Some of our last research works will be presented at the annual meeting of the Small Molecule NMR Conference (SMASH) that will take place in Atlanta (USA) from 7th to 10th September 2014.
- Dr. Teodor Parella is a program Co-Chair.
- Dr. Josep Saurí will give the talk New Methods for the Sign-Sensitive Determination of Homo- and Heteronuclear Coupling Constants in the “Analysis of Chiral Molecules and Related NMR Methods” session.
- Pure In-Phase Heteronuclear Correlation NMR Experiments; Laura Castañar, Josep Saurí, R. Thomas Williamson, Albert Virgili and Teodor Parella.
A general pulse scheme to provide pure in-phase (PIP) multiplets in heteronuclear correlation NMR experiments is presented. The implementation of a zero-quantum filter efficiently suppresses any unwanted anti-phase contributions that usually distort the multiplet pattern of cross-peaks and can hamper their analysis. The clean in-phase pattern obtained in PIP-HSQC and PIP-HSQMBC experiments is suitable for a direct extraction of coupling constants in resolved signals, for a peak-fitting process from a reference signal, or for the application of the IPAP technique in non-resolved multiplets.
- Fast and efficient enantiodifferentiation through pure shift NMR; Laura Castañar, Míriam Pérez-Trujillo, Eva Monteagudo, Lars T. Kuhn, Pau Nolis, Albert Virgili, R. Thomas Williamson and Teodor Parella.
Several NMR enantiodifferentiation studies by using new pure shift (PS) NMR methods will be discussed. First, a frequency-selective 1D HOmodecoupled Band-Selective (HOBS) experiment is proposed for the fast 1H chemical shift discrimination of overlapped signals. On the other hand, the concepts of spectral aliasing (SA) and PS NMR are combined into a novel and robust 2D SAPS-HSQC experiment which provides simultaneous 1H and 13C enantiodifferentiated data with high digital resolution and excellent signal dispersion for both broadband-decoupled 1H and 13C nuclei.
- Perfect-HSQC: Suppression of phase and amplitude JHH modulation; Laura Castañar, Eduard Sistaré, Albert Virgili, R. Thomas Williamson and Teodor Parella.
The amplitude and the phase of cross-peaks in conventional 2D HSQC experiments are modulated by both proton-proton, JHH, and proton-carbon, 1JCH, coupling constants. In this work we shown by spectral simulation and experimentally that JHH interferences can be efficiently suppressed in a novel perfect-HSQC pulse scheme that incorporates JHH-compensated INEPT periods. The improved 2D spectra afford pure in-phase cross-peaks with respect to 1JCH and JCH, irrespective to the experiment delay optimization. In addition, peak volumes are not attenuated by the influence of JHH, rendering practical issues such as phase correction, signal integration and multiplet analysis more accurate.
- Simultaneous measurement of the magnitude and the sign of multiple heteronuclear coupling constants in 19F- or 31P-containing molecules; Josep Saurí, Pau Nolis and Teodor Parella.
A suite of selHSQMBC experiments are presented for the simultaneous measurement of multiple homo- and/or heteronuclear coupling constants from a single 2D cross-peak. A time-shared version allows such determinations for 13C and 15N at the same time and the incorporation of a TOCSY transfer extents its applicability for an entire spin system. The use of non-uniform linear sampling (NUS) and/or the signal detection under homodecoupling conditions will be also evaluated and illustrated with examples.