3,3-dimethyl-1-butene 3,3-二甲基-1-丁烯

Structure: 


IUPAC Name: 3,3-dimethyl-1-butene

Analysis: C₆H₁₂: MW = 84.16


IH NMR


The proton NMR has a singlet representing nine equivalent hydrogens (three -CH₃ groups) and two highly split multiplets in the region  5 - 6 (the alkene region). The singlet strongly suggests the presence of a tert-butyl group (-C(CH₃)₃), while the multiplets suggest a terminal alkene ABC splitting pattern.






...........................................

C13 NMR



















1³C NMR Assignments:
C-13 NMR: q-30.6; s-45.2; d-149.3; t-108.5

The ¹³C spectrum contains four peaks; a quartet at  31, a weak singlet at  45, a doublet at  149 and a triplet at  108. The quartet most likely represents a relatively simple methyl group, bonded to a carbon, and the singlet most likely represents a carbon with no hydrogens, bonded to a mildly electronegative group. The doublet and triplet are in the alkene region; the triplet is somewhat shielded, perhaps due to a steric effect in the ©-position.



.....................................
MASS SPECTRUM





Mass Spectrum Fragments: 
The mass spectrum consists of a molecular ion at 84, and a base peak at m-15 (m/e = 69) which is consistent with loss of a CH₃ group. The spectrum is consistent with a simple molecule which can lose a methyl group to form a stable radical cation.



IR




3400-3200 cm^-1: no OH peak 3100 cm^-1: sharp peak, suggesting unsaturated CH 2900 cm^-1: strong peak suggesting saturated CH 2200 cm^-1: no unsymmetrical triple bonds 1750 cm^-1: no carbonyl 1650 cm^-1: strong peak, suggesting a carbon-carbon double bond