Solvatochromism of Heteroaromatic Compounds: XXII. Effect of Bifurcate Hydrogen Bond on the IR Spectrum and Dipole Moment of N-(4-Methyl-2-nitrophenyl)acetamide in Solution

N-(4-Methyl-2-nitrophenyl)acetamide molecule forms a complex with a protophilic solvent, stabilized by a bifurcate H bond and existing in a labile equilibrium with the nonspecifically solvated molecule. The position of the equilibrium is affected by temperature, phase state, and protophilic properties of the medium. Three-centered solvation H complexes of N-(4-methyl-2-nitrophenyl)acetamide are characterized by nonlinear dependence of the NH stretching frequency on the energy of the complex formation and by the positive specific dioxane effect.