Geoffrey Bodenhausen

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It is possible to inhibit the transfer of magnetization in a system with several exchanging sites in dynamic equil., as in a mixt. of cis- and trans-ZrCl4L2 with excess free ligand L (L = (CH3O)3PO). The forward and backward reaction rates involving two selected sites can be studied while the effect of competing exchange processes is quenched. This can be achieved either by selective inversion of the magnetization of the two chosen sites in the reaction interval, or alternatively by inversion of the magneti

The use is described of pattern recognition techniques to analyze folded (in w1) 2-dimensional NMR spectra obtained by using the COSY (correlation spectroscopy) technique. A pattern recognition procedure (P. and B., 1986) relying on the comparison of patterns in z-COSY and anti-z-COSY spectra is applied to both normal and reconstructed spectra of a 1:2 mixt. of the cis and trans isomers of 2-phenylcarboxylic acid Et ester as an illustrative example. [on SciFinder (R)]

The structure of the synthetic peptide CH3CO(Leu-Ser-Leu-Leu-Leu-Ser-Leu)(3)Lys-NH2 in trifluoroethanol/water 60/40 (volume ratio) was characterized by two-dimensional nmr spectroscopy. The peptide, closely related to the amphiphilic helix models designed by W. F. De-Grado and co-workers to mimic protein ion channels [(1988) Science, Vol. 240, p. 1177-1181], folds into a regular helix spanning residues 1-20. Evidence for a helix C-terminal capping conformation, involving the terminal lysine residue, was obs

The effect of exptl. parameters on the sensitivity of 2-dimensional NMR expts. was analyzed. A set of recommendations is provided for maximizing the sensitivity of a given expt. in terms of parameters such as sampling rates, acquisition times, and weighting functions in the 2 dimensions. [on SciFinder (R)]

The generation of nuclear magnetic double quantum echoes and their detection by 2-dimensional Fourier transform spectroscopy is reported for partially aligned 1-deuteron systems in a nematic liq. crystal. Phase-cycling techniques which suppress detection of unwanted coherences were developed, and the transverse decay rates of double quantum coherences agree quant. with relaxation results obtained by more conventional methods. [on SciFinder (R)]

A recently developed approach for the anal. of cross-peak multiplets was applied to 2-dimensional correlation spectra of the binary alkaloid vinblastine and the cyclic undecapeptide cyclosporin A. The exptl. multiplet patterns are encoded in a manner that depends on the topol. of the coupling network but not on the values of the coupling consts. Multiplets that are expected to occur for various possible coupling networks are similarly encoded in a library to allow comparison with exptl. multiplets. The prog

The study of the diffusion of longitudinal scalar order in macromols. in isotropic soln. by 2-dimensional exchange spectroscopy provides addnl. insight into cross-relaxation pathways. [on SciFinder (R)]

The anal. of 2-dimensional NOESY spectra can be misleading if spin diffusion effects are not properly taken into account. An approach consisting in suppressing spin diffusion by selective inversion of the spins undergoing the Overhauser effect, known as QUIET-NOESY (Zwahlen, C. et al., 1994), is described. In addn., the QUIET-EXSY method (Zwahlen, C. et al., 1995), related to the suppression of spin diffusion by QUIET-NOESY, is discussed. [on SciFinder (R)]

Nuclear spin diffusion can be utilized efficiently to gain information on the microscopic homogeneity in disordered solids. Two-dimensional NMR spectroscopy is employed for the measurement of the nuclear spin diffusion. The method is illustrated by comparing 2-dimensional 13C spin diffusion spectra of powder and melt-formed mixts. of adamantane and 2,2,3,3-tetramethylbutane. [on SciFinder (R)]

Several novel methods are introduced that allow one to excite and observe. double- or zero-quantum coherences involving a selected pair of spins. All sequences described employ 270 Deg pulses with Gaussian envelopes, not only for selective excitation, but also for the conversion of single- into double- or zero-quantum coherences and vice versa. Illustrative NMR spectra of trans-2-phenylcyclopropanecarboxylic acid, obtained by using the methods, are presented. [on SciFinder (R)]

Complex overlapping multiplets due to scalar couplings (n)J(C-13, C-13) in fully C-13-enriched molecules can be simplified by polychromatic irradiation of selected spins. The signal intensities of the remaining non-irradiated signals are proportional to th ...

Trains of 2pi or 4pi pulses fail to refocus offsets but can suppress the effects of bilinear interactions such as homonuclear scalar couplings. ...

