Expanding the world of endohedral fullerenes -: The Tm3N@C2n (39≤n≤43) clusterfullerene family

A new family of endohedral fullerenes, based on an encaged trithulium nitride (Tm3N) cluster, was synthesised, isolated and characterised by HPLC, mass spectrometry, and visible-NIR and FTIR spectroscopy. Tm3N clusterfullerenes with cages as small as C-76 and as large as C-88 were prepared and six of them were isolated. Tm3N@C-78 is a small clusterfullerene. The two isomers of Tm3N@C-80 (I and II) were the most abundant structures in the fullerene soot. Tm3N@C-82, Tm3N@C-84, and Tm3N@C-86 represent a new series of higher clusterfullerenes. All six isolated Tm3N clusterfullerenes were classified as large energy-gap structures with optical energy gaps between similar to1.2 and similar to1.75 eV. Tm3N@C-80 (I) and Tm3N@C-80 (II) were assigned to the C-80 cages C-80:7 (I-h) and C-80:6 (D-5h). For Tm3N@C-78, the analysis pointed to an elliptical carbon cage with C-78:1 (D-3) or C-78:4 (D-3h) being the probable structures.