Crystal structures of meso-tetrakis(2′,6′/3′,5′-difluorophenyl)porphyrins and their metal complexes: Influence of position of the fluoro groups on their structural properties

Two series of non-solvated structures of 5,10,15,20-tetrakis(2′,6′/3′,5′-difluorophenyl)porphyrins, H2T(2′,6′/3′,5′-DFP)P and their metal (Cu(II) and Zn(II)) complexes were determined by single crystal XRD. H2(2′,6′-DFP)P, 1 and its metal (Cu(II), 2 and Zn(II), 3) complexes showed near planar geometry of the porphyrin ring with the maximum root-mean-square (r.m.s.) which is the average deviation of the 24 core atoms from their least-squares plane by 0.056(3) Å while MT(3′,5′-DFP)P (Cu(II), 4 and Zn(II), 5) structures feature significant distortion of the macrocycle (r.m.s. = 0.22(2) Å). Nearly planar structures 1-3 revealed more number of intermolecular short contacts than that observed in nonplanar structures 4 and 5. Normal coordinate structure decomposition analysis of the structures 1-3 revealed negligible wave distortion of the macrocycle but the corresponding nonplanar 4 and 5 structures feature mainly ruffled combined with minimal saddled distortions. The increased nonplanarity of the less sterically hindered derivatives 4 and 5 has been ascribed to intermolecular interactions and/or crystal packing forces.