[60]Fullerene metal complexes with large effective two-photon absorption cross-section

Abstract

Fourteen novel complexes of fullerene C₆₀ with metal dialkyldithiophosphate, {[(RO)₂PS₂]₂M}·2C₆₀ (R = Me and Et; M = Mn, Fe, Co, Ni, Cu, Zn and Pd), can be obtained in high yield by the reaction of metal(II) dialkyldithiophosphate complexes with C₆₀ fullerene. Their structures are determined by ¹H, ¹³C, and ³¹P NMR spectroscopy, elemental analysis, FT-IR and UV-vis, and are supplied by single crystal X-ray data. The compound {[(EtO)₂PS₂]₂Pd}·2C₆₀ was also studied by the HRTEM image and SAED patterns. Studies of the optical properties of the complexes of fullerene C₆₀ with metal dialkyldithiophosphate show that these compounds all have very strong nonlinear optical absorption effects. The nonlinear absorption of fourteen complexes of fullerene C₆₀ with metal dialkyldithiophosphate (in o-dichlorobenzene and in the solid state) was measured by the open-aperture Z-scan technique at a wavelength of 532 nm. DFT calculations are also used to discuss the stability of these complexes and to confirm the structural assignments.