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Determination of signs of coupling constants [1J(77Se29Si), 2J(77Se13C), 3J(77Se1H)] in 2,5-dihydro-1,2,5-selenasilaborole derivatives

✍ Scribed by Bernd Wrackmeyer; Roland Köster; Günter Seidel

Publisher
John Wiley and Sons
Year
1995
Tongue
English
Weight
329 KB
Volume
33
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

The signs of coupling constants [1J(^77^Se^29^Si) > 0, ^2^J(^77^Se^13^C~SiMe~) > 0,^3^J(^77^Se^1^H~SiMe~) > 0] were determined for pentaorgano‐substituted 2,5‐dihydro‐1,2,5‐selenasilaboroles [R^3^ = Me, la; R^3^ = C(Me)CH~2~, 1b], and also for derivatives in which the surroundings of the selenium atom were changed by forming a pyridine‐borane adduct (2), by formation of an SeAlCl~3~ adduct (3) and by π‐complexation with the transition metal fragments [Fe(CO)~3~] (4) and [Ru(CO)~3~] (5). The sign determination was achieved by using various types of 2D heteronuclear shift correlations (HETCOR) with ^13^C, ^29^Si or ^1^H detection (HMQC). Some of these experiments had to be modified by z‐filtering or by a Ψ‐BIRD pulse sequence. The change in the magnitude of ^1^J(^13^C^13^C) (la, 58.9 Hz; 4, 33.8 Hz) as a result of π‐complexation follows the trend known for diene complexes.

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