The X-ray structures of the 8-substituted-pyrrole tetraarylporphyrin 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetramesitylporphyrin (H2TMOBP), its nickel(I1) complex (NiTMOBP), and the nickel(I1) derivative of 2,3,7,8,12,13,17,18-octabromo-5,10,15,20tetrakis(pentafluoropheny1)porphyrin (NiTPFPOBP.1/2CH2C1z) are reported. The synthesis of the free base H,TPFPOBP is also described. All these molecules are nonplanar, displaying saddle-shaped conformations. The saddle distortions minimize the intramolecular steric interactions between the bromine substituents and the ortho (ortho') carbon atoms or ortho (ortho') substituents of the phenyl rings, and consequently, the corresponding contact distances have similar values in all compounds. Because of the distortion of the porphyrin cores, the cavity defined by the ortho (ortho') substituents gives slightly less steric protection than in the nonbrominated nearly planar ortho-and ortho'-substituted tetraarylporphyrin complexes. Crystallographic data: C56H4sN4Brs (H2TMOBP), tetragonal, space group P42,c, a = b = 15.085 (4) A, c = 14.056 (4) A, V = 3198.8 A', Z = 2, RF = 0.054, RwF = 0.069 based on 638 reflections with I > 3a(10), T = 298 K; NiC56H44N4Brs,1s (NiTMOBP), tetragonal, space group P421c, a = b = 15.024 (3) A, c = 14.068 (6) 1, V = 3175.2 A', Z = 2, RF = 0.049, R w F = 0.057 based on 877 reflections with lo > 2.5u(10), T = 298 K; NiCMN4F2 BrsJ/2CH2C12 (NiTPFPOBP-1/2CH2C1z), monoclinic, space group C2/c, a = 18.105 (3) A, b = 22.141 (5) A, c = 24.301 ( 5 ) 1, B = 93.32 (2)O, V = 9725.5 A', Z = 8, RF = 0.047, RwF = 0.064 based on 2896 reflections with Io > 3a(10), T = 298 K.

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