DOCSLIB.ORG

A MATRIX ISOLATION SPECTROSCOPIC INVESTIGATION of the REACTION PRODUCTS of TRANSITION METAL CENTRES with ETHENE and WATER By

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A MATRIX ISOLATION SPECTROSCOPIC INVESTIGATION of the REACTION PRODUCTS of TRANSITION METAL CENTRES with ETHENE and WATER By A MATRIX ISOLATION SPECTROSCOPIC INVESTIGATION OF THE REACTION PRODUCTS OF TRANSITION METAL CENTRES WITH ETHENE AND WATER by MATTHEW G. K. THOMPSON 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 November 2007 Copyright © Matthew Gary Karl Thompson, 2007 Abstract The reaction products of thermally generated atomic V with ethene and ethene isotopomers have been investigated by matrix isolation ultraviolet visible and Fourier transform infrared (FTIR) spectroscopy. When V is deposited into matrices of pure Ar, evidence for V and V2 are present in the UV-visible absorption spectra. Addition of trace amounts of ethene results in the elimination of absorptions due to V2 on deposition, likely due to the formation of … V (C2H4) van der Waals complexes on matrix condensation. Irradiation of matrices containing V and trace C2H4 in Ar, with light corresponding to atomic V electronic excitations, eliminates all UV-visible absorptions due to atomic V in the matrix. Infrared analysis of matrices containing V and C2H4 give evidence for a new product on deposition, consistent with a kinetically formed H-V-C2H3 isomer. Following further irradiation of the matrix, several new products of C-H bond insertion by the metal atom, including additional H-V-C2H3 conformational 2 isomers, and H2V(η -C2H2) products are observed in the infrared spectrum. Additionally, the formation of ethane is evident as a major product immediately following deposition of V + C2H4 + H2O in Ar. The formation of this product is consistent with alkene insertion into the V-H bond of an H-V-OH intermediate, followed by a photo-induced elimination to give C2H6. Under higher C2H4 concentrations, competitive ethane formation in which a sacrificial hydrogenation mechanism involving two ethene molecules is observed, analogous to the mechanism proposed to account for V + H2O + C2H4. Isotopic ii investigations aimed at confirming key aspects of the proposed mechanisms are also presented. Similar reactivity is observed for several metals, suggesting that this reaction is a generalized reaction, whenever transition metal hydrides are formed. The additional observation of ethene hydrogenation where the initiating hydride source is either water, or ethene, suggests that this reaction could also easily generalize to other initiating hydride sources. The mechanism could also extend to the insertion of other π-bond containing species, as well. iii Acknowledgements It would be impossible for me to have completed this work entirely on my own. The enormous support of a number of people has contributed to the overall production of this thesis, through numerous valuable discussions, administrative support, and dedicated instruction. While it would take many additional pages to properly thank every person who has been a part of this work, I hope that this small section serves as representative of my sincerest thanks to all those involved. Without doubt, the departmental administrative assistants at both Queen’s University and Trent University have been invaluable in helping me achieve my goals. In particular, Ms. Annette Keyes, and Mrs. Laurie LaPlante are two people who have helped me enormously. Their tireless efforts will never be forgotten, and certainly, their efforts will remain at the forefront of my memories of graduate school. Additionally, members of the staff at each of the universities have been invaluable, as well. In particular, the help of Mr. John LaPlante, and Mr. Barry Best, along with Mr. Ralph Frederick, Mr. Ed Wilson, Mr. Paul Karrel, and Mr. Ken Fowler have been instrumental in ensuring that day to day research could continue, smoothly. I have also had the privilege of great instruction, in graduate courses at both Queen’s University and Trent University, and I would like to thankfully acknowledge the tireless efforts of all of my instructors, who have certainly helped me to learn chemistry in their own ways. iv Additionally, I would like to thank Professors Alan Slavin, and William Graham, who served as examiners on my committee. Their kind words, and thought provoking questions helped me to make my written thesis more complete. I am very pleased that both of them agreed to help me with this work, and provide their time, their advice, and their support. Without doubt, two of my instructors, Professor Donal Macartney, and Professor David Wardlaw, were the most inspirational, and my favourite instructors, at Queen’s. It was for this reason that I asked each of them to serve as members of my supervisory committee, and ultimately as examiners during my Ph.D. defence. I am very happy to have had these people along with me, during this journey. If I had to repeat the process, I would certainly hope that both of them would agree to repeat it with me, since they have certainly helped to make my overall Ph.D. experience exceptional. Finally, I could not conceive of writing this section without thanking Professor J. Mark Parnis, my supervisor, my chemical mentor, and one of my best friends. Were it not for Mark, I would never have considered graduate school, and I would thus have missed out on countless opportunities which have proven, time and time again, to be the perfect choices for me. Through my conversations with Mark, I have learned as much about life as I have about chemistry – and these lessons that I have learned in each case, will undoubtedly serve me well as I continue forward from this point. It is a consequence of these experiences that I have become the person that I am today. I am very proud