Multivalency in the gas phase: H/D exchange reactions unravel the dynamic "rock 'n' roll" motion in dendrimer-dendrimer complexes.
Multivalency in the gas phase: H/D exchange reactions unravel the dynamic "rock 'n' roll" motion in dendrimer-dendrimer complexes.
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DOI：
10.1002/chem.201301951
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发表时间：
2013-10
期刊：
影响因子：
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通讯作者：
Zhenhui Qi;Christoph Schlaich;C. Schalley
中科院分区：
文献类型：
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作者：
Zhenhui Qi;Christoph Schlaich;C. Schalley
通过电喷雾电离部分质子化的氨基封端的聚丙烯胺（POPAM）和在所有分支上用苯并[21]冠-7完全官能化的POPAM树枝状聚合物，成功地电离了非共价树枝状聚合物-树枝状聚合物复合物。氢/氘交换（HDX）的实验进行树枝状聚合物-树枝状聚合物复合物在高真空的质谱仪引起的所有不稳定的NH氢原子的完全交换。由于冠醚代表非共价保护基团，防止它们所配位的铵基团上的HDX反应，因此该结果为非常动态的结合情况提供了证据：每个冠醚具有足够的移动的，可以从一个铵结合位点移动到另一个。从示意图上看，人们可以将这种运动与两个摇滚舞者进行比较，这两个舞者在任何时候都不会完全失去联系。虽然多价连接确实增加了整体亲和力，但单个位点结合和解离的“微观动力学”仍然很快。
Noncovalent dendrimer-dendrimer complexes were successfully ionized by electrospray ionization of partly protonated amino-terminated polypropylene amine (POPAM) and POPAM dendrimers fully functionalized with benzo[21]crown-7 on all branches. Hydrogen/deuterium exchange (HDX) experiments conducted on dendrimer-dendrimer complexes in the high vacuum of a mass spectrometer give rise to a complete exchange of all labile NH hydrogen atoms. As crown ethers represent noncovalent protective groups against HDX reactions on the ammonium group to which they are coordinated, this result provides evidence for a very dynamic binding situation: each crown is mobile enough to move from one ammonium binding site to another. Schematically, one might compare this motion with two rock 'n' roll dancers that swirl around each other without completely losing all contact at any time. Although the multivalent attachment certainly increases the overall affinity, the "microdynamics" of individual site binding and dissociation remains fast.