Selective extraction of fullerene C60 by in situ interweaved AgNO3 complex encapsulated C60 molecular cages

Abstract

With an in situ synthesized AgNO3 complex molecular cage, icosahedral C60 can be selectively extracted from fullerene mixture by a facial liquid–liquid interfacial precipitation, resulting in exclusive C60 organometallic microcrystal (C60/C70 = 6/1). By exploiting its intrinsic insolubility against nonpolar solvent, the C60 can be separated from the homologues, C70, which contrarily is assembled through merely hydrophobic interaction and π-π stacking. The AgNO3 complex encaged C60 crystal was morphologically and structurally characterized by SEM, Raman and XRD spectra to revealing the underlying separation mechanism. The selective extraction efficiency (89.7%) was semiquantitatively characterized by combined optical spectroscopy and mass spectrometry, indicating a decent specificity of spontaneously formed molecular cage toward C60 extraction. Thus, this discovery of a template-specific molecular cavity would pave the way to advance molecular imprinting technology using supramolecular array for fullerene separation, prevailing over the conventional “design-synthesis-performance” strategy by substantially reducing the laborious work and economic cost.