491832-68-9Relevant academic research and scientific papers
Simultaneous cation/anion coordination by bifunctional 1,2-diimine/1,2-diamine type ligands: Synthesis, structures, and properties of tight ion pair complexes of ruthenium and iron
Rau, Sven,Boettcher, Lars,Schebesta, Sebastian,Stollenz, Michael,Goerls, Helmar,Walther, Dirk
, p. 2800 - 2809 (2007/10/03)
The reaction between [η6-p-cymene)RuCl2]2 and tetra-p-tolyloxalic amidine (oxam1) results in a coupled cation/anion coordination forming the ion-paired complex [(η6-p-cymene)RuCl(oxam1)Cl] (1a). According to an X-ray single crystal diffraction analysis the Ru moiety is coordinated at the 1,2-diimine part yielding a five-membered chelate ring. Furthermore, the 1,2-diamine group on the opposite side binds to a chloride anion via two N-H groups. Exchange of the chloride anion by trifluoractetate yields [(η6-p-cymene)RuCl(oxam1)CF3CO2] (1c) in which the C=O group is bonded to the diamine part. Similarly, bis(mesityl)bis(pyridylmethyl)oxalic amidine (oxam2) reacts with FeX2 to yield the ion-paired complexes 3a (X: Cl), and 3b (X: Br). X-ray diffraction studies of both compounds reveal that the oxalic amidine ligand acts as a four-dentate chelating ligand. One halide is fixed in the same way as in 1a. The complex 1a reacts with Pd(acac)2 (acac: acetylacetonate) to give the tetranuclear heterobimetallic complex [(η6-p-cymene)RuCl-(oxam1)PdCl]2 (2). The related complexes [(tbbpy)2Ru-(bbimH2)(OOC-CF3)] (PF6) (4), [(tbbpy)2Ru(bbimH2){OOC- (CF2)7CF3})][OOC(CF2) TCF3] (5), [{(tbbpy)2Ru(bbimH2)}2- (OOC-C6F4-COO)](PF6)2 (6), and [{(tbbpy)2Ru-(bbimH2)}2 (OOC-C6F4-COO)] (7), (bbimH2: bibenzimidazole; tbbpy: 4,4′-di-tert-butyl-2,2′-bipyridine) also form ion-paired compounds. According to the X-ray diffraction analyses of 4-6 both oxygen atoms of the carboxylate ions are coordinated to the two N-H functions via strong N-H...O bonds. Although 5 contains a dication, the compound is soluble in solvents of low polarity, even in supercritical carbon dioxide. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
