Synthesis and structure of ammine and amido complexes of iridium

The reaction of (NH4)(2)[IrCl6] with NH4Cl at 300 degrees C in a sealed gla ss ampoule yields the iridium(III) ammine complex (NH4)(2)[Ir(NH3)Cl-5], wh ich crystallizes isotypically with K-2[Ir(NH3)Cl-5] in the orthorhombic spa ce group Pnma with Z = 4, and a = 1350.0(2); b = 1028.5(3); c = 689.6(2) pm . The reaction of (NH4)(2)[IrCl6] with NH3 at 300 degrees C, however, gives the already known [Ir(NH3)(5)Cl]Cl-2 beside a small amount of [Ir(NH3)(4)C l-2]Cl-2. In pure form [Ir(NH3)(5)Cl]Cl-2 is obtained by ammonolysis of (NH 4)(2)[Ir(NH3)Cl-5] at 300 degrees C with NH3. [Ir(NH3)(4)Cl-2]Cl-2 crystall izes triclinic (P1, Z = 1, a = 660,2(3); b = 650,4(3); c = 711,1(2) pm; alp ha = 103,85(2)degrees, beta = 114,54(3)degrees, gamma = 112,75(2)degrees). The structure contains Cl- anions and [Ir(NH3)(4)Cl-2](2+) cations with a t rans position of the Cl atoms. Upon reaction of [Ir(NH3)(5)Cl]Cl-2 with Cl- 2 one ammine ligand is eliminated yielding [Ir(NH3)(4)Cl-2]Cl, which is tra nsformed to orthorhombic [Ir(NH3)(4)(OH2)Cl]Cl-2 (Pnma, Z = 4, a = 1335,1(3 ); b = 1047,9(2); c = 673,4(2) pm) by crystallization from water. In the oc tahedral complex [Ir(NH3)(4)(OH2)Cl](2+) the four ammine ligands have an eq uatorial position, whereas the Cl atom and the aqua ligand are arranged axi al. Oxidation of (NH4)(2)[Ir(NH3)Cl-5] with Cl-2 at 330 degrees C affords t he tetragonal Ir-IV complex (NH4)[Ir(NH3)Cl-5] (P4nc, Z = 2, a = 702.68(5); c = 912.89(9)pm). Its structure was determined using the powder diagram. O xidation of (NH4)(2)[Ir(NH3)Cl-5] with Br-2 in water, on the ether hand, gi ves (NH4)(2)[IrBr6] crystallizing in the K-2[PtCl6] type. Oxidation of (PPh 4)(2)[Ir(NH3)Cl-5] with PhI(OAc)(2) in CH2Cl2 affords the Ir-V amido comple x (PPh4)[Ir(NH2)Cl-5].