Matrix infrared spectroscopic and theoretical study on the Pt(SF4) and PtF2SF2 complexes with multiple Pt–S bonding characters

Abstract

The reactions of laser-ablated platinum atoms with SF₄ in neon at 4 K resulted in the formation of two complexes, Pt(SF₄) and PtF₂SF₂. Their structures were identified by the specific infrared absorptions as well as isotopic frequency shifts upon ³⁴S substitution and density functional theory calculations. The Pt(SF₄) complex was formed during sample annealing, and was converted to PtF₂SF₂ upon λ > 280 nm irradiation. Density functional theory calculations at the PBE0 level of theory show that both the PtF₂SF₂ and Pt(SF₄) complexes possess singlet ground states. The former possesses a nonplanar C_s symmetry, whereas a geometry with Pt atop SF₄ is obtained for the latter. Geometric and bonding analysis reveal the presence of multiple bonding characters between Pt and S in both the PtF₂SF₂ and Pt(SF₄) complexes, but the PtF₂SF₂ complex exhibits a less polarized S-based σ bond and more polarized Pt-based π bond than Pt(SF₄).