The structural, electronic and spectroscopic properties of monomer FPt (2-(4′,6′-difluorophenyl)pyridinato-N,C2′)(2,4-pentanedionato-O,O) (1) and dimer [FPt]2 (2) were explored within the density functional theory (DFT) and time-dependent DFT (TD-DFT). The calculated geometry parameters and spectroscopic results agree well with the experimental observation. In the ground state, FPt exists in the form of monomer, while in the excited state, dimer [FPt]2 forms with a Pt-Pt contraction of 0.05 nm due to the promotion of σ[dz2(Pt2)] to π*(phenylryridyl) and σ[pz(Pt2)]. Transition properties of monomer and excimer are different in nature: the former originates from mixed transitions of 3MLCT and 3ILCT, while the latter is dominated by 3MMLCT transition.
