Endohedral complex of fullerene C60 with tetrahedrane, C4H4@C60

B3LYP/6–31G(d) hybrid HF/DFT calculations were carried out to determine the structural and electronic properties of the endohedral complex of C60 with tetrahedrane C4H4. It was demonstrated that C4H4 was seated in the center of the C60 cage and existed in a molecular form inside the fullerene. The formation of this complex was endothermic with inclusion energy of 141.05 kcal/mol. C4H4 endohedral doping slightly perturbed the molecular orbitals of C60. The calculated HOMO–LUMO gaps, the electron affinity (EA) and the ionizational potential (IP) indicated that C4H4@C60 seemed to be more kinetically reactive than C60. The IR active modes and harmonic vibrational frequencies of C4H4@C60 were also discussed.