Wise Matthew D, Holstein Julian J, Pattison Philip, Besnard Celine, Solari Euro, Scopelliti Rosario, Bricogne Gerard, Severin Kay
Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne , Switzerland . Email:
GZG , Abteilung Kristallographie , Georg-August-Universität Göttingen , Goldschmidtstr. 1 , 37077 Göttingen , Germany.
Chem Sci. 2015 Feb 1;6(2):1004-1010. doi: 10.1039/c4sc03046j. Epub 2014 Nov 11.
Ditopic N-donor ligands with terminal 4-pyridyl groups are omnipresent in coordination-based self-assembly. The utilization of ligands with 3-pyridyl donor groups is significantly less common, because the intrinsic conformational flexibility of these ligands tends to favor the formation of small aggregates. Here, we show that large PdL cages can be obtained by reaction of Pd(ii) salts with metallo-ligands L bearing terminal 3-pyridyl groups. The easy-to-access metallo-ligands contain an Fe(ii) clathrochelate core. These sterically demanding clathrochelate complexes prevent the formation of smaller aggregates, which is observed for less bulky analogous building blocks. The cages were shown to bind BF and BPh anions in aqueous solvent mixtures, whilst the lateral size of the clathrochelate significantly affects their guest encapsulation behavior.
具有末端4-吡啶基的双齿氮供体配体在基于配位的自组装中无处不在。使用具有3-吡啶基供体基团的配体则明显少见得多，因为这些配体固有的构象灵活性往往有利于形成小聚集体。在此，我们表明，通过钯（II）盐与带有末端3-吡啶基的金属配体L反应，可以得到大型的PdL笼。易于获得的金属配体含有一个铁（II）包合螯合物核心。这些空间位阻较大的包合螯合物配合物可防止形成较小的聚集体，而体积较小的类似结构单元则会形成这种小聚集体。结果表明，这些笼子在水性溶剂混合物中能结合BF和BPh阴离子，同时包合螯合物的横向尺寸对其客体包封行为有显著影响。
