Indirect Nuclear Spin-Spin Coupling Constants

Indirect nuclear spin-spin coupling constants J(11B,1H) and J(11B, 11B) in neutral and anionic boron hydrides 1 – 17, calculated at the B3LYP/6-311+G(d,p) level of theory, are in good agreement with experimental data if available. This is shown for [BH4]− (1), B2H6 (2), B4H10 (3), B5H9 (4), or [B2H7]− (12). The calculations can be used to obtain values for those coupling constants for which experimental information is hardly accessible. This applies to complex spin systems involving the quadrupolar 11B nuclei such as in [B6H6]2−(11), to fast dynamic processes such as in B6H10 (5), [B5H8]− (10), [B6H7]− (11-H), [B3H8]− (13), Be(BH4)2 (14), (η-C5H5)BeBH4 (15), Be(B3H8)2 (16), Me2AlB3H8 (17), or to instable species such as [B2H6]2− (6), B2H4 (7), B3H7 (8), and B4H8 (9). The experimental 11B NMR spectrum reported in the literature for the dianion 6 does not resemble the spectrum predicted on the basis of the calculated coupling constants.