[2]Rotaxanes for Artificial Molecular Machines
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Mie University Department of Chemistry for Materials
Mie University Department of Chemistry for Materials General Principles and Selected Examples in Supramolecular Chemistry Prof. Yang Kim ([email protected]) Kumamoto University 2. Solution host-guest chemistry 2.1 Introduction: guests in solution The host–guest chemistry of anions, cations and neutral-guest species in solution. The electrostatic charge on any ion must be balanced by a corresponding counter-ion. Thus a ‘cation’ or ‘anion’ host is always a host for an ion pair (either contact or solvent-separated). The effect of the counter-ion is sometimes ignored or assumed to be negligible, particularly + - − if weakly interacting counter-ions are used, such as NBu 4 , PF 6 , or B(C 6H3(CF 3)2)4 . However, there are a number of successful ion-pair binding hosts . Macrocyclic receptor that binds solvent separated ion-pairs Association of ZnDPA probe with phosphatidylserine head group. False colored fluorescence image of a living rat bearing two tumors. 2.2 Macrocyclic versus acyclic hosts Two major classes of host: acyclic (podands ) and cyclic (macrocycles, macrobicycles or macrotricycles ). Podand : An acyclic chain-like or branching host with a number of binding sites that are situated at intervals along the length of the molecule, or about a common spacer. Podand: Linear or branching chain species with two or more sets of guest-binding functional groups positioned on the spacer unit in such a way as to chelate a target guest species to maximise guest affinity (cf . co-operativity ). Podands generally have a high degree of flexibility and on binding to a guest the conformational change that occurs to produce a stable host–guest complex, may result in allosteric effects . -
Thesis Style Document
Studies Towards the Asymmetric Synthesis of Cyclochiral Rotaxanes and Au(III)-oxo Complexes as Catalysts James Alan Thomas O’Neill Submitted for the degree of Doctor of Philosophy Heriot-Watt University School of Engineering and Physical Sciences April 2015 The copyright in this thesis is owned by the author. Any quotation from the thesis or use of any of the information contained in it must acknowledge this thesis as the source of the quotation or information. ABSTRACT The work reported in this thesis consists of studies towards the asymmetric synthesis of mechanically planar chiral rotaxanes via desymmetrisation approach. It describes the synthesis of a novel macrocycle and the investigation of this macrocycle as a potential ligand in the Cadiot-Chodkiewicz and CuAAC ‘click’ reactions as part of the study towards the synthesis of asymmetric planar chiral rotaxanes. Furthermore, the use of Au(III)-oxo complexes as potential catalysts in a model hydroamination reaction are described. The thesis is divided into four chapters: Chapter one is an introduction to rotaxanes and includes an overview of the synthesis of rotaxanes and chirality in rotaxanes. Chapter two is an account of the synthesis of a novel macrocycle and details attempts to implement this macrocycle towards the synthesis of a rotaxane using the Cadiot- Chodkiewicz and CuAAC ‘click’ reactions. Chapter three describes optimisation and multi-gram scale-up of the synthetic route towards a novel C1-symmetric bis(oxazoline) macrocycle first synthesised in our group by Pauline Glen. Chapter four describes our investigation into the use of Au(III)-oxo complexes for use as catalysts in a model hydroamination reaction. -
Study the Important Characteristics of the Macrocyclic Complexes
INTERNATIONAL JOURNAL OF RESEARCH CULTURE SOCIETY ISSN: 2456-6683 Volume - 1, Issue - 08, Oct – 2017 UGC Approved Monthly, Peer-Reviewed, Refereed, Indexed Journal Publication Date: 30/10/2017 STUDY THE IMPORTANT CHARACTERISTICS OF THE MACROCYCLIC COMPLEXES Sneha Thahiya1 Dr.Dheeraj Kumar2 1 Research scholar Singhania university Rajasthan 2 Assistant professor government college Narnaul Haryana Email - [email protected] Abstract: The metal-ion and host-guest chemistry of macro cyclic ligands have developed rapidly over recent years and now impinge on wide areas of both chemistry and biochemistry. Macro cyclic ligands are polydentate ligands containing their donor atoms either incorporated in or, less commonly, attached to a cyclic back bone. A large number of synthetic, as well as many natural, macro cycles have now been studied in considerable depth. A major thrust of many of these studies has been to investigate the unusual properties frequently associated with cyclic ligand complexes. In particular, the investigations of spectral, electrochemical, structural, kinetic and thermodynamic aspects of macro cyclic complex formation have all received considerable attention. Key Words: Macro cyclic ligands, Cyclic ligand complexes, host-guest Addition etc. 1. INTRODUCTION : The development of the field of bioinorganic chemistry has been an important factor in spurring the growth of interest in the macro cyclic complexes. The possibility of using synthetic macro cycle as model for biologically important system has initiated a broad spectrum of research activities, ranging from synthesis of new ring systems and studies on the properties and function of macro cyclic complexes to their application in industry, medicine and other field. The field of macro cyclic chemistry of metals is developing very fast because of its variety of applications and importance in the area of coordination chemistry. -
