Theoretical Study on the Electronic Structure and Geometry of BTTTF-C60

The geometry, electronic structure and frontier orbitals of bis-thinenyl-tetrathiafulvalene-C60(BTTTF-C60) and Tetrathiafulvalene-C60(TTF-C60) have been calculated by AM1 method. The results indicate that the geometries of BTTTF-C60 andTTF-C60 are curved. The curved geometry conformation is probably caused by the charge interaction between C60 and TTF, C60 and BTTTF respectively. Because the LUMO energy of C60 is close to the HOMO energy of BTTTF, the D-A reaction to BTTTF-C60 takes place easily. The LUMO energies in BTTTF-C60 and TTF-C60 are low and their orbitals distribution is mainly shown in C60 section, which means C60 section can still accept electrons. The analyses of charge population and molecular orbitals distribution, the property of BTTTF-C60 is similar to TTF-C60. A charge-separated state may occur in BTTTF-C60 when it is excited.