3-Methylindole-Based Tripodal Tetraphosphine Ruthenium Complexes in N₂ Coordination and Reduction and Formic Acid Dehydrogenation

The ruthenium(II) complexes RuCl₂L1^H, RuCl₂L1^CF3, RuCl₂L1^OMe and RuCl₂L2^H were synthesized from [Ru(η⁶-benzene)Cl(μ-Cl)]₂ and the corresponding tripodal tris-3-methylindolephosphine-based ligands L1^H, L1^CF3, L1^OMe, and L2^H. Stoichiometric reduction of these complexes with KC₈ yielded the corresponding ruthenium(0) dinitrogen complexes. The latter complexes were studied in the N₂ reduction with chlorosilanes and KC₈, yielding stoichiometric amounts of the silylamines. The synthesized ruthenium(II) complexes are also active catalysts for the formic acid dehydrogenation reaction.