Andreasen Lars V, Lorkovic Ivan M, Richter-Addo George B, Ford Peter C
Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, CA 93106, USA.
Nitric Oxide. 2002 Mar;6(2):228-35. doi: 10.1006/niox.2001.0403.
The reaction of the S-nitrosothiol compound N-acetyl-1-amino-2-methylpropyl-2-thionitrite (RSNO) with the model metalloporphyrin complex Ru(II)(OEP)(CO) (OEP = octaethylporphyrinato dianion) gives the addition product trans-Ru(II)(OEP)(NO)(SR). Here we report the details of a stopped flow kinetics investigation which demonstrates the rapid equilibrium formation of an intermediate concluded to be S-bound RSNO complex Ru(II)(OEP)(RSNO)(CO), which undergoes a rate-limiting step, presumably S-NO bond cleavage to give a second intermediate Ru(III)(OEP)(SR)(CO) too short lived for direct observation. Notably, this is different from the nitrogen coordination pathway often proposed and represents an alternative mechanism by which S-nitrosothiols may be formed or decomposed in the presence of redox active metal centers. Also reported is a brief study of the quantitative photochemistry of RSNO, the photodecomposition of which complicates the kinetics studies by spectroscopic techniques.
S-亚硝基硫醇化合物N-乙酰基-1-氨基-2-甲基丙基-2-硫代亚硝酸盐（RSNO）与模型金属卟啉配合物Ru(II)(OEP)(CO)（OEP = 八乙基卟啉二价阴离子）反应生成加成产物反式-Ru(II)(OEP)(NO)(SR)。在此，我们报告了一项停流动力学研究的详细情况，该研究表明快速平衡形成了一种中间体，推测为硫键合的RSNO配合物Ru(II)(OEP)(RSNO)(CO)，它经历了一个限速步骤，可能是S-NO键断裂，生成了第二个中间体Ru(III)(OEP)(SR)(CO)，其寿命太短无法直接观察到。值得注意的是，这与通常提出的氮配位途径不同，代表了一种在氧化还原活性金属中心存在下S-亚硝基硫醇可能形成或分解的替代机制。还报告了对RSNO定量光化学的简要研究，其光分解使光谱技术的动力学研究变得复杂。
