Holloway Lauren R, McGarraugh Hannah H, Young Michael C, Sontising Watit, Beran Gregory J O, Hooley Richard J
University of California - Riverside , Department of Chemistry and the UCR Center for Catalysis , Riverside , CA 92521 , USA . Email:
Chem Sci. 2016 Jul 1;7(7):4423-4427. doi: 10.1039/c6sc01038e. Epub 2016 Mar 29.
Ligand centered reactions are capable of conferring structural switching between a metastable, self-assembled Fe-iminopyridine aggregate and a stable ML helicate. The reactivity is directed and accelerated by the stability of the final product structure. Under aerobic conditions, both substitution and oxidation occurs at the ligand, exploiting atmospheric oxygen as the oxidant. In the absence of air, reaction occurs more slowly, forming the less stable substitution product. Control ligands show a preference for simple substitution, but the self-assembly directs both substitution and oxidation. The metastable nature of the initial aggregate species is essential for the reaction: while the aggregate is "primed" for reaction, other analogous helicate structures are "locked" by self-assembly, preventing reactivity.
以配体为中心的反应能够在亚稳态的自组装铁-亚氨基吡啶聚集体和稳定的ML螺旋配合物之间实现结构转换。反应活性由最终产物结构的稳定性引导并加速。在有氧条件下，配体上会发生取代和氧化反应，利用大气中的氧气作为氧化剂。在没有空气的情况下，反应进行得较慢，形成较不稳定的取代产物。对照配体表现出对简单取代的偏好，但自组装过程同时引导取代和氧化反应。初始聚集体物种的亚稳态性质对反应至关重要：虽然聚集体为反应“做好了准备”，但其他类似的螺旋配合物结构通过自组装被“锁定”，从而阻止了反应活性。
