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Natural Abundance 17 O‐NMR. Study of Some Macrocyclic Complexes with Alkali Metal Cations
Author(s) -
Popov Alexander I.,
Smetana Alfred J.,
Kintzinger JeanPierre,
Nguyêen Thi ThanhTâam
Publication year - 1980
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19800630315
Subject(s) - chemistry , cryptand , alkali metal , diamagnetism , laser linewidth , nuclear magnetic resonance spectroscopy , inorganic chemistry , relaxation (psychology) , metal , nmr spectra database , chemical shift , spectral line , spectroscopy , ion , stereochemistry , organic chemistry , magnetic field , social psychology , laser , psychology , physics , quantum mechanics , astronomy , optics
Abstract Complexation between crown ethers 12C4, 15C5, 18C6 and cryptand 222, and alkali cations Li + , Na + , K + in various solvents were studied by 17 O‐NMR. spectroscopy. Small diamagnetic shifts arising from the cation electric field are observed. They increase according to the sequence K + < Na + < Li + . 17 O‐linewidth are discussed and compared to the 13 C relaxation times. Linewidth modification results mainly from modifications of the effective correlation time. In general, for crown ethers, considerable line broadening occurs when the cation fits well into the cavity but line narrowing occurs when the cation is much smaller than the cavity.