Coordination Chemistry of 2,5,8-Trithia[9],(2,9)-1,10-phenanthrolinophane (L) toward Rhodium(III) at the Polarised Water/1,2-Dichloroethane Interface - A Possible New Approach to the Problem of Separating Rh~(III) from Chloride Media

摘要

The coordination chemistry involved in the assisted transfer of Rh~(III) by interfacial coordination with 2,5,8-trithia[9],(2,9)-1,10-phenanthrolinophane (L) has been studied at the water/1,2-dichloroethane interface by cyclic voltammetry. The dependence of the half-wave transfer potential on the ligand and metal concentrations suggests the [Rh(L)Cl_2]~+ formulation for the complex cation involved in the assisted transfer. In contrast, from the reaction of L in refluxing MeCN/water solution the [Rh(L)Cl][BF_4]_2·2MeCN compound has been isolated and structurally characterised. In the [Rh(L)Cl]~(2+) complex cation L acts as an N_2S_3 donor encapsulating the metal centre within a cavity having a square-based pyramidal geometry. A chloride ligand completes the distorted octahedral coordination sphere around the Rh~(III) ion.