Triphenylphosphine reduction of dioxoosmium(VI) porphyrins. Crystal structures of bis(triphenylphosphine oxide)(octaethylporphinato)osmium(II) and bis(triphenylphosphine)(meso-tetraphenylporphinato)osmium(II)

Abstract

The reactions of OsVI(OEP)O2 and OsVI(TPP)O2 (H2OEP = octaethylporphyrin; H2TPP = meso-tetraphenylporphyrin) with PPh3 in CH2Cl2 yield OsII(OEP)(OPPh3)2 (1) and OsII(TPP)(PPh3)2 (2), respectively. The crystal structures of complexes 1 and 2 have been determined: 1·3H2O, monoclinic, space group P21/c, a = 13.020 (2) Å, b = 14.474 (2) Å, c = 17.988 (3) Å, β = 103.36 (1)°, Z = 2; 2, triclinic, space group P1, a = 11.536 (1) Å, b = 13.445 (1) Å, c = 21.237 (2) Å, α = 85.25 (1)°, β = 75.77 (1)°, γ = 69.55 (1)°, Z = 2. The Os-porphinato unit in 1 is planar within 0.07 Å, with Os-N = 2.029 (8) Å and Os-O(OPPh3) = 2.036 (7) Å. The structure of 2 shows two independent, centrosymmetric molecules with Os-N = 2.044 (3) Å and Os-P = 2.148 (6) Å; the Os-porphinato groups are somewhat puckered, with out-of-plane deviations up to 0.12 Å. The Os-P distances in 2 are substantially longer than normal, reflecting the strong trans influence of PPh3. © 1987 American Chemical Society.