C5O2 (1,2,3,4-Pentatetraene-1,5-dione), a New Oxide of Carbon

✍ Scribed by Prof. Dr. Günther Maier; Dr. Hans Peter Reisenauer; Dr. Ulrich Schäfer; Prof. Dr. Heinz Balli

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 512 KB
• Volume: 27
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.198805661

✦ Synopsis

two spectra are substracted row by row. One obtains a "spectrum" with the originally unsymmetric components of the cross peaks on both sides of the diagonal but having different signs (Fig. 5b). Figure 7 shows the results of this anti-symmetrization carried out for the spectrum of the nonadecapeptide RO 09-0198.'"1 ri I Fig. 7. NOESY-TOCSY spectrum of Figure 3 after antisymmetrization by combination with a TOCSY-NOESY spectrum (same section as in Fig. 3) recorded under the same conditions. Negative signals are shown in red.

The advantages of the NOESY-TOCSY and TOCSY-NOESY techniques presented here are, above all, an improved signal-to-noise ratio, especially in the case of broad signals, and the possibility of reversing the sequence of transfer steps without loss of sensitivity. The methods of data processing described here facilitate the interpretation of these spectra. The NOESY-TOCSY experiment is primarily attractive for larger molecules, which give rise to strongly negative NOEs and broad lines, owing to short relaxation times.