Pyridyl-Substituted Indenyl Ruthenium Complexes: Synthesis, Structures, and Reactivities

Abstract

We have investigated the synthesis of a novel pyridyl-substituted indenyl trinuclear ruthenium complex, {μ2-η5:η1-(C5H4N)(C9H5)}Ru3(CO)9 (1), and its reactivities with pyridine derivatives, PPh3, and different types of alkenes. Complex 1 was synthesized in 89% yield from Ru3(CO)12 and 3-(2-pyridyl)indene (1:1 mol ratio) in refluxing heptane. The reaction of 1 with a 5-fold excess of 3-(2-pyridyl)indene gave two complexes, {η1-(C5H4N)(C9H6)}2Ru(CO)2 (2) and {η5-(C5H4N)(C9H6)}{η1-(C5H4N)(C9H6)}Ru2(CO)4 (3). Both were also converted back to 1 in the presence of an equimolar amount of Ru3(CO)12, although the yields were low. Reaction of 1 in refluxing toluene afforded an unexpected complex, {μ3-η6:η3:η1-(C5H4N)(C9H5)}Ru3(CO)7 (4), via the loss of two CO groups. Complex 4 represents a completely new type of coordination mode (μ3-η6:η3:η1) of indenyl ligands in transition metal complexes. The reactions of 1 with 2-(2-pyridyl)indene, 1,2,3,5-tetramethyl-4-(2-pyridyl)cyclopentadiene, 1,2-diphenyl-4-(2-pyridyl)cyc...