| Popis: |
Detailed proton NMR analyses were made on the diboranes, B2H6, CH3B2H5, 1,1-(CH3)2B2H4, 1,2-(CH3)2B2H4, 1,1,2-(CH3)3B2H3, 1,1,2,2-(CH3)4B2H2 and ClB2H5. The bridge hydrogen chemical shift moves −0.40 ppm per methyl group on the diborane molecule and −1.1 ppm with a chlorine substituent. From 11B-decoupled proton spectra long-range homonuclear proton coupling could be observed in the methyl substituted diboranes: J H T −H μ = 7.5—8.7 HZ, J CH μ −H μ = 2.4−3.5HZ, J CH 3 −HT( gem ) =5.0—5.3 HZ, Both the terminal proton (on methyl and chloro diboranes) and the methyl proton chemical shifts are moved significantly upfield with substitution on the far boron atom. |
