Mononuclear complexes of copper(I), palladium(II), and ruthenium(II) with oxalic amidine-type ligands by coupled cation-/anion coordination

Oxalamidines (RN)-N-1=C(NHR2)-C(=NHR2) =NR1 (H(2)A: R-1 = R-2 = p-tolyl; H2B: R-1 = R-2 = mesityl) react with [Cu(CH3CN)(4)(BF4)/PPh3 to form the mononuclear complexes {[(Ph3P)(2)Cu]AH(2)(F4B)} (1) and {[(Ph3P)Cu]BH2(F4B)} (2). X-ray diffraction measurements of single crystals show that Cu-I is coordinated at the 1,4-diazadiene unit. Tetrafluoroborat is bonded at the 1,2-diamine unit via hydrogen bonds ("coupled cation-/anion coordination"). [(allyl)PdCl](2) reacts with H(2)A to form the allyl complex [(allyl)PdAH(2)...Cl-2(allyl)Pd] (3). With H2B the analogous compound 4 is formed. In these complexes the (allyl)Pd+-fragment is coordinated at the 1,4-diazadiene part of the neutral oxalic amidine ligand. In addition, [allylPdCl(2)](-) coordinates at the 1,2-diamine site. By analogous coupled cation-/anion coordination some Run complexes, e. g. [(p-cymolRu(Cl)CH2...Cl] (6), and [(4,4',4"-tri-t-butyl-terpyridin)(Cl)RuAH(2)...Cl] (9) can be prepared.