The B–N Bond in Some Aminoboranes and an Iminoborane,Studied by 11B and 15N NMR Spectroscopy and DFT Methods |
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Authors: | Bernd Wrackmeyer |
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Institution: | Anorganische Chemie II, Universit?t Bayreuth, 95440 Bayreuth, Germany |
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Abstract: | 15N NMR spectra of several aminoboranes (Me2B–NMe2, Cl2B–NMe2, Br2B–NMe2, OCH2CH2OB–NMe2), three N‐pyrrolylboranes, and an iminoborane (tBu–B≡N–tBu) was measured. The spin‐spin coupling constants 1J(15N, 11B) were resolved at elevated temperatures. In the case of the iminoborane at 105 °C, the coupling constant 1J(14N,11B) = 57 Hz could also be determined from the 11B NMR spectrum from 15N NMR 1J(15N,11B) = 81 Hz]. Generally, there is no correlation between the magnitude of 1J(15N,11B) and the bond length dBN. The values 1J(15N,11B) 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. |
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Keywords: | Aminoborane Iminoborane NMR spectroscopy DFT calculations |
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