Thermodynamics of the formation of complexes between aniline derivatives and proton acceptors in solution.

The M-(0), M-(1) and 2(M-(2))(1/2) spectral moments of the nu (NH) bands of aniline derivatives as well as their complexes with various proton accepte rs in solution were determined in the temperature range 285-330K. Studied c ompounds were: aniline; 4-metoxytetrafluoraniline; 2,3,5,6-tetrafluoranilin e and 4-aminotetrafluorpyridine. The coefficients of linear Y=aT+b regressi on of the spectral moments M-(0), M-(1) and 2(M-(2))(1/2) with temperature were determined for the free amino groups as well as for 1:1 complexes with various proton accepters in CCl4 solutions. An analysis of the influence o f temperature on the spectral characteristics of monomers and their 1:1 com plexes with various proton accepters was performed. The heat formation (DeltaH(1)) of the 1:1 complexes with proton accepters w as determined using the dependence of the equilibrium constants on temperat ure. On the basis of the "rule of intensity": -DeltaH = alpha DeltaB(1/2), the DeltaH(2) for the complexes of 1:2 stoichiometry was calculated, allowi ng the estimation of the relation DeltaH(1)/DeltaH(2) (C) 2000 Elsevier Sci ence B.V. All rights reserved.