Dimerization of 5,10,15,20-tetrakis(6-N-methylquinolinyl)porphyrin in aqueous solutions was studied in the range 274–343 K using absorption and fluorescence spectroscopy. The dimerization equilibrium constant K_D was shown to vary over a wide range as the temperature changed. The enthalpy ΔH^‡ and entropy ΔS^‡ of dimerization in solutions of different ionic strengths were measured. The dimerization was found to be enthalpy driven in all cases. The proposed explanation for the large negative enthalpies of dimerization ΔH^‡ was the optimal overlap of porphyrin macrocycles due to minimization of Coulombic repulsion of ionized peripheral substituents located at large distances from the macrocycle.

使用吸收和荧光光谱研究了5,10,15,20-四（6-N-甲基喹啉基）卟啉在水溶液中的二聚化，范围为274-343K。显示二聚平衡常数K _D随着温度变化而在宽范围内变化。测量在不同离子强度的溶液中二聚化的焓ΔH ^‡和熵ΔS ^‡。发现在所有情况下，二聚化都是焓驱动的。对于二聚化ΔH ^‡的较大负焓，建议的解释是卟啉大环的最佳重叠，这是由于离大环较远的电离的外围取代基的库伦排斥最小。