Base Strengths of Substituted Tritylamines,N-Alkylanilines, and Tribenzylamine in Aqueous Solution and the Gas Phase: Steric Effects Upon Solvation and Resonance Interactions
作者:Mois�s Canle L.、Ibrahim Demirtas、Antonio Freire、Howard Maskill、Masaaki Mishima
DOI:10.1002/ejoc.200400497
日期:2004.12
due to solvation phenomena as it is absent in the gas phase; for one such compound, TMTrNHCH2CO2Me (4b; pK = 9.30), ΔH⊖ = 17.9 kJ·mol−1 and ΔS⊖ = −118 J·K−1·mol−1. In contrast, the difference in solution base strengths between MeNHAc (pK = −0.56) and TrNHAc (pK = 3.81) is attributed, at least in part, to a reduced base-weakening resonance interaction between the lone pair on N and the acetyl group in
N-三苯甲基乙酰胺 (1h; pK = 3.81) 和 N-苄基-N-甲基-4,4',4''-三甲氧基三苯甲胺 (4i; pK = 9.86) 的共轭酸的解离常数已在乙腈水溶液中测量在 25 °C 和其他温度下测定反应的焓和熵。对于 1h,ΔH⊖ = 40.7 kJ·mol−1 和 ΔS⊖ = 64 J·K−1·mol−1,对于 4i ΔH⊖ = 9.1 kJ·mol−1 和 ΔS⊖ = −159 J·K−1 ·摩尔-1。此外,TrNH2 (1a; 902.1), TrNHPh (1c; 926.3), TrNHAc (1h; 929.7), TrNHC6H4(o-NO2) 在 25 °C 时的气相基础强度(GB 值 kJ·mol-1) (1i; 895.0)、DMTrNH2 (3a; 921.3)、DMTrNHCH2CO2Me (3b; 879.1) 和 DMTrNH(p-NO2Bn) (3d;