Fullertubes: Cylindrical Carbon with Half-Fullerene End-Caps and Tubular Graphene Belts, Their Chemical Enrichment, Crystallography of Pristine C90-D5h(1) and C100-D5d(1) Fullertubes, and Isolation of C108, C120, C132, and C156 Cages of Unknown Structures

We report a chemical separation method to isolate fullertubes: a new and soluble allotrope of carbon whose structure merges nanotube, graphene, and fullerene subunits. Fullertubes possess single-walled carbon nanotube belts resembling a rolled graphene midsection, but with half-fullerene end-caps. Unlike nanotubes, fullertubes are reproducible in structure, possess a defined molecular weight, and are soluble in pristine form. The high reactivity of amines with spheroidal fullerene cages enables their removal and allows a facile isolation of C-96-D-3d(3), C-90-D-5h(1), and C-100-D-5d(1) fullertubes. A nonchromatographic step (Stage 1) uses a selective reaction of carbon cages with aminopropanol to permit a highly enriched sample of fullertubes. Spheroidal fullerenes are reacted and removed by attaching water-soluble groups onto their cage surfaces. With this enriched (100-1000 times) fullertube mixture, Stage 2 becomes a simple HPLC collection with a single column. This two-stage separation approach permits fullertubes in scalable quantities. Characterization of purified C-100-D-5d(1) fullertubes is done with samples isolated in pristine and unf unctionalized form. Surprisingly, C-60 and C-100-D-5d(1) are both purplish in solution. For X-ray crystallographic analysis, we used decapyrrylcorannulene (DPC). Isomerically purified C-90 and C-100 fullertubes were mixed with DPC to obtain black cocrystals of 2DPC{C-90-D-5h(1)}center dot 4(toluene) and 2DPC{C-100-D-5d(1)}center dot 4(toluene), respectively. A serendipitous outcome of this chemical separation approach is the enrichment and purification of several unreported larger carbon species, e.g., C-120, C-132, and C-156. Isolation of these higher cage species represents a significant advance in the unknown experimental arena of C-100-C-200 structures. Our findings represent seminal experimental evidence for the existence of two mathematically predicted families of fullertubes: one family with an axial hexagon with the other series based on an axial pentagon ring. Fullertubes have been predicted theoretically, and herein is their experimental evidence, isolation, and initial characterization.