Synthesis, Characterization and Crystal Structures of New Ruthenium Carbonyl Clusters Derived from (9-Anthracenyl)diphenylphosphine

Thermal reaction of [Ru2(CO)6(μ-PFu2)(μ-η1,η2-Fu)] (Fu=2-furyl) with (9-anthracenyl)diphenylphosphine (AnPPh2) produces a novel diruthenium complex [Ru2(CO)5(μ-PFu2)(μ-η1,η1,η2-C14H8PPh2)] (1) in good yield whereas the corresponding reaction between [(μ-H)4Ru4(CO)12] and AnPPh2 gives [HRu(CO)3(PPh2C14H8)][(μ-H)4Ru4(CO)11(AnPPh2)] (2). Both compounds 1 and 2 were fully characterized by spectroscopic methods and their X-ray crystal structures were determined. For 1, initial coordination of the PPh2 functionality at the Ru atom is accompanied by cyclometalation of the anthracenyl ring to form a Ru–C σ bond together with concomitant formation of a π bond to the adjacent Ru center and loss of the furyl ligand. The formation of 2 involves the cleavage of two Ru–Ru bonds, and the making of a Ru–P bond, followed by orthometalation of the anthracenyl ring. The optical absorption and emission spectra of 1 were recorded and the results were correlated to the DFT calculations.