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Dr. Luis Echegoyen

University of Texas, El Paso

September 6, 2019 – Fall Seminar

Time and Location: 12 Noon in Meyerhoff Chemistry Building, Room 120

Host: Dr. Zeev Rosenzweig


Fullerene Nanocontainers that Stabilize Unusual Atoms and Clusters Inside

Luis EchegoyenUniversity of Texas at El Paso, 500 Univ. Ave., El Paso Texas, 79968, USA Principal Author’s Principal

For the past two years we have been involved in the synthesis and characterization of new Uranium-based endohedral fullerenes and have obtained X-Ray crystal structures for several of these compounds. Some are mono-uranium species, U@C2n, while some are di-uranium compounds (see structure at the left), U2@C2n.1 Very recently we isolated two new mono-uranium compounds that violate the Isolated Pentagon Rule  (IPR) with a C76 and a C80 cage possessing fused five-membered rings (pentalenes) on their surfaces.2 Still other endohedral structures are much more interesting and totally unanticipated, with formula U2X@C2n, where X= C, O, S or N and 2n= 72, 78 or 80, which reveal interesting metal-cage interactions and totally unprecedented clusters trapped inside. Some of the carbide compounds have been crystallized and the encapsulated U2C cluster (in U=C=U@C80) exhibits unprecedented bonding with totally unanticipated properties (see structure to the right).3

Finally, we have found that bis-porphyrin capsules exhibit exquisitely selective supramolecular binding for several of these uranium-based endohedral fullerene compounds.4

The synthesis, purification and characterization of these interesting endohedral fullerenes will be presented and discussed, along with very recent results about uranium-based endohedrals.