Synthesis and Characterization of Self-Assembled Nanoscopic Metallarectangles Capable of Binding Fullerenes with Size-Selective Responses

Abstract

Two new metallarectangles, <b>4</b> and <b>5</b>, were obtained from the self-assembly of areneruthenium-based molecular clips <b>2</b> and <b>3</b> with a new dipyridyl donor ligand <b>1</b> containing a diamide core and ethynyl spacers. The metallarectangles were characterized by multinuclear NMR, electrospray ionization mass spectrometry, and UV–vis spectroscopy, and the molecular structure of <b>4</b> was unambiguously determined by single-crystal X-ray diffraction analysis. Because of the presence of an extended π-electron aromatic surface, the tetracene-containing molecular rectangle <b>5</b> was capable of binding C₆₀ and C₇₀ fullerenes as quantified by UV–vis, emission, and ¹H NMR experiments, providing an example of a supramolecular host capable of recognizing large guest molecules