Trindane-ruthenium sandwich complexes: An NMR and X-ray crystallographic study of [(trindane)RuCl2]2, (trindane)RuCl2[P(OMe)3], and [(trindane)2Ru][BF4]2

Trindane and [(p-cymene)RuCl2]2 react in the melt to yield [(trindane)RuCl2]2 (4), the NMR spectra of which reveal the presence of [{(trindane)Ru}2(μ-Cl)3]Cl (6) in solution. The X-ray crystal structure of 4 reveals that two of the cyclopentene rings adopt endo envelope conformations, while the third five-membered ring is folded in an exo fashion to avoid a terminal chlorine in the other half of the dimer. Bridge cleavage with trimethyl phosphite gives (trindane)RuCl2[P(OMe)3] (8), and the X-ray crystal structure shows that all three peripheral rings are folded such that the wingtip methylene groups are oriented toward the metal. Finally, treatment of 4 with excess trindane in the presence of AgBF4 yields the dicationic sandwich compound [(trindane)2Ru]²⁺ 2BF4^- (3).