´ede: Prof. Dr. Roberto Marquardt UdS-LCQ Pr´esident Prof. Dr. J¨urg Hutter UZH-CMSZH Rapporteur Prof. Dr. Andres Saul AMU-CINaM Rapporteur Prof. Dr. Fabrizio Cleri UL1-IEMN Rapporteur Dr. S´ebastien Le Roux UdS-IPCMS Examinateur Prof. Dr. Mauro Boero UdS-IPCMS Directeur de th`ese Tired of lying in the sunshine staying home to watch the rain You are young and life is long and there is time to kill today And then one day you find ten years have got behind you No one told you when to run, you missed the starting gun. Roger Waters iii Abstract UNIVERSITE´ DE STRASBOURG Institut de Physique et Chimie des Mat´eriauxde Strasbourg Doctor of Philosophy FIRST-PRINCIPLES SIMULATIONS OF THE INTERACTION OF METAL-ORGANIC MOLECULES WITH A SURFACE AND AS BUILDING BLOCKS FOR NANODEVICES by Burak Ozdamar¨ The purpose of this study is to investigate the interaction of organometallic com- plexes with transition metals. This topic in question has a broad array of applica- tions in a number of domain; realization of nanojunctions for molecular nanoelec- tronics, biological imaging and nanocatalysis. Within this general framework, this PhD project aims to model the fundamental interactions of molecular building blocks at the atomic level in order to understand their role in the assembly and functionalization of nanostructures.
    [Show full text]
  • Early Transition Metal Metallocenes in Cancer Research
    27 Early Transition Metal Metallocenes in Cancer Research Cornelia Bauer Literature Seminar March 28, 1995 The accidental discovery of the anti tumor properties of cisplatin by Rosenberg in 1969 led to a broad search of cytotoxic inorganic compounds. Aside from some platinum metal complexes, a variety of main group and transition metal compounds display such ac­ tivity. One particularly promising group of compounds are based on early-transition-metal metallocene complexes, which are active against a wide range of experimental and human cancers but are less toxic than cisplatin. One of the most attractive features of those com­ pounds is their activity against certain types of colon cancers which seldom respond to drugs. One important question in cancer research is the mechanism of the growth inhibition of can­ cerous cells. An understanding of the mechanism of drug action is critical to the rational de­ sign and improvement of new agents [1,2,3,4,5]. Systematic in vitro and in vivo studies have focused on the manipulation of the activ­ ity of met.allocene(IV)- complexes by changing the metal ion, the substituents on the cyclo­ pentadienyl (Cp) rings, and varying the metal bound ligands (e.g., halides, carboxylates, thiolates). Ti, V, Nb and Mo have been found to be the most active metals. Any kind of substitution on the Cp rings reduces the drug efficiency and the metal bound ligands exert only a slight effect on the activity of the drug [2,5,6]. Ti v Key: M =maximum activity 12.i Nb Mo M =sporatic activity IHIIT Ta w 00 =no activity Core level Electron Energy Loss Spectroscopy (EELS) on tumor cells treated with ti­ tanocene dichloride, reveals accumulation of Ti in DNA-rich cell areas, thus indicating DNA and RNA to be the primary cellular targets of metallocenes [7].
    [Show full text]
  • Organotitanium Chemistry (Merchant, 2017)
    Baran Group Meeting Rohan Merchant Organotitanium Chemistry 08/04/2017 Ziegler Natta Catalysts First row transition metal Electron Configuration: [Ar]3d24s2 Common Oxidation States: +2, +3, +4 Highly oxophilic Highly resistant to corrosion Originally Ti-based catalysts used to prepare stereoregular polymers from propylene Highest strength-to-weight ratio of any metal One of the most important use of organotitanium complexes In unalloyed condition, titanium is as strong as Karl Ziegler and Giulio Natta awarded the Nobel Prize in chemistry in 1963 some steels Today, this class of catalysts has been expanded to include: 1. Solid supported Ti-based catalysts, often used in conjunction with organoaluminum cocatalysts (Kroll Process) 2. Metallocene catalysts, often of Ti, Zr, or Hf, and typically in conjuntion with MAO 250,000 tons per year of titanium made from TiCl4 3. Post-metallocene catalysts, various transition metals used with multidentate N and O based ligands, often use MAO Fun Facts about Titanium Worldwide production of polymers using these catalysts in 2010 >100 million tons British pastor William Gregor discovered titanium in 1791 This topic has not been covered in the interest of time. Named by German chemistry Martin Heinrich Klaproth after Titans of Greek mythology in 1795 See: "Polymer Chemistry" GM by D. Holte (2011) 9th most abundant element in the Earth's crust (0.63% of Earth's crust) 7th most abundant metal Common titanium complexes used in synthesis Pure sample isolated in 1910 by Matthew A. Hunter (Hunter Process) i
    [Show full text]
  • Of Dibenzo[Fl,C]
    Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1994 Titanocene/Dna Binding and the Synthesis and Characterization of Bridged Cyclopentadienes for the Preparation of Novel Titanocenes. Tamara Renee Schaller Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Schaller, Tamara Renee, "Titanocene/Dna Binding and the Synthesis and Characterization of Bridged Cyclopentadienes for the Preparation of Novel Titanocenes." (1994). LSU Historical Dissertations and Theses. 5754. https://digitalcommons.lsu.edu/gradschool_disstheses/5754 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps.
    [Show full text]
  • Formation from Chlorophenols 82
    FORMATION OF AROMATIC COMPOUNDS BY CYCLOPENTADIENE MOIETIES IN COMBUSTION PROCESSES A Thesis Presented to The Academic Faculty by Do Hyong Kim In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the School of Civil and Environmental Engineering Georgia Institute of Technology August 2005 FORMATION OF AROMATIC COMPOUNDS BY CYCLOPENTADIENE MOIETIES IN COMBUSTION PROCESSES Approved by: Dr. James A. Mulholland, Advisor Dr. Armistead G. Russell School of Civil and Environmental School of Civil and Environmental Engineering Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Michael H. Bergin Dr. C. David Sherrill School of Civil and Environmental School of Chemistry and Biochemistry Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Kurt D. Pennell School of Civil and Environmental Engineering Georgia Institute of Technology Date Approved: 06/29/2005 This dissertation is dedicated to my family ACKNOWLEDGEMENTS I would like to thank the following people for their help and support throughout my program at Georgia Tech. First of all, I would like to especially thank Dr. James. A. Mulholland, my advisor, for his endless and excellent guidance. Words cannot be good enough to express my gratitude toward him. It was always my pleasure to work and spend time with him during last seven years. My gratitude also goes to Drs. Ted Russell, Kurt D. Pennell, Michael H. Bergin and David Sherrill for their guidance, helpful comments and time spent serving on my thesis committee. I like to thank Dr. Guangxuan Zhu, our lab manager, who has fixed many a problem and given excellent advice on analytical techniques in the lab.
    [Show full text]