Variation of guest selectivity within [Fe₄L₄]⁸⁺ tetrahedral cages through subtle modification of the face-capping ligand

Abstract

We report here the host–guest behaviour of two isoelectronic [Fe₄L₄]⁸⁺ tetrahedral cages that differ only in the nature of their face-capping ligand and possess either triazine (L1) or benzene (L2) cores. Crystallography reveals these hosts to be flexible and adaptable, while NMR spectroscopy shows them to be selective and discriminating in their host–guest behaviour.