to be completing this work, in this context, and if I am able to help even one person v have but a fraction of the experience I had during my Ph.D., I would consider that to be a great success. vi In memory of my grandfather, Jack Rascon While he would have realized in advance that he would not have understood a single concept, he would have sat and read this entire document, simply because I had written it. Then, during my convocation, he would have clapped louder, stood taller, and been filled with more pride than anyone has ever been. vii Statement of originality I hereby certify that all of the work described within this thesis is the original work of the author. Any published (or unpublished) ideas and/or techniques from the work of others are fully acknowledged in accordance with the standard referencing practices. Matthew Gary Karl Thompson November, 2007 viii Table of Contents Abstract .................................................................................................................ii Acknowledgements ..............................................................................................iv Statement of originality .......................................................................................viii Table of Contents .................................................................................................ix List of Tables .......................................................................................................xii List of Figures, Illustrations and Schemes ..........................................................xiii Chapter 1: Introduction ....................................................................................... 1 1.0 Origins of the current work........................................................................ 1 1.1 Matrix isolation: Technique and spectroscopic analysis .......................... 3 1.2 UV-visible spectroscopy and matrix isolation............................................ 9 1.3 Infrared spectroscopy and matrix isolation.............................................. 13 1.4 General introduction to basic organometallic chemistry.......................... 26 1.5 References for Chapter 1........................................................................ 30 Chapter 2: Review of transition metal reactivity with hydrocarbons: theory, gas- phase and matrix-isolation studies ..................................................................... 33 2.0 Overview of transition metal chemistry ................................................... 33 2.1 Transition metal chemistry with hydrocarbons ........................................ 34 2.2 Computational investigations of metal atoms with ethene ...................... 35 2.3 Gas-phase transition metal reactions with hydrocarbons........................ 45 2.4 Transition metal reactions with hydrocarbons in cryogenic matrices ...... 55 2.5 Water in inert gas matrices ..................................................................... 55 2.6 Ethene in inert gas matrices ................................................................... 57 2.7 Metal atoms in inert gas matrices ........................................................... 60 2.8 Reactions of metal atoms with ethene in inert matrices.......................... 68 2.9 References for Chapter 2........................................................................ 82 Chapter 3: Experimental and theoretical methods used for the analysis of reactions involving transition metal centres with organic substrates................... 88 3.0 Overview of technical section ................................................................. 88 3.1 Basic experiments in the matrix isolation system.................................... 88 3.1.1 Experimental system for studying transition metal reactions................ 90 3.1.2 The vacuum system used for matrix isolation experiments
Load more

Recommended publications
  • Matrix-Isolation FTIR Study of Azidoacetone and Azidoacetonitrile M
    LOW TEMPERATURE PHYSICS VOLUME 29, NUMBER 9–10 SEPTEMBER–OCTOBER 2003 Matrix-isolation FTIR study of azidoacetone and azidoacetonitrile M. Frankowski,* B. S. Fox, A. M. Smith-Gicklhorn, M. K. Beyer, and V. E. Bondybey** Institute of Physical and Theoretical Chemistry, Technical University of Munich, Garching 85747, Germany M. Algarra and M. L. Costa CEFITEC, Department of Physics, Fac. Sciences and Technology, Universidade Nova de Lisboa, Caparica P-2829-516, Portugal P. Rodrigues and M. T. Barros CQFB, Department of Chemistry, Fac. Sciences and Technology, Universidade Nova de Lisboa, Caparica P-2829-516, Portugal M. N. D. S. Cordeiro REQUIMTE, Department of Chemistry, Fac. Sciences, Universidade do Porto, Porto 4169-007, Portugal Fiz. Nizk. Temp. 29, 1140–1146 ͑September–October 2003͒ Azidoacetonitrile (N3CH2CN) and azidoacetone (N3CH2COCH3) are studied by matrix-isolation FTIR spectroscopy in solid neon, argon, and nitrogen. The IR spectra calculated using the density-fuctional theoretical method are discussed in comparison with the experimental data. Significant broadening of the recorded azide bands indicate an awkward fit of these compounds into the solid environment. The strongest absorption is observed for both compounds in the regions of asymmetric and symmetric stretches of the N3 azide group. Strong band splittings in the N3 asymmetric stretch region can be most likely explained by very strong Fermi resonances with the CN stretch and combinations and overtones of the numerous lower- frequency vibrational modes. © 2003 American Institute of Physics. ͓DOI: 10.1063/1.1619361͔ INTRODUCTION EXPERIMENTAL Sample preparation Organic azides are useful reagents in many fields.1–3 Their strongly exothermic reactions make them useful as Azidoacetonitrile was synthesized from chloroacetoni- 4 propellants.
