Structure Determination by 13C-NMR Spectroscopy Using an INADEQUATE Pulse Sequence: Differentiation of Heteroatom- Substituted Organic Constitutional Isomers by means of 13C-13C Coupling Constants
✍ Scribed by Priv.-Doz. Dr. Joachim Buddrus; Dr. Hans Bauer; Prof. Dr. Hans Gotthardt; Rüdiger Jung
- Publisher
- John Wiley and Sons
- Year
- 1983
- Tongue
- English
- Weight
- 218 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0044-8249
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✦ Synopsis
A"
pletely substituted by heteroatoms often presents difficulties. Conventional 13C-NMR spectroscopy certainly provides signals; however, in many cases these cannot be interpreted unambiguously. Here we show that by analyzing the l3C-I3C satellites of a 13C-NMR spectrum the bonding pattern of C atoms can be obtained, thus enabling the different constitutions of such compounds to be distinguished. To measure the satellites the main 13C-NMR signals were reduced in intensity using the double quantum coherence technique (INADEQUATE pulse sequence"]); this method was introduced by Freeman et aZ.['], but previously has been rarely usedr3] to solve constitutional problems.
Chlorination of I-ethoxypentachlorobutadiene leads to formation of pentachloro-3-butenoyl chloride, 1, or pentachloro-2-butenoyl chloride Zr4'. v Cl b C16 Fig. I. Molecular structure of the complex 5 in the crystal. Further details of the crystal structure investigation can be obtained on request from the Fachinformationszentrum Energie Physik Mathematik, D-7514 Eggenstein-Leopoldshafen, by quoting the depository number CSD 50337, the names of the authors, and full citation of the journal.
of nitrogen atoms, is bonded to the carbonyl group via a free electron pair (CS-0-Li: 128.2"). All intramolecular distances appear inconsistent with 5 being formulated as a carbene complex.