Infrared Spectra of Alkyldiboranes. III. 1,2-Dimethyl- and 1,2-Diethyldiboranes

Abstract

The infrared spectra of three isotopic variants of 1,2-dimethyldiborane—(CH3B10H2)2, (CH3BH2)2, (CH3BD2)2—and of five 1,2-diethyldiboranes—(C2H5B10H2)2, (C2H5BH2)2, (C2H5BD2)2, (C2D5BH2)2, (C2D5BD2)2—are reported and frequency assignments are made. 1,2-Dialkyldiboranes are very stable with respect to decomposition, but on prolonged standing rearrange to 1,1-dialkyldiboranes. Appearance of absorptions at ca 2100 and 1550 cm—1 is the first indication of the presence of 1,1-dialkyldiborane impurity. Although not conclusive, the evidence favors existence of predominantly cis configurations.