Synthesis and structural characterization of Rh(III) complexes containing diamino ligands of types [D(C6H4NH2)2] and [D(C6H4CH2NHEt)2] (D = O, S) bearing different spacers.

The reaction of the diamino ligands of general formula {D(C6H4NH2)2} [D = O (L1); S (L2)] and {D(C6H4CH2NHEt)2} [D = O (L3); S (L4)] with RhCl33H2O yielded neutral coordination complexes [RhIII(Ln)Cl3] [n = 1 (1); n = 2 (2); n = 3 (4); n = 4 (5)]. Compound 1 in N,N-dimethylformamide solution promoted the formation of the neutral complex [RhIII(L1)(dmf)Cl3] (3). A zwitterionic complex [RhIII(HL4)Cl4] (6) was obtained from the reaction of L4 with RhCl33H2O as a minor compound. All complexes were characterized in solution by NMR and by vibrational spectroscopy in solid state. Crystal structures of the chlorohydrates [H2L3]Cl2H2O, [H2L4]Cl2, and the complexes 2?6 were identified by X-ray diffraction studies. Molecular structures of the complexes revealed different coordination patterns of the diamino ligands Ln as well as the formation of chelate rings of five-, six-, and eight members. The presence of N?H groups in the title compounds enhanced the formation of hydrogen bond networks that were analyzed on the basis of a graph set analysis approach, displaying rings at the first to third level.