Heteronuclear single quantum complex resonance

Fig. 6. H- SN heteronuclear single-quantum coherence (HSQC) spectrum of yeast ubiquitin overexpressed mEscherichia coli cells and purified (1.0mA/, 128 [tl] 1024 [t2] complex points, 64 scans), obtained at the H resonance frequency of 500 MHz. Spectral widths are 1600 and 6250 Hz in Ft and F2, respectively.

Traditionally, homonuclear 2D double quantum filtered correlation spectroscopy (DQF-COSY) and total correlated spectroscopy (TOCSY) spectra are valuable in the identification of resonances of individual monosaccharide units. In the presence of small couplings, through space connectivities detected by NOESY/ROESY (nuclear Overhauser effect spectroscopy/ rotational nuclear Overhauser effect spectroscopy) experiments are also useful in completing the resonance assignment. When the H NMR spectra of complex oligosaccharides are too crowded to fully elucidate the structure by homonuclear correlation methods, it is efficient to use 2D heteronuclear correlation methods, such as heteronuclear single quantum correlation... 

In the presence of excess ammonia, the surface complex coexists with its ammonia adduct ](=SiO)2Ta(=NH)(NH2)(NH3)]. NMR studies on the fuUy N-labeled samples have led to unambiguous discrimination between imido, amido and amino resonances of the surface complex and its NH3 adduct, and [=Si- NH2] through the combination of soHd-state magic-angle spinning(MAS), heteronuclear correlation (HETCOR), 2D proton double-quantum (DQ), singlequantum (SQ) correlation, and 2D proton triple quantum (TQ) single quantum... 

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