Infrared Spectra of Trimethylborane-<i>d</i>9 and Triethylborane-<i>d</i>15

Abstract

The infrared spectra of B(CD3)3 and B(C2D5)3 are reported in the 2 to 15 μ range. After minor revisions of a previous frequency assignment for B(CH3)3, the force constants obtained from a modified valence force treatment of B(CH3)3 have been used to calculate and assign the frequencies of B(CD3)3. This assignment is consistent with frequency values predicted from a study of other methyl-deuterated compounds. Agreement with the Teller-Redlich product rule is fair. An interesting and perhaps unexpected feature is the upward shift of the B–C asymmetric stretching frequency upon deuteration; the correctness of the assignment of that vibration was verified by use of B10(CD3)3. In the latter part of this article, the observed bands of B(C2D5)3 are assigned.