PřF:C8951 Solid-State NMR Spectroscopy - Course Information

C8951 Solid-State NMR Spectroscopy - Basic Principles and Application in Chemistry.

Extent and Intensity

1/0/0. 1 credit(s) (fasci plus compl plus > 4). Recommended Type of Completion: zk (examination). Other types of completion: k (colloquium).

Teacher(s)

Ing. Jiří Brus, PhD. (lecturer)
prof. RNDr. Radek Marek, Ph.D. (lecturer)

Guaranteed by

prof. RNDr. Radek Marek, Ph.D.
National Centre for Biomolecular Research – Faculty of Science

Prerequisites

basic knowledge of physics, chemistry, and NMR in solution

Course Enrolment Limitations

The course is offered to students of any study field.

Course objectives

Not only basic principles of solid-state NMR spectroscopy are presented in twelve courses. Predominantly current trends of solid-state NMR providing precise determination of structure and dynamics of relatively rigid molecular systems are introduced and discussed in detail. Recent methodology and hardware development significantly increase resolution and selectivity of solid-state NMR experiment that can now provide detailed information about structure and segmental dynamics of wide range of materials. Consequently, solid-state NMR spectra are often comparable with quality of high-resolution NMR spectra of solutions and liquids. That is why the basic principles of traditional and recently developed "averaging" techniques are summarized in several initial courses. However, the largest area is reserved for the discussion of multi-dimensional correlation and separation experiments making possible to precisely probe structure, conformation and segmental dynamics of the molecular systems at natural isotopic abundance. On the other hand, not even experimental techniques exclusively designed for the determination of global structure of uniformly labeled polypeptides and proteins stand aside and they are briefly introduced and discussed as well. Final courses are devoted to the experimental procedures involving quadrupolar nuclei with spin larger than and to basic technical (experimental) preconditions, which must be fulfilled to successfully perform solid-state NMR experiments and to achieve high-quality data.

