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Isotope‐induced chemical shifts 1 Δ 12/13 C( 29 Si) and 57 Fe NMR of organosubstituted 2,5‐dihydro‐1,2,5‐azasilaboroles, a silole and their tricarbonyliron complexes †
Author(s) -
Wrackmeyer Bernd,
Seidel Günter,
Köster Roland
Publication year - 2000
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/1097-458x(200007)38:7<520::aid-mrc681>3.0.co;2-a
Subject(s) - chemistry , chemical shift , carbon 13 nmr , stereochemistry
2,5‐Dihydro‐1,2,5‐azasilaboroles ( 1 ) (cyclic heterodienes) readily form tricarbonyliron complexes ( 3 ) and both are compared with a silole ( 2 ) and its tricarbonyliron complex ( 4 ). The compounds 1–4 were studied with respect to isotope‐induced chemical shifts 1 Δ 12/13 C( 29 Si). The data set indicates that the interpretation of 1 Δ 12/13 C( 29 Si) is not straightforward. Although there may be a crude correlation between 1 Δ 12/13 C( 29 Si) and the magnitude of | 1 J ( 29 Si, 13 C| within each class of compounds [e.g., in the series Me 4 − n Si(CCMe) n ( n = 0, 1, 2, 3, 4)], a direct relationship between different classes is not apparent, even for different Me groups linked to the same silicon atom ( 3 , 4 ). 57 Fe NMR (16.2 MHz) measurements are reported for the first time, using standard NMR equipment and ca 0.5 M solutions in 5 mm tubes. The 57 Fe nuclear shielding in the heterodiene complexes is reduced by 500–600 ppm with respect to that of the silole complex (δ 57 Fe = +241.2). Copyright © 2000 John Wiley & Sons, Ltd.