Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
Nat Chem. 2010 Sep;2(9):780-3. doi: 10.1038/nchem.742. Epub 2010 Jul 25.
Many molecular cages selectively bind guests in solution, but in the solid state close packing often prevents guest entry, which renders the cages inactive. We envisioned that coordination networks constructed from well-known molecular cages could transfer the richness of solution-state host-guest chemistry into the solid state. We report a crystalline coordination network generated from an infinite array of octahedral M(6)L(4) cage subunits (M = metal, L = ligand). This coordination network is a 'crystalline molecular sponge' engineered on the molecular level and retains similar guest recognition properties to those found in solution. The network crystallinity is robust and thus X-ray diffraction analysis can be used to unambiguously observe single-crystal to single-crystal guest inclusion. The void spaces define alternating M(12)L(8) and M(12)L(24) cuboctahedral molecular cages and these large cages absorb up to 35 weight per cent of C(60) or C(70) by simply soaking the crystals in a toluene solution of the fullerene. When the crystals are immersed in fullerene mixtures, C(70) is preferentially absorbed.
许多分子笼在溶液中选择性地结合客体，但在固态中，由于紧密堆积常常阻止客体进入，从而使笼失去活性。我们设想，由众所周知的分子笼构建的配位网络可以将溶液态主客体化学的丰富性转化到固态中。我们报道了一种由无限排列的八面体 M(6)L(4)笼亚基（M = 金属，L = 配体）生成的结晶配位网络。这种配位网络是在分子水平上设计的“结晶分子海绵”，并保留了与溶液中相似的客体识别特性。网络结晶度很稳定，因此可以使用 X 射线衍射分析来明确地观察单晶到单晶的客体包容。空隙空间定义了交替的 M(12)L(8)和 M(12)L(24) 立方八面体分子笼，这些大笼通过简单地将晶体浸泡在富勒烯的甲苯溶液中，可吸收高达 35 重量%的 C(60)或 C(70)。当晶体浸入富勒烯混合物中时，优先吸收 C(70)。
