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The B–N Bond in Some Aminoboranes and an Iminoborane, Studied by 11 B and 15 N NMR Spectroscopy and DFT Methods
Author(s) -
Wrackmeyer Bernd
Publication year - 2015
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201500653
Subject(s) - chemistry , lone pair , adduct , coupling constant , nuclear magnetic resonance spectroscopy , crystallography , nmr spectra database , carbene , bond length , spectroscopy , stereochemistry , spectral line , molecule , crystal structure , organic chemistry , physics , particle physics , astronomy , catalysis , quantum mechanics
15 N NMR spectra of several aminoboranes (Me 2 B–NMe 2 , Cl 2 B–NMe 2 , Br 2 B–NMe 2 , OCH 2 CH 2 OB–NMe 2 ), three N‐pyrrolylboranes, and an iminoborane ( t Bu–B≡N– t Bu) was measured. The spin‐spin coupling constants 1 J ( 15 N, 11 B) were resolved at elevated temperatures. In the case of the iminoborane at 105 °C, the coupling constant 1 J ( 14 N, 11 B) = 57 Hz could also be determined from the 11 B NMR spectrum [from 15 N NMR 1 J ( 15 N, 11 B) = 81 Hz]. Generally, there is no correlation between the magnitude of 1 J ( 15 N, 11 B) and the bond length d BN . The values 1 J ( 15 N, 11 B) indicate that changes in σ bonding affect their magnitude, and the nature of the lone pair of electrons at nitrogen is of great importance. The calculated NMR parameters of an adduct of the iminoborane with an N‐heterocyclic carbene, show that the bonding situation around the BN double bond in the adduct is comparable with imines.