Synthesis of <i>trans-</i>heteroleptic carboxylate-bridged paddlewheel-type diruthenium(II,II) complexes with poly aromatic hydrocarbon carboxylate

Abstract Four trans-heteroleptic paddlewheel-type diruthenium(II,II) compounds [Ru2(RCO2)2(2,6-(CF3)2ArCO2)2(THF)2] were synthesized using 4 types of polycyclic aromatic hydrocarbon (PAH) carboxylate RCO2− together with 2,6-bis(trifluoromethyl)benzoate (2,6-(CF3)2ArCO2−) and tetrahydrofuran (THF) as axial capping ligands. The redox potential (E1/2) for [Ru2II,II]/[Ru2II,III]+ was observed in the range of 48 to 116 mV, and the HOMO energy level calculated based on the atomic coordinates of the solid-state structure was found in the narrow range of −4.31 to −4.42 eV, which was hardly affected by the PAHs introduced.