New binuclear complexes of formula [M2(μ-tz)2(L2)2] [tz = triazolate; M = Rh or Ir, L2 = diolefin, (CO)2, or (CO)(PPh3); M = Pd, L2 = η3-C3H5 or η3-C4H7] have been prepared. These binuclear complexes, having unco-ordinated N atoms from the triazolate ligands, react with [M2(μ-Cl)2(L2)2] (M = Rh, Ir, or Pd) to give tetranuclear compounds of formula [Rh2M2(μ3-tz)2Cl 2(L2)4]. The latter complexes can also be prepared by reacting triazole and [Rh(acac)(CO)2] with [M2(μ-Cl)2(L2)2]. The heteronuclear rhodium-gold complex [Rh2Au2(μ3-tz)2Cl 2(cod)2] (cod = cyclo-octa- 1,5-diene) has been synthesized. Trinuclear complexes of formula [Rh2M(μ3-tz)(μ-X)ClL2(CO)4] (X = Cl or OH) have been isolated by several routes starting from the above mentioned tetra-, bi-, or mononuclear complexes. In general, these trinuclear complexes show metallic lustre and marked dichroism, suggesting metal-metal interactions which were confirmed by the X-ray determination of [Rh3(μ3-tz)(μ-Cl)Cl(tfbb)(CO)4] (tfbb = tetrafluorobenzobarrelene). This complex shows a stacking arrangement of centred rhodium units with an intermetallic separation of 3.425(4) Å.

We thank the We thank the Comision Asesora de Investigacion Cientifica y Tecnica (Spain) for financial support and Professor S. GarciaBlanco for facilities

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