221448-75-5Relevant academic research and scientific papers
Cationic 16-electron half-sandwich ruthenium complexes containing asymmetric diamines: Understanding the stability and reactivity of coordinatively unsaturated two-legged piano stool complexes
Gemel, Christian,Sapunov, Valentin N.,Mereiter, Kurt,Ferencic, Mathias,Schmid, Roland,Kirchner, Karl
, p. 114 - 120 (1999)
The cationic 16e complexes [RuCp*(η2(N,N)-Me2NCH2CH 2N(CH2CHMe2)2)]+ (1) and [RuCp*(η2(N,N)-Me2NCH2CH 2NCH2CH2OCH2CH2] + (2) as well as the 18e complex [RuCp*(η6-C6H5-N(Me)NCH 2CH2NMe2)]+ (3) have been synthesized as the BAr′4 (Ar′=3,5-C6H3(CF3)2) salts in one-pot reactions starting from [RuCp*(Cl)]4. For 1, the X-ray crystal structure has also been determined showing the absence of any agostic interactions between ruthenium and the C-H bonds of the diamine ligand, and only minor deviations from the planar geometry despite the bulky diamine ligand. Based on EH model calculations, the extraordinary kinetic inertness of the planar 16e [Cp*Ru(NN)]+ structure is traced to a high HOMO-LUMO gap deriving from through-bond coupling through the intervening σ skeleton of the chelating diamine (NN) ligand (in contrast to the P analogs) and further to the high π donor strength of Cp* (relative to parent Cp). Possible ligand rearrangements to increase the chemical reactivity are analyzed.
