A Reduced-Symmetry Heterobimetallic [PdPtL4 ]4+ Cage: Assembly, Guest Binding, and Stimulus-Induced Switching

Lynn S Lisboa; James A Findlay; L James Wright; Christian G Hartinger; James D Crowley

doi:10.1002/anie.202003220

A Reduced-Symmetry Heterobimetallic [PdPtL₄ ]⁴⁺ Cage: Assembly, Guest Binding, and Stimulus-Induced Switching

Angew Chem Int Ed Engl. 2020 Jun 26;59(27):11101-11107. doi: 10.1002/anie.202003220. Epub 2020 Apr 30.

Authors

Lynn S Lisboa¹, James A Findlay¹, L James Wright², Christian G Hartinger², James D Crowley¹

Affiliations

¹ Department of Chemistry, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.
² School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.

PMID: 32220036
DOI: 10.1002/anie.202003220

Abstract

A strategy is presented that enables the quantitative assembly of a heterobimetallic [PdPtL₄ ]⁴⁺ cage. The presence of two different metal ions (Pd^II and Pt^II ) with differing labilities enables the cage to be opened and closed selectively at one end upon treatment with suitable stimuli. Combining an inert Pt^II tetrapyridylaldehyde complex with a suitably substituted pyridylamine and Pd^II ions led to the assembly of the cage. ¹ H and DOSY NMR spectroscopy and ESI mass spectrometry data were consistent with the quantitative formation of the cage, and the heterobimetallic structure was confirmed using single-crystal X-ray crystallography. The structure of the host-guest adduct with a 2,6-diaminoanthraquinone guest molecule was determined. Addition of N,N'-dimethylaminopyridine (DMAP) resulted in the formation of the open-cage [PtL₄ ]²⁺ compound and [Pd(DMAP)₄ ]²⁺ complex. This process could then be reversed, with the reformation of the cage, upon addition of p-toluenesulfonic acid (TsOH).

Keywords: cages; heterometallic complexes; host-guest systems; metallosupramolecular architectures; stimuli-responsiveness.

Publication types

Research Support, Non-U.S. Gov't