The new anionic carbonyl clusters [Ir6(CO)15(HgCl)]− (1) and [Ir6(CO)15[Au(PPh3)]]− (2) have been obtained by reaction of [Ir6(CO)15]2− with HgCl2 or Au(PPh3)Cl in tetrahydrofuran solution. The complexes have been characterized by IR(vco) and NMR studies (13C, 31P, 199Hg) and fast atom bombardment mass spectroscopy. The molecular structures of complexes 1 and 2 have been determined by single-crystal X-ray diffraction. The salt [N(PPh3)2][Ir6(μ3-CO)3(CO)12(μ3-HgCl)]•0.5C6H12 (la) crystallizes in the triclinic space group P1, with unit cell dimensions a = 14.115 (5) Å, b = 14.619 (3) Å, c = 17.762 (5) Å, α = 71.21 (2)°, ß = 66.43 (2)°, γ = 64.61 (2)°, and Z = 2; R = 0.039 and Rw = 0.044 for 4513 observed reflections. The salt [NMe3(CH2Ph)][Ir6(μ-CO)3(CO)12[μ3-Au(PPh3)]]•C4H8O (2a) crystallizes in the triclinic space group P1, with unit cell dimensions a = 13.582 (2) Å, b = 14.513 (2) Å, c = 14.624 (4) Å, α = 110.07 (2)°, ß = 91.75 (2)°, γ = 98.37 (1)°, and Z = 2; R = 0.033 and Rw = 0.043 for 6011 observed reflections. The heptanuclear cluster 1 has an octahedral iridium core, with the mercury atom, which bears a terminally bonded chlorine ligand, capping a triangular face [Ir-Hg average value 2.792 Å, Hg-Cl 2.346 (5) Å]. Two terminal CO groups are bound to each iridium atom, while the three face-bridging carbonyl groups connect vertex-sharing faces. Average distances are Ir-Ir 2.797 Å, Ir-COt 1.86 Å, Ir-COb 2.23 Å (t = terminal, b = bridging). The structural analysis of 2 shows that the AuPPh3 group caps one face of the Ir6 octahedral framework [Ir-Au average 2.838 Å, Au-P 2.272 (3) Å], maintaining the stereogeometry of the CO ligands of the parent metal carbonyl anion [Ir6(CO)16]2− of idealized D3 symmetry. Average distances are Ir-Ir 2.796 Å, Ir-COt 1.87 Å, Ir-COb 2.08 Å. The μ-CO groups in 2 are bent, so to assume a “semitriple” coordination mode. Very little difference in the ligands’ environments is present in the two clusters. © 1991, American Chemical Society. All rights reserved.
Chemistry of Iridium Carbonyl Cluster Complexes. Synthesis and Characterization of Mixed-Metal Carbonyl Clusters via Capping Reactions with HgCI2 and Au(PPh3)CI. Crystal Structures of [N(PPh3)2][Ir6(μ3-CO)3(CO)12(μ3-HgCI)]•0.5C6H12 and [NMe3(CH2Ph)][Ir6(M-CO)3(CO)12[μ3-Au(PPh3)]]-C4H8O
Masciocchi N.;
1991-01-01
Abstract
The new anionic carbonyl clusters [Ir6(CO)15(HgCl)]− (1) and [Ir6(CO)15[Au(PPh3)]]− (2) have been obtained by reaction of [Ir6(CO)15]2− with HgCl2 or Au(PPh3)Cl in tetrahydrofuran solution. The complexes have been characterized by IR(vco) and NMR studies (13C, 31P, 199Hg) and fast atom bombardment mass spectroscopy. The molecular structures of complexes 1 and 2 have been determined by single-crystal X-ray diffraction. The salt [N(PPh3)2][Ir6(μ3-CO)3(CO)12(μ3-HgCl)]•0.5C6H12 (la) crystallizes in the triclinic space group P1, with unit cell dimensions a = 14.115 (5) Å, b = 14.619 (3) Å, c = 17.762 (5) Å, α = 71.21 (2)°, ß = 66.43 (2)°, γ = 64.61 (2)°, and Z = 2; R = 0.039 and Rw = 0.044 for 4513 observed reflections. The salt [NMe3(CH2Ph)][Ir6(μ-CO)3(CO)12[μ3-Au(PPh3)]]•C4H8O (2a) crystallizes in the triclinic space group P1, with unit cell dimensions a = 13.582 (2) Å, b = 14.513 (2) Å, c = 14.624 (4) Å, α = 110.07 (2)°, ß = 91.75 (2)°, γ = 98.37 (1)°, and Z = 2; R = 0.033 and Rw = 0.043 for 6011 observed reflections. The heptanuclear cluster 1 has an octahedral iridium core, with the mercury atom, which bears a terminally bonded chlorine ligand, capping a triangular face [Ir-Hg average value 2.792 Å, Hg-Cl 2.346 (5) Å]. Two terminal CO groups are bound to each iridium atom, while the three face-bridging carbonyl groups connect vertex-sharing faces. Average distances are Ir-Ir 2.797 Å, Ir-COt 1.86 Å, Ir-COb 2.23 Å (t = terminal, b = bridging). The structural analysis of 2 shows that the AuPPh3 group caps one face of the Ir6 octahedral framework [Ir-Au average 2.838 Å, Au-P 2.272 (3) Å], maintaining the stereogeometry of the CO ligands of the parent metal carbonyl anion [Ir6(CO)16]2− of idealized D3 symmetry. Average distances are Ir-Ir 2.796 Å, Ir-COt 1.87 Å, Ir-COb 2.08 Å. The μ-CO groups in 2 are bent, so to assume a “semitriple” coordination mode. Very little difference in the ligands’ environments is present in the two clusters. © 1991, American Chemical Society. All rights reserved.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
