Cycloparaphenylenes (CPPs), commonly referred to as carbon nanorings, feature a remarkable structure consisting of cyclically linked para-benzene units ranging in size from 5 units, to 12 and beyond. In recent years due to CPP's being the smallest unit structure of carbon nanotubes (CNTs), and having unique and unexplored properties, CPPs have attracted much attention from chemists and materials scientists. Modification of the CPP ring can change the HOMO-LUMO band gap, absorption, and emission properties.1) Recent research has demonstrated key breakthroughs in CPP research including, functionalization of CPPs,2) and a bottom-up total synthesis of carbon nanotubes from CPPs have been reported.3) Additionally, CPPs can function as supramolecular hosts for iodine4) and fullerene5) in the ring pore have also been reported.
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