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Carbon‐13, 1 H spin‐spin coupling. V—π‐benzenechromium tricarbonyl and the π‐tropyliumchromium tricarbonyl cation
Author(s) -
Aydin Rafet,
Günther Harald,
Runsink Jan,
Schmickler Hans,
Seel Horst
Publication year - 1980
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270130311
Subject(s) - chemistry , coupling constant , bond length , spin (aerodynamics) , crystallography , resonance (particle physics) , molecular geometry , population , double bond , coupling (piping) , carbon 13 nmr , bond order , crystal structure , stereochemistry , molecule , materials science , atomic physics , organic chemistry , physics , thermodynamics , demography , particle physics , sociology , metallurgy
The 13 C, 1 H spin‐spin coupling constants have been determined for π‐benzenechromium tricarbonyl (3) and the π‐tropyliumchromium tricarbonyl cation using the 13 C{ 2 H}double resonance technique described in a previous paper. In addition, conventional analysis of the 1 H‐coupled 13 C NMR spectrum of 3 was carried out and the 1 H NMR spectrum of 3 partially oriented in the nematic phase was analysed. Both treatments also allowed the determination of the 1 H, 1 H coupling constants for this compound. The n J (CH) results are discussed on the basis of structural data and the theoretical results available. The complexation effects for 1 J (CH) are found to correlate with the CH overlap population and hybridization changes, and those for 3 J (CH) with the CC bond lengths and π‐bond orders. The dependence of 2 J (CH) on CC bond length as well as on the CCH bond angle is indicated. The liquid crystal results are compared with those of related studies.