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Über das fluktuierende Verhalten von triphenylmethylsubstituierten Cyclopentadienyl‐Metallverbindungen
Author(s) -
Kläui Wolfgang,
Werner Helmut
Publication year - 1976
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.19760590314
Subject(s) - cyclopentadienyl complex , chemistry , substituent , ring (chemistry) , sigmatropic reaction , degenerate energy levels , metal , spectroscopy , nuclear magnetic resonance spectroscopy , activation energy , stereochemistry , crystallography , medicinal chemistry , catalysis , organic chemistry , physics , quantum mechanics
The fluxional behaviour of triphenylmethyl substituted cyclopentadienyl metal compounds 1 H‐NMR. spectroscopy has been used to study the influence of the triphenylmethyl substituent on the metallotropic rearrangement in C 5 H 4 (CPh 3 )Si(CH 3 ) 3 and C 5 H 4 (CPh 3 )Sn(CH 3 ) 3 . The most likely mechanism corresponds to a degenerate metal exchange between two neighbouring ring positions. The AA'XX' spectrum of the cyclopentadienyl ring protons in C 5 H 4 (CPh 3 )Sn(CH 3 ) 3 has been analysed under rapid exchange conditions. The free energy of activation for the sigmatropic [1,5]‐Sn shift has been measured by comparison with computer simulated spectra for slow exchange.