In order to provide insight into the reaction pathways of nitrogen oxide redox species with [Fe–S] models that may parallel those existing in biology, the reactivity of the iron-sulfur species, [FeII(S4NEt2N)]}2 (1) and [FeII(CH3CN)(S4NEt2N)] (2), where (S4NEt2N)2− = 2,6-bis(2-mercaptophenylthiomethyl)-4-diethylaminopyridine(2−), towards NO+ (nitrosation) has been studied mechanistically in acetonitrile and compared with the corresponding reactions with NO (nitrosylation). For the nitrosation of 1, the reaction takes place in two steps that correspond to the nitrosation of the mononuclear (2) and dinuclear (1) complexes, respectively. For the corresponding carbonyl complex [FeII(CO)(S4NEt2N)] (3), the nitrosation reaction occurs in a single step. The relative reactivity of the iron-sulfur species is approximately (1)/(2)/(3) = 1/20/10. Activation parameters for the nitrosation of 1 (ΔH# = 27 ± 1 kJ mol−1, ΔS# = −111 ± 2 J K−1 mol−1, and ΔV# = −19 ± 2 cm3 mol−1), 2 (ΔH# = 46 ± 2 kJ mol−1, ΔS# = −22 ± 7 J K−1 mol−1, and ΔV# = −9.7 ± 0.4 cm3 mol−1) and 3 (ΔH# = 38 ± 1 kJ mol−1, ΔS# = −44 ± 4 J K−1 mol−1, and ΔV# = −7.8 ± 0.3 cm3 mol−1) were determined from variable temperature and pressure studies. The significantly negative ΔS# and ΔV# values found for the nitrosation reactions are consistent with an associative mechanism. A comparative study of the reactivity of the iron-sulfur species 1 to 3 towards NO+ and NO is presented.
为了深入了解氮氧化物氧化还原物种与[Fe-S]模型的反应途径(可能与
生物学中存在的反应途径相似),研究了
铁硫物种 [FeII(S4NEt2N)]}2 (1) 和 [FeII(CH3CN)(S4NEt2N)] (2)的反应性、其中 (S4NEt2N)2- = 2,6-双(2-巯基苯
硫甲基)-4-
二乙基氨基吡啶(2-),在
乙腈中对 NO+(
亚硝酸化)进行了机理研究,并与 NO(
亚硝酸化)的相应反应进行了比较。1 的亚硝基化反应分为两个步骤,分别对应于单核(2)和双核(1)络合物的亚硝基化反应。对于相应的羰基络合物 [FeII(CO)(S4NEt2N)] (3),亚硝基化反应只发生了一步。
铁硫物种的相对反应活性大约为 (1)/(2)/(3) = 1/20/10。1 (ΔH# = 27 ± 1 kJ mol-1,ΔS# = -111 ± 2 J K-1 mol-1,ΔV# = -19 ± 2 cm3 mol-1)、2 (ΔH# = 46 ± 2 kJ mol-1,ΔS# = -22 ± 7 J K-1 mol-1,ΔV# = -9.7 ± 0.4 cm3 mol-1)和 3(ΔH# = 38 ± 1 kJ mol-1,ΔS# = -44 ± 4 J K-1 mol-1,ΔV# = -7.8 ± 0.3 cm3 mol-1)是通过变温和变压研究确定的。亚硝化反应的 ΔS# 和 ΔV# 值明显为负值,这与关联机理一致。本文对
铁硫物种 1 至 3 对 NO+ 和 NO 的反应性进行了比较研究。