    [Show full text]
  • Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbon Ions
    J. Phys. Chem. A 2000, 104, 3655-3669 3655 Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbon Ions. 5. PAHs Incorporating a Cyclopentadienyl Ring† D. M. Hudgins,* C. W. Bauschlicher, Jr., and L. J. Allamandola NASA Ames Research Center, MS 245-6, Moffett Field, California 94035 J. C. Fetzer CheVron Research Company, Richmond, California 94802 ReceiVed: NoVember 5, 1999; In Final Form: February 9, 2000 The matrix-isolation technique has been employed to measure the mid-infrared spectra of the ions of several polycyclic aromatic hydrocarbons whose structures incorporate a cyclopentadienyl ring. These include the cations of fluoranthene (C16H10), benzo[a]fluoranthene, benzo[b]fluoranthene, benzo[j]fluoranthene, and benzo- [k]fluoranthene (all C20H12 isomers), as well as the anions of benzo[a]fluoranthene and benzo[j]fluoranthene. With the exception of fluoranthene, which presented significant theoretical difficulties, the experimental data are compared to theoretically calculated values obtained using density functional theory (DFT) at the B3LYP/ 4-31G level. In general, there is good overall agreement between the two data sets, with the positional agreement between the experimentally measured and theoretically predicted bands somewhat better than that associated with their intensities. The results are also consistent with previous experimental studies of polycyclic aromatic hydrocarbon ions. Specifically, in both the cationic and anionic species the strongest ion bands typically cluster in the 1450 to 1300 cm-1 range, reflecting an order-of-magnitude enhancement in the CC stretching and CH in-plane bending modes between 1600 and 1100 cm-1 in these species. The aromatic CH out-of- plane bending modes, on the other hand, are usually modestly suppressed (e 2x - 5x) in the cations relative to those of the neutral species, with the nonadjacent CH modes most strongly affected.
    [Show full text]
  • Southwest Retort
    SOUTHWEST RETORT SIXTY-NINTH YEAR OCTOBER 2016 Published for the advancement of Chemists, Chemical Engineers and Chemistry in this area published by The Dallas-Fort Worth Section, with the cooperation of five other local sections of the American Chemical Society in the Southwest Region. Vol. 69(2) OCTOBER 2016 Editorial and Business Offices: Contact the Editor for subscription and advertisement information. Editor: Connie Hendrickson: [email protected] Copy Editor: Mike Vance, [email protected] Business Manager: Danny Dunn: [email protected] The Southwest Retort is published monthly, September through May, by the Dallas-Ft. Worth Section of the American Chemical Society, Inc., for the ACS Sections of the Southwest Region. October 2016 Southwest RETORT 1 TABLE OF CONTENTS Employment Clearing House………….......3 Fifty Years Ago……………………….….....6 ARTICLES and COLUMNS Schulz Award Winner Gale Hunt………….7 And Another Thing……………………….11 Around the Area………………………….14 Letter from the Editor….…..……….........17 SPECIAL EVENTS National Chemistry Week…………………9 NEWS SHORTS Former pesticide ingredient found in dolphins, birds and fish……………………8 Coffee-infused foam removes lead from contaminated water………………………10 Snake venom composition could be related to hormones and diet……………………..13 Detecting blood alcohol content with an electronic skin patch………………...……16 INDEX OF ADVERTISERS Huffman Laboratories……………....……..4 Contact the DFW Section Vance Editing…..…………….…….……….4 General: [email protected] UT Arlington………………………………..4 Education: [email protected] ANA-LAB……………………...….…...……5 Elections: [email protected] Facebook: DFWACS Twitter: acsdfw October 2016 Southwest RETORT 2 EMPLOYMENT CLEARING HOUSE Job applicants should send name, email, and phone, along with type of position and geographical area desired; employers may contact job applicants directly.
