Synthesis and Characterization of Dihalogenoruthenium(IV)-, Diphenylruthenium(IV)-, and Phenyl-ruthenium(III)-Tetraphenylporphyrin Complexes, Including the Crystal Structure of Ru(TPP)Br2
Ke, Mingzhe, Sishta, C., James, B.R., David Dolphin, Sparapany, J.W., and Ibers, J.A.
Paramagnetic (S = 1) Ru(TPP)X2 (I; TPPH2 = 5,10,15,20-tetraphenylporphyrin; X = Br, Cl, I) are made by treatment of [Ru(TPP)]2 with HBr, HCl, or I2. I (X = Br) crystallizes as tetragonal, space group I4/m, a 13.686(9), c 9.711(7) Å, Z = 2, R = 0.050, Rw = 0.080. The molecule has imposed symmetry 4/m. The porphyrin plane is strictly planar; the Ph rings are perpendicular to this plane, as is the Ru-Br bond. The Ru-Br distance is 2.425(2) Å, the shortest recorded for any Ru-Br bond. 1H NMR isotropic shift data are consistent with π-donation from X-. With PhLi, I (X = Br) yields diamagnetic Ru(TPP)Ph2 (II), which can be thermally decomposed to Ru(TPP)Ph (III); kinetic data imply a stronger Ru-C bond in II compared to the corresponding octaethylporphyrin complex (by 2.6 kcal/mol). A light-induced O2 oxidation of III gives diamagnetic [Ru(TPP)Ph]2O.