Heterotrinuclear angular aggregates of rhodium, iridium, palladium and Group 11 metals. X-Ray structure of the complex [(cod)2Rh2(µ3-C7H4NS2)2Ag(O2ClO2)](cod = cycloocta-1,5-diene)

Abstract

The binuclear complexes [{Ir(µ-C₇H₄NS₂)(cod)}₂]1(cod = cycloocta-1,5-diene) and [{Pd(µ-C₇H₄NS₂)(η³-C₃H₅)}₂]2 are isolated from the reaction of the chloro-bridged compounds [{M(µ-Cl)L₂}₂](M = Ir, L₂= cod; M = Pd, L₂= allyl) and lithium benzothiazole-2-thiolate. Reactions of 1 and 2 with the appropriate species [ML₂(Me₂CO)₂]⁺ afford the homotrinuclear angular aggregates [M₃(µ₃-C₇H₄NS₂)₂(L₂)₃]⁺. Starting from [{Rh(µ-C₇H₄NS₂)(CO)(PPh₃)}₂] and [{M′(µ-C₇H₄NS₂)(cod)}₂](M′= Rh or Ir), this method is highly useful to prepare the heterotrinuclear aggregates [(Ph₃P)₂(OC)₂Rh₂(µ₃-C₇H₄NS₂)₂ML₂]⁺[ML₂= Ir(cod) or Pd(allyl)], [(cod)₂M′₂(µ₃-C₇H₄NS₂)₂AgX]ⁿ⁺(n= 0, X = ClO₄, Cl, NO₃ or BF₄; n= 1, X = PPh₃ or pyridine) and [(cod)₂M′₂(µ₃-C₇H₄NS₂)₂M″Cl](M″= Cu or Au). They have been characterized by ¹H, ³¹P NMR and IR spectroscopy and [(cod)₂Rh₂(µ₃-C₇H₄NS₂)₂Ag(O₂ClO₂)]8 by X-ray diffraction methods. Crystals of 8 are orthorhombic, space group Pbcn, with a= 7.635(5), b= 27.564(11), c= 15.564(8)Å, Z= 4. The structure has been solved from diffractometer data by direct and Fourier methods and refined by full-matrix least squares to R= 0.062 for 1863 observed reflections. The complex, having an imposed C₂ symmetry, shows two Rh and one Ag atoms in a bent arrangement with two molecules of benzothiazole-2-thiolate interacting with all three metals. Each ligand is bonded to one Rh atom through the nitrogen and asymmetrically bridges one Rh and one Ag atom through the sulphur. The Rh atoms complete their co-ordination with a cod ligand interacting through the two olefinic bonds, while the Ag atom completes the co-ordination with two oxygen atoms from a perchlorate anion, which has been found disordered and distributed in two positions of equal occupancy factor with three oxygen atoms in common.