Nuclear Magnetic Resonance Spectroscopy of Liquid Crystals PDF
Preview Nuclear Magnetic Resonance Spectroscopy of Liquid Crystals
7310tpCast.indd 1 8/14/09 10:29:19 AM TThhiiss ppaaggee iinntteennttiioonnaallllyy lleefftt bbllaannkk 7310tpCast.indd 2 8/14/09 10:29:20 AM Published by World Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore 596224 USA office: 27 Warren Street, Suite 401-402, Hackensack, NJ 07601 UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY OF LIQUID CRYSTALS Copyright © 2010 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. This book, or parts thereof, may not be reproduced in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from the Publisher. For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to photocopy is not required from the publisher. ISBN-13 978-981-4273-66-4 ISBN-10 981-4273-66-X Printed in Singapore. ZhangFang - Nuclear Magnetic Resonance.pmd1 8/6/2009, 2:12 PM June24,2009 19:32 WorldScienti(cid:12)cReviewVolume-9inx6in preface Preface The diversity of Liquid Crystals is evident in everyday life in incarnations ranging from liquid-crystal displays to biological membranes. It is there- fore important to have a good understanding of these materials to further the progress in this (cid:12)eld of research and development. To achieve this, no single technique, whether it is theory or experiment, can provide a clear understandingof the fundamental physics and chemistryof liquid crystals. There is no doubt that the liquid-crystal(cid:12)eld is interdisciplinaryin nature and requires the expertise of biologists, chemists, physicists, engineers and materials scientists. Indeed it also provides a ground for cross-fertilization ofdi(cid:11)erentresearchareastoachievenewpotentialapplicationsinthe(cid:12)elds of telecommunication, medicine, memory devices and beyond. Nuclear magnetic resonance is one of the experimental techniques that were used early on (in the early nineteen sixties) to unravel and harness the intrin- sic anisotropic potential that exists in these materials. Given the number of NMR active nuclei, the wealth of modern NMR pulse techniques and the technical advances in NMR instrumentation, the happy marriage be- tweenNMRandliquidcrystalsisclearlydemonstratedinthisvolume. The Editor has written a text that bears the same name as this volume some sixteenyearsago;hementionedthenthe limitationofasingle-authorbook isnecessarilyhamperedbythelimitedresearchinterestsofthewriter. How- ever,themainaimwastolaydownthe theoreticalNMRandliquid-crystal physics backgroundfor the bene(cid:12)t of newcomers to the (cid:12)elds of NMR and LiquidCrystals. Anindicationof the successof that aimisthat thetextis being used by many graduate students and other researchers. The present edited volume certainly covers more diverse applications of NMR in liquid crystals,anditishopedthat thiscanserveasacompendium tothe earlier text. The volume contains the latest state-of-the-art developments in using NMR to study liquid crystals. Small solutes (as well as not so small pro- teins) in thermotropic and lyotropic liquid-crystal phases are discussed in v June24,2009 19:32 WorldScienti(cid:12)cReviewVolume-9inx6in preface vi Preface Chapters 1 to 4. These chapters are mainly focused on observed spectro- scopic (equilibrium) properties. These are followed by chapters on the liquid-crystal molecules using deuterium, proton or carbon-13 nuclei in thesemoleculesasprobestosensedynamicalpropertiesand/orstaticprop- erties like the orientational ordering and phase structure. The question of quenched disorder of a liquid crystal con(cid:12)ned in silica aerosolgel networks is studied in Chapter 7 by using deuterium probes located within the liq- uid crystal via chemical deuteriation. Chapters 5 and 8 deal with proton and deuterium spin relaxation, respectively, of numerous di(cid:11)erent liquid- crystallinephasesformedbymoleculesof increasinglycomplexanisometric shapes. Chapter6dealswithdeuteriumNMRofchiraltiltedphasesandthe e(cid:11)ectoftheNMR(cid:12)eld. Chapter9describesaprotonstudyofself-di(cid:11)usion ofliquid-crystalmoleculesbyutilizingthelargefringe(cid:12)eldgradientinasu- perconductingmagnet. Chapter10describesameansof combiningthe ex- ternalelectric(cid:12)eldandthe NMR (cid:12)eldtoprobethe directorreorientational dynamicsinadeuteratednematicliquidcrystal. Thedirectordynamicsand individual molecular motions (translation or reorientation)are closely tied tothe elasticandviscouspropertiesof liquid crystals. Chapter11provides a survey of theoretical