1H-NMR for conformation elucidation

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The discussion revolves around the challenges of determining the conformer and assigning H-NMR peaks for N,N-diisopropylacetamidine in CD3CN. The H-NMR spectrum shows various peaks, including a singlet at 5.8 ppm for R-NH, a septet at 4.00 ppm for the CH connected to the N of diisopropylamine, and several singlets at 2.37 ppm and 2.15 ppm. The presence of a doublet at 1.26 ppm indicates methyl groups from the isopropyl groups, while a very broad singlet at -4.9 μ-BHB is also noted. The E conformation is suspected based on theoretical considerations and steric factors, but the NMR data does not provide sufficient justification. The possibility of both E and unfavorable Z conformations existing in solution is suggested, and the poster seeks further insights or additional information that could aid in resolving these ambiguities.
amattiol
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Hello,
I have having some difficulty determining the conformer and assigning H-NMR peaks for a compound with a N,N-diisopropylacetamidine (R-NH-C(CH3)N(2[CH[2(CH3)]])... essentially a diisopropylamine added to CH3CN (ACN). my H-NMR spectrum (at room temp) in CD3CN consists of:
I have assigned all but the singlets

B singlet at 5.8ppm R-NH
B septet at 4.00 CH connected to the N of the diisopropylamine
singlet 2.37
singlet 2.15
TMS at 1.98
doublet at 1.26ppm methyls from the isopropyl
Very B singlet -4.9 μ-BHB

The E conformation is suspected based on theory and steric repulsions, but i cannot justify it from any of the NMR data I have (1H, variable temp 13C, or 11B)

my best guess in regards to those singles is that both E and unfavorable Z conformations exist in solution.

Any help would be greatly appreciated.
 
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