AbstractA unique example of a bis‐zinc‐porphyrin chemical system in which both macrocycles are covalently connected with a single, short buta‐1,3‐diyne linkage placed at theorthosites of themesophenyl rings is presented. This dimeric compound resulted from an homo‐coupling side‐reaction taking place during a copper‐catalyzed click reaction between an alkyne porphyrin and 2‐azidopyridine derivatives. Its unexpected formation was rationalized by control experiments and an improved synthesis was achieved under copper‐catalyzed Glaser‐Hay coupling reaction conditions. This highly sterically congested bis‐zinc‐porphyrin derivative behaved as a supramolecular host for encapsulating ditopic molecular guests such as 1,4‐diazabicyclo[2.2.2]octane (DABCO) with association constantK1.1in the order of 106 M−1. This value is comparable to current systems that typically feature several connecting linkages between the two zinc‐porphyrin sites resulting in (supra)molecular cages ensuring a high pre‐organization. As such, the requirements to take benefit from supramolecular encapsulation can be reduced to a highly rigid, minimal covalent linkage of four atoms between zinc‐porphyrins as herein described.
摘要 本文介绍了一个独特的双锌卟啉化学体系实例,在该体系中,两个大环均通过位于主题苯基环正反两面的单个短丁基-1,3-二炔链节共价连接。这种二聚化合物是在铜催化的炔卟啉与 2-叠氮吡啶衍生物的点击反应中发生同偶联副反应而产生的。通过对照实验,我们合理地解释了它的意外形成,并在铜催化的格拉塞-海偶联反应条件下实现了改进的合成。这种高度立体拥塞的双锌卟啉衍生物可作为超分子宿主,封装 1,4-二氮杂双环[2.2.2]辛烷(DABCO)等二价分子客体,其关联常数 K1.1 在 106 M-1 数量级。这一数值与当前的系统相当,当前的系统通常在两个锌卟啉位点之间有多个连接链接,从而形成(超)分子笼,确保高度的预组织性。因此,从超分子封装中获益的要求可以降低到如本文所述的锌卟啉之间由四个原子组成的高刚性最小共价连接。