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

Abstract

Two polyfluorinated PtI2-containing complexes, [5,5′-bis(RfCH2OCH2)-2,2′-bpy]PtI2 [Rf = 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 CH⋯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 CH⋯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.