Syllabus

• 1. Introduction into Solid-State NMR spectroscopy: General overview of nuclear interactions with magnetic field; anisotropy of nuclear interactions broadening of NMR spectra in solid state. Basic principles of averaging of anisotropy interactions (Magic Angle Spinning MAS, Dipolar Decoupling DD). Basic differences between solution-state and solid-state NMR spectra (homogeneous and inhomogeneous broadening order vs. disorder). Frictional heating of samples dramatic increase in temperature. 2. Analysis of anisotropy of nuclear interactions techniques of averaging of anisotropy interactions: Detail description of nuclear interactions: chemical shift anisotropy (CSA), dipolar interactions (direct through-space interactions), quadrupolar interactions. Analysis of techniques leading to averaging of the anisotropic interactions: Magic Angle Spinning (MAS), heteronuclear dipolar decoupling (cw, TPPM, XiX), homonuclear dipolar decoupling (WHH-4, BR-24, FSLG, PMLG), double rotation and dynamic angle spinning (DOR, DAS). 3. Techniques of polarization transfer: Heteronuclear (¹H-¹³C, ¹H-X) polarization transfer; increase in sensitivity of NMR experiments cross-polarization (CP); dynamics of CP; Hartmann-Hahn condition influence of MAS speed on the sensitivity and experimental setup. Cross-polarization involving quadrupolar nuclei with half-integer spin higher than . Homonuclear polarization transfer ¹H-¹H spin diffusion (efficient tool to evaluate degree of mixing and size of particles in heterogeneous systems). 4. Spectral editing techniques: Suppression of spinning side-bands (TOSS, SELTICS); suppression of ¹³C NMR signals of carbons with directly bonded hydrogen atoms due to rapid loss of ¹³C coherence (NQS); editing techniques based on different cross-polarization dynamics due to various strength of ¹³C-¹H heteronuclear dipolar couplings in C, CH, CH₂, a CH₃ (CPPI); influence of segmental dynamics; editing techniques based on the evolution of J spin-spin couplings (SoS-APT); manipulation with a spin system (evolution of single-quantum or multiple-quantum coherences). Application on simple and complex systems (e.g. Gly, Ala, simvastatin). 5. Heteronuclear ¹H-X separation experiments (Wide-Line Separation structure and segmental dynamics): Simple separation of 1H-1H dipolar interactions according to ¹³C chemical shifts qualitative evaluation of segmental dynamics; insertion of spin-diffusion period (determination of the size of domains in heterogeneous systems); location of water molecules along polymer chains. Separation of heteronuclear ¹H-¹³C dipolar interactions according to ¹³C chemical shifts quantitative evaluation of segmental dynamics determination of amplitude of reorientation of basic structure units (CH, CH₂). Applications on polymer blends (polyethyleneoxide-polycarbonate), networks (polyimide-polydimethylsiloxane), polypeptides, nanocomposites and inorganic materials. 6. Heteronuclear 1H-X correlation experiments: Through-space correlations induced by dipolar interactions; one-bond correlations; identification of long-range spin-pairs; measurement of interatomic distances (3D HETCOR); comparison with experiments employing indirect spin-spin interactions (sensitivity vs. selectivity, ¹H-¹³C HMQS-J-MAS). Inverse experiments (¹H detected) and gradient selection of coherences. Application on medium-size molecules (simvastatin). 7. Homonuclear ¹H-¹H correlation experiments: Principles and troubleshooting of ¹H-¹H COSY in solid-state NMR (why it is so complicated?) relatively small spectral resolution; spin diffusion instead evolution of J couplings during a mixing period; evaluation of homogeneity and miscibility of mixtures, complexes, aggregates etc. Determination of size of domains and particles in heterogeneous systems; precise measurement of ¹H-¹H interatomic distances. Enhancement of spectral resolution 3D ¹H-¹H-¹³C experiment. Applications on polymer blends (polyethylenoxid-polycarbonate), polymer complexes (polyethyleneoxide-small organic molecules), networks (polyimide-polydimethylsiloxane), nanocomposites, inorganic materials and simvastatin. 8. Double-quantum ¹H-¹H correlation techniques - detection of hydrogen bonds and pi-pi interactions Ultra-fast MAS significant enhancement in spectral resolution (limitation substantial frictional heating of the sample); basic principle of excitation and reconversion of double-quantum coherence (back-to-back BABA sequence). Measurement of ¹H-¹H interatomic distances. 9. Enhancement in spectral resolution X-X a X-Y correlations: INADEQUATE at natural isotopic abundance (medium-size spin systems up to 25-30 carbon atoms; optimization of heteronuclear decoupling transverse dephasing optimized INADEQUATE; DQF-COSY simple modification. Techniques suitable for uniformly labeled samples: ¹³C-¹³C PDSD proton-driven spin diffusion, double-quantum techniques based on recoupling sequences like C7 and PC7. Basic concept of double cross-polarization experiments; suppression of polarization transfer back to 1H spin system Lee-Goldburg decoupling. 10. Backbone and side-chain signal assignment of proteins and polypeptides, determination of global conformation: Basic experimental procedures leading to sequential ¹³C and ¹⁵N signal assignment and subsequent measurement of interatomic distances and torsion angles (polypeptides and small proteins). 2D a 3D techniques for determination of intra-residual spin connectivity C'-C^alpha-C^beta a N-C^alpha-C^beta and inter-residual connectivity C^alpha-C^alpha a N-C^alpha-C^beta. Appropriate selection of mixing period single-quantum or multiple-quantum? What about NOE? Sample preparation. 11. Quadrupolar nuclei: Spectra of quadrupolar nuclei second-order broadening; multiple-quantum two-dimensional techniques partially separating quadrupolar interactions enhancement of spectral resolution; experiments with z-filter; full-echo experiments and other modifications (e.g. fast amplitude modulation FAM); influence of MAS speed, intensity of B₀ and B₁ magnetic fields on quality of the resulting 2D spectra. Correlation experiments involving quadrupolar nuclei (¹H-²⁷Al, 29Si-27Al). Applications on geopolymers and zeolites. 12. Technical aspects of NMR experiments in solid-state: Probehead design temperature ranges and temperature calibration; double-resonance probeheads optimization (wobb) is crucial precondition; triple-resonance probeheads exchangeable insert; setup of magic angle; homogeneity of B₀ field - shimming; power levels of excitations and decoupling fields B₁ minimum repetition delay (duty cycle); linear amplifiers; basic specifications delays, pulses, phases; rotor types limitations and advantages.

Literature

• Melinda J. Duer, Solid-state NMR Spectroscopy: Principles and Applications. Blackwell Science, Oxford, 2002, ISBN 0-632-05351-8.

Assessment methods

oral exam

Language of instruction

Czech

Further comments (probably available only in Czech)

The course is taught once in two years.
Information on the per-term frequency of the course: od 2006/2007.
The course is taught: in blocks.

Teacher's information

http://www.imc.cas.cz/nmr/lect.html

• Enrolment Statistics (Autumn 2008, recent)
  
• Permalink: https://is.muni.cz/course/sci/autumn2008/C8951