Synthesis of n-dodecylamine borane C12H25NH2BH3, its stability against hydrolysis, and its characterization in THF

Abstract Dihydrogen Hδ+⋅⋅⋅Hδ− bonding that is accepted as an important unconventional hydrogen bonding could play a key role in molecular self-assembly of amine boranes. It is with this goal in mind that we have studied the behavior of n-dodecylamine borane nC12H25NH2BH3 (C12AB) dissolved in anhydrous THF. C12AB can be easily synthesized with a purity higher than 99% by Lewis acid-base reaction of a BH3 complex with n-dodecylamine nC12H25NH2. It is stable when dissolved in THF that is a good solvent of it. However, it is unstable in the presence of moisture, readily hydrolyzing and producing water-soluble borates. Molecular self-assembly of C12AB has thus to be studied in anhydrous conditions, which allows observing by DLS and SAXS-WAXS the formation of core-shell aggregates in anhydrous THF. The aggregates consist of about five self-assembling stretched C12AB molecules where the NH2BH3 groups are in the core of 3 A and the alkyl chains in an outer-shell.