The properties of some diboron tetrafluoride–tertiary amine adducts
Abstract
Trimethylamine and diboron tetrafluoride form the compounds B2F4(NMe3)2(I) and B2F4NMe3(II) by direct addition. The simple structure Me3N·BF2·BF2·NMe3 for (I) is supported by spectroscopic evidence; uncertain molecular weight values in solution arise from its extreme moisture-sensitivity. Fission of the B–B bond in (I) occurs on pyrolysis at 155 °C to give BF3NMe3, with ethanol at 20 °C to give BF3NMe3, (EtO)3B, and H2, and with hydrogen chloride, where there is indirect evidence for initial formation of (Me3NH)2B2F4Cl2 by addition, the final products being BF2CINMe3 and H2.
The 1 : 1 adduct (II) reacts with triethylamine to give the mixed adduct Et3N·B2F4·NMe3.