Liquid- and solid-state (CP-MAS) multinuclear magnetic resonance study of some 2,5-dihydro-1,2,5-oxoniastannaboratoles—carboncarbon coupling constants, 1J(13C13C), in organometallic-substituted alkenes
✍ Scribed by Bernd Wrackmeyer; Klaus Wagner; Angelika Sebald; Lawrence H. Merwin; Roland Boese
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 641 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
Abstract
Derivatives of 2,5‐dihydro‐1,2,5‐oxoniastannaboratoles were studied by multinuclear magnetic resonance both in the liquid (^11^B, ^13^C, ^29^Si, ^119^Sn NMR) and solid state (^13^C, ^29^Si, ^119^Sn CP/MAS NMR). Together with the results of the x‐ray analysis of the 4,5,5‐triethyl‐2,5‐dihydro‐1,2,2‐trimethyl‐3‐phenyl‐1,2,5‐oxoniastannaboratole‐tetrahydrofuran adduct (1‐THF) (space group __P__2~1~/c) the NMR data [chemical shifts and coupling constants J(^119^SnE) (E = ^13^C, ^29^Si, ^119^Sn)] allowed the assessment of structural features in solution and in the solid state (e.g. the weakened coordinative Sn‐O interactions in 1‐THF in solution). The ^1^J(^13^C^13^C) values in 4,5,5‐triethyl‐2,5‐dihydro‐1,2,2‐trimethyl‐3‐trimethylsilyl‐ and ‐3‐trimethylstannyl‐1,2,5‐oxoniastannaboratole and in some non‐cyclic alkenes bearing organometallic substituents were measured using INEPT experiments based on ^3^J(^13^C^1^H) long‐range coupling constants. In the presence of one boryl‐ and two stannyl groups the magnitude of ^1^J(^13^C^13^C) values is reduced to ca. 30 Hz. A positive sign for ^2^J(^119^Sn^117^Sn) in 2‐diethylboryl‐1,1‐bis(trimethylstannyl)but‐1‐ene was determined by 2D ^13^C^1^H and 2D ^119^Sn‐H heteronuclear shift correlations. Scalar ^13^C^11^B and ^119^Sn‐^11^B coupling has been observed for the first time in ^119^Sn CP‐MAS NMR spectra.