    [Show full text]
  • Nanochemistry Views Geoffrey A
    Nanochemistry Views Geoffrey A. Ozin Nanochemistry Views Geoffrey A. Ozin Materials Chemistry and Nanochemistry Research Group, Center for Inorganic and Polymeric Nanomaterials, Chemistry Department, 80 St. George Street, University of Toronto, Toronto, Ontario, Canada M5S 3H6 After more than four and a half decades of research in the field of nanochemistry I was given the interesting opportunity to write a monthly opinion editorial for the Nano Materials Views section of the VCH-Wiley materials journals, Advanced Science, Advanced Materials, Advanced Functional Materials, Small, Particle, Advanced Engineering Materials, Advanced Optical Materials and Advanced Health Materials. This chance provided me with a superb vehicle to express opinionated and provocative views about hot button issues in nanochemistry. Dreaming up and composing these editorials has been a valuable lesson in how to write scientifically, technologically and politically correct critiques about controversial topics for a public forum, a pastime less risky for a senior scientist than a junior one. After having produced 36 of these opinion editorials on a variety of contemporary topics in nanochemistry, I thought it worthwhile to integrate them into a compendium of essays in the form of a monograph entitled Nanochemistry Views as a three score years and ten plus one, milestone in my life. I hope the reader enjoys these stories as much as I had fun writing them and at the same time learning much from knowledgeable colleagues who contributed insightful and important commentaries on my opinions, sometimes voicing heterodox views, many of which in anonymous form I included in much improved final drafts. I also received terrifically helpful editing on more-or-less every story from my talented and dynamic group of co-workers as well as excellent artistic renditions of the content of many of the stories from Wendong Wang, Chenxi Qian and ArtScientist Todd Siler.
    [Show full text]
  • Matrix Isolation and Computational Study of Isodifluorodibromomethane (F2 Cbr-Br): a Route to Br2 Formation in Cf2 Br2 Photolysis
    Bowling Green State University ScholarWorks@BGSU Chemistry Faculty Publications Chemistry 2010 Matrix Isolation and Computational Study of Isodifluorodibromomethane (F2 Cbr-Br): A Route to Br2 Formation in Cf2 Br2 Photolysis Alexander N. Tarnovsky Bowling Green State University, [email protected] Lisa George Aimable Kalume Patrick Z. El-Khoury Scott A. Reid Follow this and additional works at: https://scholarworks.bgsu.edu/chem_pub Part of the Chemistry Commons Repository Citation Tarnovsky, Alexander N.; George, Lisa; Kalume, Aimable; El-Khoury, Patrick Z.; and Reid, Scott A., "Matrix Isolation and Computational Study of Isodifluorodibromomethane (F2 Cbr-Br): A Route to Br2 Formation in Cf2 Br2 Photolysis" (2010). Chemistry Faculty Publications. 26. https://scholarworks.bgsu.edu/chem_pub/26 This Article is brought to you for free and open access by the Chemistry at ScholarWorks@BGSU. It has been accepted for inclusion in Chemistry Faculty Publications by an authorized administrator of ScholarWorks@BGSU. THE JOURNAL OF CHEMICAL PHYSICS 132, 084503 ͑2010͒ Matrix isolation and computational study of isodifluorodibromomethane „F2CBr–Br…: A route to Br2 formation in CF2Br2 photolysis Lisa George,1 Aimable Kalume,1 Patrick Z. El-Khoury,2 Alexander Tarnovsky,2 and ͒ Scott A. Reid1,a 1Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, USA 2Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, USA ͑Received 29 November 2009; accepted 26 January 2010; published online 22 February 2010͒ ͑ ͒ The photolysis products of dibromodifluoromethane CF2Br2 were characterized by matrix isolation infrared and UV/Visible spectroscopy, supported by ab initio calculations. Photolysis at ͑ϳ ͒ ϳ wavelengths of 240 and 266 nm of CF2Br2 :Ar samples 1:5000 held at 5 K yielded ͑ ͒ iso-CF2Br2 F2CBrBr , a weakly bound isomer of CF2Br2, which is characterized here for the first time.
