Title: Endohedral Metallofullerenes: A Unique Host-Guest Association

Speaker: Prof. Josep M. Poblet (Universitat Rovira i Virgili, Spain)

Date/Time: 4:00PM, Jun. 22, 2017(Thur.) 

Location: Room 202, Lujiaxi Building

Abstract:

Kroto, Smalley, Curl and coworkers synthesized C60 and C70 in 1985 by applying the newly available laser technology for the evaporation of graphite. The Krätschmer–Huffman carbon arc process is a more suitable technique that has allowed endohedral metallofullerenes (EMFs) to be prepared in sufficient quantities to obtain structural information by crystallographic and spectroscopic methods and to allow chemical modification. EMFs have attracted much more attention since the synthesis of Sc3N@C80 by Dorn and co-workers in Virginia Tech; the third most abundant fullerene after C60 and C70. During last fifteen years several groups in Japan, USA, China and Europe have developed the synthesis and characterization of this new family of compounds. It is well known that empty fullerenes tend to follow the isolated pentagon rule (IPR), which requires that each of the 12 pentagons is only surrounded by hexagons. During the past decade, many violations to this rule have been reported for endohedral metallofullerenes. Based on the ionic model M3N6+@C2n6- and the orbital energies of the isolated cages, we formulated in 2005 a molecular orbital rule to identify the most suitable hosting cages in metal nitride endohedral fullerenes.Later, the rule was extended to larger fullerenes.2-3 Recently, we have provided physical support to the orbital rule, and we have proposed a general guideline for the structure of endohedral metallofullerenes based on the maximum separation of the twelve pentagons.4 More recently, we have been working in understanding the growth of fullerenes in which non-classical structures containing heptagons appear as intermediates.5,6