Synthesis and Structural Characterization of a Series of One-Dimensional Heteronuclear Dirhodium-Silver Coordination Polymers

Herein, we describe the preparation of heteronuclear dirhodium-silver complexes by reaction between molecular Rh(II)-Rh(II) compounds [Rh-2(-O2CR)(4)L-2] (R = Me, Ph (1), CH2OEt (2); L = solvent molecules) with paddlewheel structure and PPh4[Ag(CN)(2)]. One-dimensional coordination polymers of (PPh4)(n)[Rh-2(-O2CR)(4)Ag(CN)(2)](n) (R = Me (3), Ph (4), CH2OEt (5)) formula have been obtained by replacement of the two labile molecules in the axial positions of the paddlewheel structures by a [Ag(CN)(2)](-) bridging unit. The crystal structures of 3-5 display a similar arrangement, having anionic chains with a wavy structure and bulky (PPh4)(+) cations placed between the chains. The presence of the (PPh4)(+) cations hinders the existence of intermolecular Ag-Ag interactions although several C-H interactions have been observed. A similar reaction between [Rh-2(-O2CCMe3)(4)(HO2CCMe3)(2)] and PPh4[Ag(CN)(2)] led to the molecular compound (PPh4)(2){Rh-2(-O2CCMe3)(4)[Ag(CN)(2)](2)} (6) by replacement of the axial HO2CCMe3 ligands by two [Ag(CN)(2)](-) units. The trimethylacetate ligand increases the solubility of the complex during the crystallization favouring the formation of discrete heteronuclear species.