Terpyridine (tpy)-based coordination-driven self-assembly has been widely applied in the construction of 2D and 3D metallo-supramolecules during the past few years. However, the introduction of multiple types of metal ions into one structure, especially giant supramolecular architectures have rarely been reported. We herein studied the stepwise self-assembly of hexagonal macrocyclic supramolecule using tpy-based ligand. The Ru(II)-tpy ligand first self-assembled with one equivalent of Fe(II), forming the first cycle in almost quantitative yield through intramolecular complexation, and subsequent addition of two equivalent of Zn(II) for intermolecular complexation led to the construction of the final hexagonal architecture. Both electrospray ionization-mass spectrometry (ESI-MS), traveling wave ion mobility-mass spectrometry (TWIM-MS), as well as multidimensional NMR spectroscopy confirmed that Fe(II) selectively coordinated at the specific site during the first stage, and the final self-assembled product was also characterized via the above-mentioned techniques. Moreover, the supramolecules were directly visualized with atomic resolution under ultra-high vacuum-low temperature-scanning tunneling microscopy (UHV-LT-STM), and the different metal atoms were identified according to the HOMO-LUMO band gap obtained from <i>dI/dV</i> spectrum with the tip positioned on each metal atom.

Self-assembly of macrocyclic supramolecule with multiple types of metal ions and characterization by STM

2019 Spring National Meeting

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