Complementary hydrogen bonds and ionic interactions give access to the engineering of organometallic crystals

Abstract

A crystal synthesis strategy based on a sequence of redox/acid–base/self-assembly/crystallisation processes has been devised and successfully applied to prepare a number of mixed organic/organometallic and organometallic/organometallic crystalline materials. An adequate choice of the building blocks permits design and construction of mono-, two- and three-dimensional superanion framework structures encapsulating organometallic cations. The superanions are generated by partial deprotonation of polyprotic acids from the reaction with the organometallic hydroxides [Cr(η⁶-C₆H₆)₂][OH] and [Co(η⁵-C₅H₅)₂][OH], produced in situ by direct oxidation of the neutral complexes [Cr(η⁶-C₆H₆)₂] and [Co(η⁵-C₅H₅)₂]. The anionic superstructures are held together by a combination of neutral and interionic O–H · · · O hydrogen bonds, while the interaction with the organometallic cations is based on a profusion of C–H · · · O bonds reinforced via charge assistance.