Synthesis, characterization and crystal structures of some half-sandwich ruthenium(II) complexes of 1,4,7-trimethyl-1,4,7-triazacyclononane containing π-acidic ancillary ligands

Abstract

The synthesis of a series of ruthenium(II) complexes of 1,4,7-trimethyl-1,4,7-triazacyclononane L of type [RuL(X)Y(Z)]⁺ containing H, O₂CCF₃, CO, PPh₃, dppe [1,2-bis(diphenylphosphino)ethane] or 2,6-Me₂C₆H₃NC as auxiliary ligands are described where X = Y = CO, Z = Cl 1; X, Y = dppe, Z = Cl 2; X, Y = dppe, Z = H 3; X = CO, Y = PPh₃, Z = H 4; X = Y = 2,6-Me₂C₆H₃NC, Z = O₂CCF₃5. All complexes were characterized by spectroscopic methods. The crystal structures of 1 and 4 as PF₆^– salts have been determined. The two CO groups in complex 1 are in cis-fashion with a OC–Ru–CO angle of 90.1(3)° and the Ru–C distances are 1.850(6) and 1.893(6)Å. Complex 4 features one of the few ruthenium complexes containing three different piano-stool ligands, namely, CO, PPh₃ and H. The measured Ru–CO and Ru–H distances in 4 are 1.785(9) and 1.54(9)Å respectively.