Aryldiazo Complexes. Synthesis and Structure of a Five-Coordinate Complex Possessing a “Half Doubly Bent” Aryldiazo Ligand and an Intermediate Coordination Geometry[IrCl(N₂C₆H₅)P(CH₃(C₆H₅)₂)₃][PF₆]

The complex [IrCl(N₂C₆H₅)(P(CH₃)(C₆H₅)₂)] [PF₆] has been prepared with the specific intent of inducing the aryldiazo ligand into a geometry intermediate between the previously observed singly and doubly bent geometries. This has been accomplished by employing ligands of intermediate bulk (P(CH₃)(C₆H₅)₂) to distort the coordination geometry of the Ir atom from its electronically favored geometry. The structure of this iridium-aryldiazo complex has been determined crystallographically and consists of discrete cations and anions. The cation is five-coordinate with a highly distorted geometry about the metal which cannot be adequately described by any idealized geometry. The intermediate coordination geometry about the iridium atom is mirrored by the geometry of the aryldiazo ligand which is intermediate between singly and doubly bent. Some relevant metrical parameters are: Ir-N(1), 1.835 (8)Å; N(1)-N(2), 1.241 (11) Å; N(2)-C(11), 1.421 (11) Å; Ir-N(1)-N(2), 155.2 (7)°; N(1)-N(2)-C(111), 118.8 (8)°. The hexafluorophosphate anion is disordered. The compound crystallizes from acetone in space group C₂²-P2₁ with a = 15.767 (7) Å,b= 15.583 (7) Å, c = 9.002 (4) Å, β = 91.67 (2)°, and Z = 2. The pseudo-mirror-symmetry of the cation caused great difficulty in the solution of the structure, as it was very difficult to differentiate the correct atomic positions from the mirror-related images. The correct solution was obtained by excluding those solutions which resulted in highly irregular bond angles and distances and in unreasonably short nonbonded contacts. Based on 7134 reflections with F_o²≥ 3σ{F_o²), the structural data were refined by full-matrix, least-squares methods to R indices of R = 0.046 and R_w= 0.072. The synthesis, spectra, and reaction chemistry of the complex are discussed.