Center for Mass Spectrometry, Department of Chemistry, Chemical Biology, and Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, USA.
J Am Soc Mass Spectrom. 2013 Aug;24(8):1280-7. doi: 10.1007/s13361-013-0671-4. Epub 2013 Jun 19.
In addition to the well-known SO2 loss, there are several additional fragmentation pathways that gas-phase anions derived from N-phenyl benzenesulfonamides and its derivatives undergo upon collisional activation. For example, N-phenyl benzenesulfonamide fragments to form an anilide anion (m/z 92) by a mechanism in which a hydrogen atom from the ortho position of the benzenesulfonamide moiety is specifically transferred to the charge center. Moreover, after the initial SO2 elimination, the product ion formed undergoes primarily, an inter-annular H2 loss to form a carbazolide anion (m/z 166) because the competing intra-annular H2 loss is significantly less energetically favorable. Results from tandem mass spectrometric experiments conducted with deuterium-labeled compounds confirmed that the inter-ring mechanism is the preferred pathway. Furthermore, N-phenyl benzenesulfonamide and its derivatives also undergo a phenyl radical loss to form a radical ion with a mass-to-charge ratio of 155, which is in violation of the so-called "even-electron rule."
除了众所周知的 SO2 损失外，气相中 N- 苯基苯磺酰胺及其衍生物衍生的阴离子在碰撞激活时还会经历几种额外的碎裂途径。例如，N- 苯基苯磺酰胺通过一种机制碎裂形成苯胺阴离子（m/z 92），其中苯磺酰胺部分的邻位上的一个氢原子被特异性地转移到电荷中心。此外，在最初的 SO2 消除后，形成的产物离子主要经历一个环间 H2 损失，形成咔唑啉阴离子（m/z 166），因为竞争的环内 H2 损失在能量上明显不利。用氘标记化合物进行的串联质谱实验结果证实，环间机制是首选途径。此外，N- 苯基苯磺酰胺及其衍生物还会失去一个苯基自由基，形成一个质荷比为 155 的自由基离子，这违反了所谓的“偶数电子规则”。