    [Show full text]
  • Cryochemistry in the Inert and Interstellar Media
    Cryochemistry in the inert and interstellar media Serge A. Krasnokutski Friedrich Schiller MPI for Astronomy, University of Jena, Königstuhl 17,69117 07740 Jena, Germany Heidelberg, Germany Holes in heaven Herschel, W., Phil. Trans. 75, 213 (1785) T = 10 - 50 K The Boomerang Nebula T = 1 K Motivation k = A e-Ea / RT T = 0.37 K T = 10 - 50 K Reaction of Al atoms with oxygen molecules Al + O2 →AlO + O J. Phys. Chem. A 101, 9988 (1997) Reaction of Si atoms with oxygen molecules T = 0.37 K k > 5 × 10-14 cm3 mol-1 s-1 6.7 × 10-29 0.1 0.37 1 1.77 × 10-82 1.46 × 10-16 Astron. Astrophys. 372, 1064 (2001) J. Phys. Chem. A 114, 13045 (2010) Chemical models of reactions in the ISM Gas-phase or grain-surface reactions? Grain-surface reactions A + B → AB Gas-phase reactions A + B → C + D desorption accretion Grain hopping Grain-surface reactions can be affected by catalytic activity of the grain surface. However, the exact chemical composition of the cosmic dust grains is not known. The matrix isolation scheme The matrix isolation experimental setup Formation of (SiO)n clusters in Ne matrix Astrophys. J. 782, 10pp (2014) Formation of SiO bulk after evaporation of Ne matrix Astrophys. J. 782, 10pp (2014) Formation of SiO bulk after evaporation of Ne matrix Astrophys. J. 782, 10pp (2014) The He droplet experimental setup The properties of helium nanodroplets • The temperature of the He droplets is well known (T = 0.37 K). • The He droplets are superfluid.
    [Show full text]
  • Arghya Chakraborty
    Electronic Characterization of Mass-Selected Acyclic, Polycyclic and Oxygenated Hydrocarbons in Neon Matrices INAUGURALDISSERTATION zur Erlangung der Würde eines Doktors der Philosophie vorgelegt der Philosophisch-Naturwissenschaftlichen Fakultät der Universität Basel von Arghya Chakraborty aus Westbengal, Indien Basel, 2016 Originaldokument gespeichert auf dem Dokumentenserver der Universität Basel edoc.unibas.ch 1 Genehmigt von der Philosophisch-Naturwissenschaftlichen Fakultät auf antrag von Dissertationsleiter: Prof. Dr. John. P. Maier Korreferent: Prof. Dr. Stefan Willitsch Basel, 23 Februar 2016 Prof. Dr. J. Schibler Dekan 2 Electronic Characterization of Mass-Selected Acyclic, Polycyclic and Oxygenated Hydrocarbons in Neon Matrices PhD THESIS Of ARGHYA CHAKRABORTY Basel 2016 3 4 Acknowledgements A researcher needs a healthy working atmosphere to be productive. The work and personal life in Basel would not have been so pleasant without the guidance and support of several individuals. First of all, I would like to thank Prof. John Paul Maier for his constant endorsement, supervision and providing world class experimental facilities in laboratory. Beside science, I have learned lots of technical skills from him and hopefully will apply them in my entire career. I am very much thankful to Prof. Stefan Willitsch for being the co-referee of my thesis. Prof. Markus Meuwly is thanked for accepting to be the chair in my PhD defense. Heartiest thank of mine goes to Dr. Jan Fulara for teaching me the essentials of the matrix isolation set-up, sharing his deep knowledge on spectroscopy and helping with his computational skill. Special thanks are also addressed to Dr. Corey Rice for his advices, explanations and experimental ideas. I am highly privileged to him for being the proof reader of my thesis.
