Reactivity of binuclear heterobridged iridium complexes with SnCl2

Abstract

The complex [Ir₂(µ-pz)(µ-SBu^t)(CO)₂{P(OMe)₃}₂]1(pz = pyrazolate) reacts with HgX₂(X = Cl or I)(1 : 2 molar ratio) to give the oxidation compounds [Ir₂(µ-pz)-(µ-SBu^t)X₂(CO)₂{P(OMe)₃}₂](X = Cl 2 or I 3). The addition of SnCl₂ to solutions of 2 or 3 leads to the trihalogenotin iridium complexes [Ir₂(µ-pz)(µ-SBu^t)(µ-SnCl₂X)₂(CO)₂{P(OMe)₃}₂](X = Cl 4 or I 5]. Treating 1 with SnCl₂ affords the adduct [Ir₂(µ-pz)(µ-SBu^t)(µ-SnCl₂)(CO)₂{P(OMe)₃}₂]6. The formulation of the compounds has been deduced by elemental analysis, IR, ³¹P and ¹¹⁹Sn NMR spectroscopy. The structure of one isomer of 4(4a) has been determined by X-ray diffraction methods: triclinic, space group P, with a= 11.896(2), b= 12.863(2), c= 13.943(3)Å, α= 69.27(1), β= 68.21(1), γ= 66.47(1)°, and Z= 2. The complex is binuclear with the metal atoms bridged by a pyrazolate and a SBu^t ligand. The Ir–Ir distance, 2.7221(6)Å, indicates the presence of a metal–metal bond.