A variable-temperature nuclear magnetic resonance study of complexes of borane and boron trihalides with acetone, diethyl ether, dimethyl ether, n,n-dimethylformamide, methanol, and tetrahydrofuran.

TLDR: In this article, a proton and boron-11 chemical shift and coordination number study of complexes of diborane and the trihalides with dimethyl ether, diethyl ether, methanol, tetrahydrofuran, and to a small extent, acetone and N,N-dimethylformamide has been completed.

Abstract: : A proton and boron-11 chemical shift and coordination number study of complexes of diborane and the boron trihalides with dimethyl ether, diethyl ether, methanol, tetrahydrofuran, and, to a small extent, acetone and N,N-dimethylformamide has been completed. At low temperatures, separate proton resonance signals are observed for bulk solvent and solvent molecules complexed with the boron species. Coordination numbers were measured by the direct integration of the separate signals. The chemical shift separations for bulk and complexed solvent signals decreased in the order BBr3 > BCl3 > BF3 > BH3. An attempt is made to relate these separations to the coordinating abilities of the boron halides. The proton chemical shift data of the bases were correlated with some diborane 11B and 1H nuclear magnetic resonance results to obtain information concerning the species present in the ether-diborane solution. (Author)