    [Show full text]
  • Nasaaerospace Database Subject Scope ... an Overview
    NASA SP-7107 NASA Aerospace Database Subject Scope ... An Overview National Aeronautics and Space Administration Scientific and Technical Information Program Washington, DC 1993 This publication was prepared by the NASA Center for AeroSpace Information, 800 Elkridge Landing Road, Linthicum Heights, MD 21090-2934, (301) 621-0390. NASA Aerospace Database Subject Scope ... An Overview The NASA Scientific and Technical Information (STI) Program manages the vast amount of information pertinent to aerospace research and development and makes this information available to NASA and the aerospace community worldwide. The main tool in carrying out this mission is the NASA Aerospace Database, a publicly available subset of the NASA STI Database. The NASA Aerospace Database contains over 2,000,000 citations to reports, journal articles, and other publications. This booklet outlines the subject scope of the NASA Aerospace Database. It lists the topics of interest to NASA and places them within the framework of broad aerospace subject catagories. For detailed explanations of the subjects themselves, see the NASA Scientific and Technical Information System ... Its Scope and Coverage, December 1988 (NASA SP-7065). SUBJECTS AERONAUTICS 15-04 Scientific Satellites 15-05 Reentry Vehicles 15-06 U.S.S.R. Spacecraft 01 Aeronautics (General) 02 Aerodynamics 16 Space Transportation 02-01 Aerodynamic Characteristics 16-01 Space Transportation and Manned Spacecraft 02-02 Aerodynamics of Bodies 17 Space Communications, Spacecraft Communica- 02-03 Airfoil and Wing
    [Show full text]
  • Spectroscopy in Helium Nanodroplets: Studying Relaxation Mechanisms in Nature's Most Fascinating Solvent
    Spectroscopy in Helium Nanodroplets: Studying Relaxation Mechanisms in Nature’s Most Fascinating Solvent Andr´eConjusteau A DISSERTATION PRESENTED TO THE FACULTY OF PRINCETON UNIVERSITY IN CANDIDACY FOR THE DEGREE OF DOCTOR OF PHILOSOPHY RECOMMENDED FOR ACCEPTANCE BY THE DEPARTMENT OF CHEMISTRY June 2002 c Copyright by Andr´eConjusteau, 2002. All rights reserved. ii Abstract Helium nanodroplet isolation spectroscopy has recently been developed to combine materials science and chemical dynamics studies at very low temperatures. The technique, a combination of beam and matrix isolation spectroscopy, shows great promise as a tool to study both the solvent properties of superfluid helium, and the relaxation dynamics of impurities embedded in it. This thesis presents two experiments designed to improve our understanding of solvation in superfluid helium. Firstly, an experiment aimed at the formation in situ of radicals in helium nanodroplets has been performed. The photodissociation of NO2 embedded in he- lium, using a high repetition rate narrowband U.V. laser, has been attempted. The experiment led to the surprising result that, even 2000 cm−1 above the gas phase threshold, no signature of dissociation could be observed. Secondly, a predicted limitation of a successful hydrodynamic model built to explain the increase in moment of inertia of molecules solvated in helium has been probed by microwave spectroscopy. The observation of the pure rotational spectra of isotopically substituted species (HCN/DCN, and CH3F/CD3F), leads to the unequivocal conclusion that the angular velocity of the rotor greatly affects its helium–induced increase in moment of inertia. For the cyanides, it has been found iii that HCN, which is faster than DCN by 23% in the gas phase, sees its moment of inertia increase less (by 11%) than that of DCN.
