Bond distances methylamine

The N—O bond distances, found to be 0.133 to 0.139 nm for trimethyl amine oxide (1), are somewhat shorter than the single N—C bond distance of 0.147 nm ia methylamine. The N—C bond distance of 0.154 nm ia trimethyl amine oxide approaches that of the C—C bond. This is ia agreement with the respective absorptions ia the iafrared region valence vibrations of N—O bonds of aUphatic amine oxides are found between 970 920 cm (2). 

Figure 4.24. Potential energy curves for the dissociation a) of the C—N bond in protonated methylamine and b) of the B—N bond in the ammonia-borane adduct. Results of large-scale Cl calculations with all geometric parameters except the bond distance R held fixed (by permission from Michl and BonaCie-Kouteck, 1990).

Methylamine. (a) Bond angles at nitrogen and C—N bond distance. b) The unshared electron pair of nitrogen is a major contributor to the concentration of negative charge indicated by the red region in the electrostatic potential map. 

PROBLEM 6.11 Why is the carbon—nitrogen bond distance in aniline slightly shorter than that in methylamine ... 

Instead of water or HF, one may pair HCOOH with a nitrogen base. The data on the right side of Table 2.37 indicate that the greater basicity of methylamine versus water leads to a stronger H-bond at either SCF or MP2 level of theory. Note, however, that the internuclear distances are comparable. 

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