Synthesis and structural characterization of new rhodium formato complexes containing [Rh2]4+ and [Rh4]6+ cores

Binuclear Rh(II) complexes [Rh2(μ-OOCH)4(DMF)2] (1) and Na[Rh2(μ-OOCH)4(OOCH) (H2O)]·H2O (2), and the mixed-valence Rh(I)Rh(II) polynuclear rhodium complexes: [Rh4(μ-OOCH)4(bpy)4][PF6]2 (3), {[Rh2(μ-OOCH)2(bpy)2][PF6]·7H2O}n (4), and {[Rh2(μ-OOCH)2 (phen)2][PF6]·4H2O}n, (5), have been synthesized and characterized with spectroscopic methods. Structures of complexes 1, 2 and the tetranuclear compound 3 have been determined using X-ray crystallography. Compound 1 consists of well- separated molecular units, complex 2 has two-dimensional structure with binuclear [Rh2(μ-OOCH)4] units connected by Na+ ions with highly distorted octahedral coordination, and compound 3 [Rh4(μ-OOCH)4(bpy)4][PF6]2 is a linear tetranuclear cluster with two binuclear units [Rh2(μ-OOCH)2(bpy)2]+ connected by unbridged RhRh bond.