The (2,2′-bipyridine)PtI₂ complex with 5,5′-modification of fluorous side chains: Orthogonal skeleton

Two polyfluorinated PtI₂-containing complexes, [5,5′-bis(R_fCH₂OCH₂)-2,2′-bpy]PtI₂ [R_f = CF₃- (5,5′-3F-PtI₂), HCF₂CF₂- (5,5′-4F-PtI₂)], have been successfully synthesized. Interestingly, these two fluorous Pt-diimine complexes show two different types of structural features. For example, one fluorinated derivative 5,5′-4F-PtI₂ along with 5,5′-3F-PtBr₂, which has been reported before, bear similarity to the C2/c (bpy)MX₂ platform. This simple (bpy)MX₂ platform with C2/c symmetry consists of orthogonal synthons in maintaining the synthons as columns and belts to accompany the introduced fluorous interactions. In contrast, the other fluorinated derivative 5,5′-3F-PtI₂ has been found to be completely different in the solid state. Its pattern of π⋯π interactions is a repetition of three molecular planes with the direction of the columns normal to the molecular planes, and its C3,3′–H⋯I interactions are partially kept though extensively modified. The dimer-monomer units utilize π⋯π stacking along the c-direction and C–H⋯I hydrogen bonds along approximately the b-direction. The less dispersive fluorous components fill in space between the layers of 5,5′-3F-PtI₂ molecules parallel to bc-planes, where weak C–H⋯F interactions are then enabled. Additionally, the electrical properties of 5,5′-3F-PtI₂ and two polymorphic 5,5′-3F-PtBr₂ vs. temperature have been studied. It can be easily seen that the fluorous side chain plays an important role in influencing their molecular packing, which in turn determine their electrical properties.