Novel Metal Template Strategies for the Construction of Rotaxanes and Catenanes
Novel Metal Template Strategies for the Construction of Rotaxanes and Catenanes Roy T. McBurney Degree of Doctor of Philosophy School of Chemistry The University of Edinburgh December 2008 Dedicated to My Family i Contents Abstract and Layout of Thesis .................................................................................... v Declaration .............................................................................................................. vii Lectures and Meetings Attended and Presentations Given ....................................... viii Acknowledgements .................................................................................................... x General Comments on Experimental Data ................................................................ xii Chapter 1: Recent Advances in the Metal Template Synthesis of Catenanes, Rotaxanes, Knots and Links 1 Synopsis .................................................................................................................... 2 1.1 Ordering and Entwining about a Metal Template ................................................. 3 1.2 “Passive” Metal Template Synthesis of Rotaxanes and Catenanes ........................ 7 1.3 Knots ................................................................................................................. 28 1.4 Borromean Rings ............................................................................................... 33 1.5 “Active” Metal Template Synthesis of Rotaxanes ............................................. -
Managing Tight Binding Receptors for New
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he Most Powerful Ligands--An Under Utilized Resource . 6 A Limiting Moleular Lethargy. 7 Exploiting and Overcoming that Molecular Lethargy. 7 METHODS AND RESULTS Principles of Tight-binding by Ligands. 8 Replacing Equilibration with More Rapid Switching Processes . 9 Design and Synthesis of Generation 1 Switch-binding Ligands . 9 Validation of Concept: Studies on In Situ Produced Generation 0 Ligand. 11 Proof of the Template Switch-binding Concept Using Generation 1 Ligand . 13 Generation 2 Ligands-- an Untested Second Example . 18 Switch-release Studies--A replacement for Slow Equilibrium Release . 19 Photorelease of Metal Ions from Tightly Bound Adducts . 19 Slow Separations Methodology--an Extreme Case of Biomimicry . 20 Macroporous Polymers. 21 Polymer Synthesis . .21 Polymer Characterization. 22 RELEVANCE, IMPACT AND TECHNOLOGY TRANSFER Relevance to Critical DOE Environmental Management Problems . 23 Deactivation and Decommissioning.. 24 Environmental Restoration. 24 High-level Waste. 24 MLLW/TRU and Spent Nuclear Fuel. 25 Reducing Costs, Schedules and Risks and Improved Compliance. 25 Bridging the Gap between Basic Research and Timely Needs-Driven Applications. 25 Impact on possible Users and the Identification of Those Users . 26 Are Larger Scale Trials Warranted?. -
NMR Studies of Inclusion Compounds
NMR Studies of Inclusion Compounds Sahar Nikkhou Aski Stockholm University © Sahar Nikkhou Aski, Stockholm 2008 ISBN 978-91-7155-715-5 Printed in Sweden by US-AB, Stockholm 2008 Distributor: Department of Physical, Inorganic and Structural Chemistry Stockholm University ii NMR Studies of Inclusion Compounds Sahar Nikkhou Aski Abstract This thesis presents the application of some of the NMR methods in studying host- guest complexes, mainly in solution. The general focus of the work is on investigating the reorientational dynamics of some small molecules that are bound inside cavities of larger moieties. In the current work, these moieties belong to two groups: cryptophanes and cyclodextrins. Depending on the structure of the cavities, properties of the guest molecules and the formed complexes vary. Chloroform and dichloromethane are in slow exchange between the cage-like cavity of the cryptophanes and the solvent, on the chemical shift time scale, whereas adamantanecarboxylic acid, quinuclidine and 1,7-heptanediol in complex with cyclodextrins are examples of fast exchange. Kinetics and thermodynamics of complexation are studied by measuring exchange rates and translational self- diffusion coefficients by means of 1-dimenssional exchange spectroscopy and pulsed-field gradient (PFG) NMR methods, respectively. The association constants, calculated using the above information, give estimates of the thermodynamic stability of the complexes. Carbon-13 spin relaxation data were obtained using conventional relaxation experiments, such as inversion recovery and dynamic NOE, and in some cases HSQC-type (Hetereonuclear Single Quantum Correlation Spectroscopy) experiments. Motional parameters for the free and bound guest, and the host molecules were extracted using different motional models, such as Lipari- Szabo, axially symmetric rigid body, and Clore models. -