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Zeitschrift für Naturforschung B

A Journal of Chemical Sciences

12 Issues per year


IMPACT FACTOR 2016: 0.631

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1865-7117
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Volume 53, Issue 12 (Dec 1998)

Issues

Determination of Coupling Signs 1J(119Sn, 15N ) and 2J(119Sn, 117Sn) in Trimethylstannylamines

Bernd Wrackmeyer / Jürgen Weidinger / Heinrich Nöth / Wolfgang Storch / Thomas Seifert / Martina Vosteen
Published Online: 2014-06-02 | DOI: https://doi.org/10.1515/znb-1998-1212

The l5N-labelled trimethylstannylamines 1 - 3 [(Me3Sn)3N, (Me3Sn)2NPh, (Me3Sn)2NBCgHi4 (BCgHi4 = 9-borabicyclo[3.3.0]nonyn and the non-labelled 4, Me3Sn-N(BC8Hi4)2 , were prepared and studied by 1H, 1C, 15N and 119Sn NMR. The 15N ultrahigh resolution NMR spectra of 1 revealed otherwise unobserved parameters such as 2J(15N ,Sn ,13C ) and the isotope induced chemical shift 2Δ12/13C(15N). 119Sn NMR spectra of 1, recorded under similar conditions, also show new parameters such as 3J(119Sn,N,Sn,13C) which are not resolved in the non-labelled derivative. By using various types o f two-dimensional heteronuclear shift correlations, absolute coupling signs of 1J(119Sn,15N) (all < 0) in 1 - 3 were determined. By the same techniques it proved possible to confirm the negative sign o f :7(Sn,Sn) (-195.4 Hz) in 1. In contrast, the coupling constants 2J(Sn,Sn) for 2 (+71.7) and 3 (+62.0) possess a positive sign. This sign inversion, observed here for the first time for apparently similar compounds, demonstrates the enormous influence of substituents on the nature of the lone pair of electrons at the nitrogen atom. It also shows that these experiments for sign determinations of coupling constants are necessary in order to interpret these data correctly.

Keywords: Tin; Amines; NM R Data; Ultrahigh Resolution; Coupling Sign Determination

About the article

Received: 1998-07-30

Published Online: 2014-06-02

Published in Print: 1998-12-01


Citation Information: Zeitschrift für Naturforschung B, ISSN (Online) 1865-7117, ISSN (Print) 0932-0776, DOI: https://doi.org/10.1515/znb-1998-1212.

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