η 3-Allyl rhodium complexes with azolate ligands. Crystal structures of the trinuclear 1,2,4-triazolate (tz) complexes [rh 3(μ-tz) 3(η 3-C 3H 5) 6] and...

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full title:η3-Allyl rhodium complexes with azolate ligands. Crystal structures of the trinuclear 1,2,4-triazolate (tz) complexes [rh3(μ-tz)3(η3-C3H 5)6] and [rh3(μ3-tz)(μ-Cl)Cl(η3-C 3H5)2(CO)4]·0.5C 2H4Cl2 The η3-allyl rhodium compound [Rh(acac)(η3-C3H5)2] (acac = acetylacetonate) reacts with azole ligands to give the new azolate complexes [Rh3(μ-az)3(η3-C3H 5)6] [az = tetrazolate (ttz) (1), 1,2,4-triazolate (tz) (2), benzotriazolate (btz) (3), or imidazolate (im) (4)]. A single-crystal X-ray diffraction study on complex (2) has established that its structure consists of discrete trinuclear complexes in which each rhodium atom is bridged by the 1,2,4-triazolate ligands through the non-adjacent nitrogen atoms to form a multiatomic ring. Complexes (2) and (1) react with [Rh2(μ-Cl)2(CO)4] to give the mixed-valence trinuclear complexes [Rh3(μ3-az)(μ-Cl)Cl(η3-C 3H5)2(CO)4] [az = tz (10) or ttz (11)]. The crystal structure of complex (10) has confirmed the existence of trinuclear molecules in which a chlorine atom and a triazolate bridge Rh(CO)2 and Rh(η3-C3H5)2 moieties; in addition the remaining nitrogen atom of the triazolate ligand completes the square-planar co-ordination of a RhCl(CO)2 unit. In the crystal, there is an intermolecular Rh-Rh distance of 3.393(1) Å. Complex (2) reacts with [Rh2(μ-Cl)2(η3-C3H 5)4] to give the trinuclear complex [Rh3(μ3-tz)(μ-Cl)Cl(η3-C 3H5)6]. Heterobridged binuclear pyrazolate (pz) complexes of formula [Rh2(μ-pz)(μ-X)(η3-C3H 5)4] (X = Cl, OH, or N3) have also been prepared.