approaches to treat viscoelastic properties of liquid crystals and to give possible relations between theoretical predictions and NMR observables. The remaining two chapters have to do with carbon-13 NMR of calamitic liquid crystals. The former one deals with the study of orientationalorderparameters,andmolecularconformationinrod-likeand bent-coremesogens. Thelatteroneprovidesacombineddensityfunctional theory and NMR study of a speci(cid:12)c bent-core liquid-crystal molecule that is known to exhibit in bulk a uniaxial and a biaxial nematic phase upon decreasing temperature. The scope of this volume is necessarily limited by its size and the ex- pertise of the contributors. However, it is our hope that it can provide a glimpseofthelatestnewsinthe(cid:12)eldofLiquidCrystals,inparticularwhat NMRcano(cid:11)ertoadvancetheunderstandingoftheunderlyingprinciplesin thistypeof softmatter. TheEditorismostgratefultoallthe contributors (and friends) to make his dream come true. He is also indebted to his wife Natalia for putting up with him days and nights as well as weekends on this book project. Ronald Y. Dong UBC, Vancouver, May 1, 2009 July29,2009 16:59 WorldScienti(cid:12)cReviewVolume-9inx6in contents Contents Preface v 1. Novel Strategies for Solving Highly Complex NMR Spectra of Solutes in Liquid Crystals E. E. Burnell, C. A. de Lange and W. Leo Meerts 1 2. Analytical Potentials of Natural Abundance Deuterium NMR Spectroscopy in Achiral Thermotropics and Polypeptide Chiral Oriented Solvents P. Lesot and C. Aroulanda 37 3. Noble Gas Probes in NMR Studies of Liquid Crystals J. Jokisaari 79 4. Bicelles { A Much Needed Magic Wand to Study Membrane Proteins by NMR Spectroscopy R. Soong, J. Xu and A. Ramamoorthy 117 5. Advances in Proton NMR Relaxometry in Thermotropic Liquid Crystals P. J. Sebastia~o, C. Cruz and A. C. Ribeiro 129 6. Deuterium NMR Study of Magnetic Field Distortions in Ferroelectric Mesogens R. Y. Dong 169 7. Deuteron NMR Study of the E(cid:11)ects of Random Quenched Disorder in 12CB Silica Dispersions D. Finotello and V. Pandya 201 vii July29,2009 16:59 WorldScienti(cid:12)cReviewVolume-9inx6in contents viii Contents 8. Dynamics of Liquid Crystals by means of Deuterium NMR Relaxation C. A. Veracini and V. Domenici 229 9. Translational Self-di(cid:11)usion Measurements in Thermotropics by means of Static Field Gradients NMR Di(cid:11)usometry M. Cifelli 263 10. Deuterium NMR Studies of Static and Dynamic Director Alignment for Low Molar Mass Nematics A. Sugimura and G. R. Luckhurst 301 11. Viscoelastic Properties of Liquid Crystals: Statistical-mechanical Approaches and Molecular Dynamics Simulations A. V. Zakharov 341 12. Carbon-13NMR Studies of Thermotropic Liquid Crystals R. Y. Dong 375 13. A Combined DFT and Carbon-13NMR Study of a Biaxial Bent-core Mesogen A. Marini, V. Prasad and R. Y. Dong 413 Subject Index 451 July29,2009 17:18 WorldScienti(cid:12)cReviewVolume-9inx6in chap1 Chapter 1 Novel Strategies for Solving Highly Complex NMR Spectra of Solutes in Liquid Crystals E. Elliott Burnell1, Cornelis A. de Lange2, and W. Leo Meerts3 1Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada V6T 1Z1 email: [email protected] 2Laser Centre, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands email: [email protected] 3Molecular and Biophysics Group, Institute for Molecules and Materials, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands and Physical Chemistry Department, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands email: [email protected] The application of liquid-crystal NMR to solutes with more than eight spins has for decades been hampered bythe extremely high complexity of the spectra. We describe recent experimental and novel theoretical advances to address the central problem of spectral analysis. Experi- mentally the application of multiple-quantum NMR is shown to be a powerful tool. Moreover, theoretical algorithms from evolutionary biol- ogy are applied to NMR of solutes in anisotropic environments. These novelspectral(cid:12)ttingproceduresareaidedbyestimatesofthesolutede- gree of orientational order, based on simple phenomenological size and shape models. The apparent success of these approaches has consider- ably extendedthe realm of applications of NMRin ordered liquids. 1.1. Introduction TheHamiltonianthatdescribesthehigh-resolutionNMRspectraofsolutes dissolved in anisotropic solvents is well known and has proved to be an excellentpredictorforsuchdetailedexperimentalinformation. Theparam- 1
The list of books you might like
