Metalloligands: Rhodium(III) Cyclometallated Compounds Containing Multitopological Binucleating Ligands

The reaction of [Rh(2-phenylpyridine)(2)Cl](2) with secondary dithiooxamides H(2)R(2)C(2)N(2)S(2) (R = isoamyl, isopropyl, {S}-phenylethyl, meso-phenylethyl) affords the contact ion pair [Rh(2-phenylpyridine)(2)(H(2)R(2)C(2)N(2)S(2) kappa-S,S- Rh)](+)Cl(-), which can be transformed into the neutral complexes [Rh(2-phenylpyridine)(2)(HR(2)C(2)N(2)S(2) kappa-S,S-Rh)]. The HCl exchange between the ion pairs and the corresponding neutral complexes has been studied by means of dynamic NMR spectroscopy techniques, and a mechanism for this exchange has been proposed. [Rh(2-phenylpyridine)(2){H(isoamyl)(2)C(2)N(2)S(2) kappa-S,S-Rh}] reacts with chlorido-bridged dimers [ML(n)Cl](2) {ML(n) = Pd(eta(3)-allyl), Rh(cyclooctadiene), (n-propyl)(3)PClPd} and provides the heterobimetallic complexes [Rh(2-phenylpyridine)(2)-{mu-(isoamyl)(2)C(2)N(2)S(2)}ML(n)]. Heterobimetallic complexes having the same formula and the same structure are obtained by reaction of [ML(n){H(isoamyl)(2)C(2)N(2)S(2) kappa-S,S-M}] species [ML(n) = Rh(1,5-cyclooctadiene), Pd(eta(3)-allyl), PdCl(tri-n-propylphosphane), PtCl(diphenyl-2-pyridylphosphane)] with [Rh(2-phenylpyridine)(2)Cl](2). The connectivity of the binucleating ligand diisoamyldithiooxamidate within the bimetallic complexes has been assessed. The linkage isomer obtained is [Rh(2-phenylpyridine)(2){mu-(isoamyl)(2)C(2)N(2)S(2)}ML(n)] (kappa-N,N-Rh(III), kappa-S,S-M). ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)