    [Show full text]
  • Cryochemistry of Metal Nanoparticles
    Journal of Nanoparticle Research 5: 529–537, 2003. © 2003 Kluwer Academic Publishers. Printed in the Netherlands. Cryochemistry of metal nanoparticles Gleb B. Sergeev Laboratory of Low Temperature Chemistry, Chemistry Department, Moscow State University, 119899, Moscow, Russia (Tel.: +7(095)939 5442; Fax: +7(095)939 0283; E-mail: [email protected]) Received 20 March 2003; accepted in revised form 23 May 2003 Key words: metal nanoparticles, low temperature, solid state, encapsulation, sensor materials, spectroscopy, explosive reactions Abstract The interaction of metal atoms, clusters and nanoparticles with different organic and inorganic substances were studied at low temperature (10–40 K). Combination of matrix isolation technique and preparative cryochemistry was applied for the investigation of activity and selectivity of metal particles of different size. Encapsulation of metal nanoparticles in polymers was studied. The metal–polymer films thus obtained exhibited satisfactory sensitivity to ammonia. Introduction isolation technique and preparative cryochemistry. The interaction of metal particles with different organic The last decade of the 20th century was marked by the and inorganic substances will be presented in the first increased attention of scientists in the fields of physics, part of this article. In the second part we will consider chemistry, material science, etc., devoted to nanoparti- the encapsulation of metal nanoparticles in polymer cles, their synthesis, properties and different reactions. films and thus obtaining the nanosystems, exhibited The reason for this lies in the fact that particles of sensor activity. nanometer size exhibit peculiar properties. At present time the most interesting subject is the connection of chemical properties of metallic particles Reactions in low temperature with their size.
    [Show full text]
  • "Carbon-Nitrogen Chain Molecules in the Laboratory and in Interstellar
    CARBON-NITROGEN CHAIN MOLECULES IN THE LABORATORY AND IN INTERSTELLAR MEDIUM BY ROBERT KOŁ OS Institute of Physical Chemistry of the Polish Academy of Sciences Warsaw 2003 ISBN 83-913520-4-8 2 to the memory of my Father 3 4 Preface Science sans conscience n’est que ruine de l’âme. –Rabelais (1532) The simplest and broadest definition of the interstellar matter – “everything but stars” – may be misleading. Is Earth a piece of it? Are humans the interstellar matter, with all material products of the terrestrial civilization? Avoiding the perils of semantics, I will rather use the term in its narrow sense. In what follows, it will primarily be applied to immense clouds of gas and dust, without which the stars would have nothing to be born from, and – when their time comes – nothing to disperse into. It is only 35 years now, since an important, yet largely unnoticed discovery has been made. The interstellar matter was found to be more than just hydrogen, helium, mineral dust, and a small admixture of heavier atoms, their ions, and few simplest diatomics – as was originally believed. In addition to this blend (not very promising for a chemist) the presence of quite complex organic molecules was revealed. By plain chemical standards, some of the compounds given the “interstellar” tag may seem bizzare (or useless), like the largest ones: rod-shaped polyacetylenic nitriles. Still, all these merit our closest attention. If a molecule is abundant enough to show up in the interstellar medium – in spite of present rudimentary detection methods – then it inevitably has to be conceived as one of most important arrangements of atoms in the Galaxy, and possibly also in the entire Universe.
    [Show full text]
  • Perspective on Cryochemistry
    Perspective Chemical Sciences Journal Volume 12:6, 2021 ISSN: 2150-3494 Open Access Perspective on Cryochemistry Michael Bratychak Department of Petroleum Chemistry and Technology, Lviv Polytechnic National University, Ukraine volume. The acceleration caused by the concentration effect is greater than the Perspective inhibition caused by freezing, thus the final manifestation is that the chemical reaction is accelerated by freezing. It is counterintuitive that chemical reactions can be accelerated by freezing, but this amazing phenomenon was discovered as early as the Since the 1960s, it has been known that freezing can accelerate certain 1960s. In frozen systems, the increase in reaction rate is caused by various chemical reactions. For example, the reaction rate of ethylene chlorohydrin mechanisms and the freeze concentration effect is the main reason for the and sodium hydroxide in was increased by 1000-fold in a frozen solution. This observed acceleration. Some accelerated reactions have great application phenomenon could be explained by the freeze concentration effect: at 5°C, value in the chemistry synthesis and environmental fields; at the same 0.001 M initial reactant concentration, 99.9% of the frozen solution was solid, time, certain reactions accelerated at low temperature during the storage of and the reaction would proceed at 1000 times the initial rate in the remaining food, medicine, and biological products should cause concern. The study of 0.1% of liquid. Besides, the study on the stability of penicillin amide bonds has reactions accelerated by freezing will overturn common sense and provide a found that β-lactam bonds were unusually cleaved in frozen systems. Penicillin new strategy for researchers in the chemistry field.
    [Show full text]