Spectroscopic and theoretical study of the dimeric dicationic fullerene complex [(C70)2]2+ (Ti3Cl13)(-)2

The first spectroscopic characterization of the dimeric dicationic fullerene complex [(C(70))(2)](2+)(Ti(3)Cl(13))(-)(2) is reported and supported by DFT calculations. The IR spectrum of the dimer is interpreted in terms of the normal modes of the pristine C(70), and the effects of charging C(70) and the intercage bond formation between C(70) units on the IR spectrum are discussed. Analysis of the vibrational spectrum of the anion, Ti(3)Cl(13)(-), is also provided. NIR absorption and fluorescence spectra of the complex are studied, and the dimer is shown to have a small HOMO-LUMO gap of 0.8 eV. The electronic structure of [(C(70))(2)](2+) is studied with the use of DFT and compared to that of the other single-bonded fullerene dimers, including [(C(70))(2)](2-), (C(69)N)(2), and [(C(60))(2)](2-). Characteristic features in the vibrational spectra and electronic structure of all single-bonded fullerene dimers are revealed.