Ab initio studies of hydrogen bond formation in methyl cyanide or methyl isocyanide and methanol systems

CH 3 CN ⃛ HOCH 3 and CH 3 NC ⃛ HOCH 3 hydrogen‐bonded systems have been studied theoretically by ab initio MO methods using a 4–31 G basis set at their equilibrium geometries. The stabilization energies of these hydrogen bonds are 5.4 and 5.9 kcal/mol, respectively. The nature of these hydrogen bonds is discussed in the light of frontier orbital theory and the topological properties of the charge density of the chemical bond.