Synthesis and Characterization of Mononuclear Indoline Complexes. Studies of σ and π Bonding Modes

The dication [(cymene)Ru(η 6 -1-Me-indoline)] 2+, 1a, has been synthesized either by the hydrogenation of [(cymene)Ru(1-Me-indole)] 2+ or by the reaction of [(cymene)Ru(OTf) 2 ] x with 1-Me-indoline and has been isolated as the triflate or tetraphenylborate salt. Other [(arene)Ru(indoline)] 2+ derivatives have also been prepared by similar methods. [ 1a ](BPh 4 ) 2 crystallized in the space group P 1̄ with a = 10.9308(3) Å, b = 14.1874(4) Å, c = 18.4139(5) Å, α = 81.800(1)°, β = 75.17°, γ = 89.50°, V = 2731.19(13) Å 3, and Z = 2. The sandwich structure is slightly bent with an angle between the ruthenium ion and the center of each η 6 -ligand of 174.3°. Complexes with η 1 -N-coordinated indoline ligands have also been characterized. The reaction of indoline with Pd(Cl) 2 (PPh 3 )(CH 3 CN) in refluxing dichloromethane resulted in the formation of (Cl) 2 (PPh 3 )Pd(η 1 -indoline), 2, which was isolated and characterized by spectroscopic methods. Complex 2 crystallized in the space group P 1̄ with a = 9.703(2) Å, b = 10.148(2) Å, c = 13.920(2) Å, α = 99.650(10)°, β = 99.230(10)°, γ = 94.560(10)°, V = 1325.8(3) Å 3, and Z = 2. The indoline ligand is tilted with respect to the metal−ligand plane, and the five-membered ring of the ligand assumes an envelope-type conformation.