Supramolecular fullerene-porphyrin chemistry. Fullerene complexation by metalated "jaws porphyrin" hosts
Supramolecular fullerene-porphyrin chemistry. Fullerene complexation by metalated "jaws porphyrin" hosts
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DOI：
10.1021/ja017555u
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发表时间：
2002-06-12
影响因子：
15
通讯作者：
Boyd, PDW
中科院分区：
文献类型：
--
作者：
Sun, DY;Tham, FS;Boyd, PDW
卟啉和富勒烯会自发地相互吸引。这种新的超分子识别元件在离散的、可溶的、协调连接的卟啉和金属卟啉中被发现，这些双卟啉中的颚状裂缝是富勒烯客体的有效宿主。得到了Cu -60配合物、游离碱- C-70配合物和吡咯烷衍生物- C-60的x射线结构。C-60Z的富电子6:6环接合键异常接近卟啉或金属卟啉平面。甲苯溶液中的结合常数依次为Fe(II) < Pd(II) < Zn(II) < Mn(II) < Co(II) < Cu(II) < 2H，范围为490 ~ 5200 M-1。出乎意料的是，游离基卟啉与C-60的结合比金属化卟啉更强。这归因于静电力，很大程度上增强了π - π相互作用的范德华力。与金属的排序归因于溶剂化和弱相互作用力的微妙相互作用。关于范德华力、电荷转移、静电吸引和坐标键的相对重要性的相互矛盾的观点得到了解决。这些研究产生的超分子设计原理在制备光物理器件、分子磁体、分子导体和多孔金属有机框架方面具有潜在的应用前景。
Porphyrins and fullerenes are spontaneously attracted to each other. This new supramolecular recognition element is explored in discrete, soluble, coordinatively linked porphyrin and metalloporphyrin climers, Jawlike clefts in these bis-porphyrins are effective hosts for fullerene guests. X-ray structures of the Cu complex with C-60 and free-base complexes with C-70 and a pyrrolidine-derivatized C-60 have been obtained. The electron-rich 6:6 ring-juncture bonds of C-60Z show unusually close approach to the porphyrin or metalloporphyrin plane. Binding constants in toluene solution increase in the order Fe(II) < Pd(II) < Zn(II) < Mn(II) < Co(II) < Cu(II) < 2H and span the range 490-5200 M-1. Unexpectedly, the free-base porphyrin binds C-60 more strongly than the metalated porphyrins. This is ascribed to electrostatic forces, enhancing the largely van der Waals forces of the pi-pi interaction. The ordering with metals is ascribed to a subtle interplay of solvation and weak interaction forces. Conflicting opinions on the relaflve importance of van der Waals forces, charge transfer, electrostatic attraction, and coordinate bonding are addressed. The supramolecular design principles arising from these studies have potential applications in the preparation of photophysical devices, molecular magnets, molecular conductors, and porous metal-organic frameworks.