Identification of a Heteroleptic Pd6L6L′6 Coordination Cage by Screening of a Virtual Combinatorial Library

Farzaneh Fadaei Tirani, Suzanne Maria Jansze, Rujin Li, Rosario Scopelliti, Kay Severin, Sylvain Alexandre Marie Sudan
2021
Article

Résumé

The design of structurally defined heteroleptic coordination cages is a challenging task, and only few examples are known to date. Here we describe a selection approach that allowed the identification of a novel hexanuclear Pd cage containing two types of dipyridyl ligands. A virtual combinatorial library of PdnL2n2n complexes was prepared by mixing six different dipyridyl ligands with substoichiometric amounts of Pd(CH3CN)42. Analysis of the equilibrated reaction mixture revealed the preferential formation of a heteroleptic Pd6L6L′612 assembly. The complex was prepared on a preparative scale by a targeted synthesis, and its structure was elucidated by single-crystal X-ray diffraction. It features an unprecedented trigonal-antiprismatic cage structure with two triangular Pd3L3 macrocycles bridged by six L′ ligands. A related but significantly larger Pd6L6L′612 cage was obtained by using metalloligands instead of organic dipyridyl ligands.

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