Xiaoyuan (Shawn) Chen

Kinetic study of nucleophilic substitution reactions of N-methylimidazole with hemin chloride.

Chen X, Zhang X, Meng Q, Sweigart, DA. Wuji Huaxue Xuebao. 1995; 11 (2): 192-7

Kinetics of the nucleophilic substitution reaction of [Fe(por)Cl]+2N-MeIm®[Fe(por)(N-MeIm)2]+Cl-, where N-methylimidazole is N-MeIm, with hemin chloride [Fe(por)Cl] (por = dianion of protoporphyrin IX (pp) or the corresponding di-Me ester (ppdme)) to give [Fe(por)(N-MeIm)2]+Cl- was studied by means of stopped-flow and visible spectroscopy. The proposed mechanism is as follows: [Fe(por)Cl]+N-MeIm K.dblharw. [Fe(por)(N-MeIm)Cl]; [Fe(por)(N-MeIm)Cl] k1.dblharw.k2 [Fe(por)(N-MeIm)]+Cl-; [Fe(por)(N-MeIm)]+Cl- + N-MeIm k3.dblharw.k4 [Fe(por)(N-MeIm)2]+Cl-. The equil. consts. (K) and rate consts. (k1) were obtained. The std. mol. enthalpy change DrHmq and std. entropy change DrSmq and activation parameters Dr.thermod.Hmq, Dr.thermod.Smq were calcd.