We present an efficient exptl. method to evaluate whether the effective cross-relaxation rate between a pair of spins vanishes when applying an off-resonance spin-lock field. It is shown that the cross-relaxation rate can be made to vanish even when the two spins concerned resonate at different offsets and experience significantly different tilt angles of their resp. spin-lock fields. This is verified exptl. using a sample of 15N-labeled human ubiquitin, through selective excitation of chosen amide protons.

We report proton spin noise spectra of a hyperpolarized solid sample of commonly used DNP (dynamic nuclear polarization) juice containing TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine N-oxide) and irradiated by a microwave field at a temperature of 1.2K ...

An improved procedure for pattern recognition in 2-dimensional NMR spectra is described. The algorithm uses only the signs of the signals, and begins by searching for responses that are characteristic of 3-spin subsystems, which are then identified as constituent parts of larger N-spin systems. The method relies on the comparison of cross-peak patterns obtained in 2 complementary 2D (2-dimensional) spectra. For the sake of demonstration, a conventional ID spectrum of a mixt. of small mols. is decompd. into

Computer anal. of the multiplet structure of cross peaks in phase-sensitive 2-dimensional NMR correlation spectra allows one to trace out networks of coupled spins, to measure the magnitudes and signs of the scalar coupling consts., and to det. the no. of magnetically equiv. spins at each site. Applications to mixts. of smallmols. show that pattern recognition is feasible even if the signal-to-noise ratio is low, if the multiplets are barely resolved, or if the patterns are partly disguised because of accid

A pulse-repetition rate set to q = 2np radians, i.e., Dfn = n/t, where q = degrees, n = an integer, f = frequency, and t = sec, provides, for a very narrow band of frequencies near the q = 2np conditions, a magnetization vector in which the steps caused by pulses outweigh those caused by precession and which induces a max. NMR signal which is close to the pure absorption-mode condition. Selective excitation by this simple pulse sequence was illustrated by added multiplet subspectra in the Fourier transform

We show that an imbalance between the populations of singlet (S) and triplet (T) states in pairs of magnetically equivalent spins can be generated by dissolution dynamic nudear polarization: In partly deuterated ethanol ((CD3CH2OD)-C-13), this T/S imbalanc ...

A variant of two-dimensional nuclear Overhauser effect spectroscopy (NOESY) is described which allows one to observe cross-relaxation pathways between protons that have heteronuclear scalar couplings to nitrogen-15 or carbon-13 nuclei. In 15N-enriched proteins, it is possible to focus attention on Overhauser effects between amide protons. All Overhauser effects between amide and other protons are eliminated by inserting a bilinear rotation decoupling (BIRD) sequence in the middle of the relaxation interval.

Cross polarization from protons to quadrupolar Li-6 nuclei is combined with dynamic nuclear polarization of protons at 1.2 K and 6.7 T using TEMPOL as a polarizing agent followed by rapid dissolution. Compared to direct Li-6 DNP without cross-polarization, ...

Geoffrey Bodenhausen

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Isolation of selected exchange processes in nuclear magnetic resonance

Folding and pattern recognition in two-dimensional NMR spectra

Lysine as helix C-capping residue in a synthetic peptide

Sensitivity of two-dimensional spectra

Multiple quantum spin-echo spectroscopy

Analysis of multiplets in two-dimensional NMR spectra by topological classification: applications to vinblastine and cyclosporin A

New approaches to the measurement of cross-relaxation rates by two-dimensional NMR

Towards the accurate measurement of internuclear distances in biological macromolecules by suppression of spin diffusion

Direct evidence of microscopic homogeneity in disordered solids

Selective double- and zero-quantum spectroscopy

Homonuclear decoupling for spectral simplification of carbon-13 enriched molecules in solution-state NMR enhanced by dissolution DNP

Quenching homonuclear couplings in magnetic resonance by trains of non-refocusing pulses

Tilt Angle Dependence of Cross-Relaxation in Off-Resonance ROESY

Spin Noise Detection of Nuclear Hyperpolarization at 1.2K

Automated analysis of two-dimensional NMR spectra of mixtures by pattern recognition

Toward automated assignment of nuclear magnetic resonance spectra: pattern recognition in two-dimensional correlation spectra

A simple pulse sequence for selective excitation in Fourier transform NMR

Hyperpolarized para-Ethanol

Measurement of cross-relaxation between amide protons in 15N-enriched proteins with suppression of spin diffusion

Cross polarization from H-1 to quadrupolar Li-6 nuclei for dissolution DNP