
TY  - JOUR
A1  - Riggs, NV 
A1  - Radom, L 
T1  - <i>Ab Initio</i> Studies on Amides: Cyanamide, Dicyanamide and Tricyanamide
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1985
VL  - 38
IS  - 6
SP  - 835
EP  - 840
KW  - 
UR  - https://doi.org/10.1071/CH9850835 
N2  - Optimization of the geometry of cyanamide with the 3-21G basis set leads to a planar (C2v) structure, whereas the STO-3G, 6-31G* and 6- 31G** basis sets lead to a pyramidal structure at the amido -nitrogen atom. The 6-31G* and 6-31G** geometries are reasonably close to the experimental geometry, and the calculated barriers to inversion (4.5 and 3.4 kJ mol-1, respectively) are also close to experimental values (5.4-5.6 kJ mol-1), but the STO-3G value (13.9 kJ mol-1) is much too high. Dicyanamide is far from planar at the STO-3G level but planar at the more definitive 6-31G* level, whereas tricyanamide is planar even at the STO-3G level. The prediction is that, in contrast to cyanamide itself, dicyanamide and tricyanamide are planar molecules. Calculated increases in N-C bond-lengths and decreases in C&#8801;N bond-lengths for dicyanamide and tricyanamide as compared with the planar form of cyanamide are used to predict experimental lengths for these bonds in di - and tri- cyanamide. 
ER  -

