Combining two coordinatively unsaturated diruthenium cores by the tetradentate ligand (Ph2P)2NCH2C6H4CH2N(PPh2)2

The tetradentate N,N-bis(diphenylphosphanyl)amine ligand (Ph2P)2NCH2C6H4CH2N(PPh2)2 (1, xdppa) reacted with in situ prepared [Ru2(μ-H)(μ-PBut2)(PBut2H)2(CO)4] (2) in a molar ratio of 1:2 affording the novel twofold coordinatively unsaturated tetranuclear metal complex [Ru2(μ-H)(μ-PBut2)(CO)4(μ-xdppa)Ru2(μ-H)(μ-PBut2)(CO)4] (3). Compound 3 was protonated by tetrafluoroboric acid at each side of the unsaturated diruthenium frameworks affording the oxidative addition product [Ru2(μ-H)2(μ-PBut2)(CO)4(μ-xdppa)Ru2(μ-H)2(μ-PBut2)(CO)4](BF4)2 (4). All new compounds were characterized by spectroscopic means and the molecular structures of compounds 1 and 4 were determined by X-ray diffraction.

Graphical abstractThe synthesis of the tetradentate N,N-bis(diphenylphosphanyl)amine ligand (Ph2P)2NCH2C6H4CH2N(PPh2)2 (1, xdppa) as well as the related twofold coordinatively unsaturated complex [Ru2(μ-H)(μ-PBut2)(CO)4(μ-xdppa)Ru2(μ-H)(μ-PBut2)(CO)4] (3) is reported. The molecular structure of 3 was confirmed indirectly by derivatization with HBF4 to the corresponding oxidative addition product [Ru2(μ-H)2(μ-PBut2)(CO)4(μ-xdppa)Ru2(μ-H)2(μ-PBut2)(CO)4](BF4)2 (4) established by crystal structure analysis.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The synthesis of a twofold coordinatively unsaturated tetraruthenium complex is reported. ► The tetraruthenium complex reacted with tetrafluoroboric acid by oxidative addition. ► The molecular structure of the addition product was determined by X-ray crystallography.