REACTION OF [RUCL2(PPH3)3] WITH ALPHA-AMINO-ACIDS - SYNTHESIS AND X-RAY STRUCTURAL CHARACTERIZATION OF THE SCHIFF-BASE COMPLEXES (RU[(CH3)2C-NCH(H)COO]2(PPH3)2), RU[CH3)2C-NCH(CH3)COO]2(PPH3)2)

Complexes of the type [Ru(aa)2(PPh3)2], (aaHgly (1), L-ala (2), L-val (3)) may be prepared by the reaction of [RuCl2(PPh3)3] with aaH in methanol at reflux. 2 crystallizes as the Δ diastereomer. A crystal structure analysis established that a carboxyl oxygen of the first and an ammine nitrogen of the second L-alaninate ligand are sited trans to cis-positioned triphenylphosphine ligands. Whereas the 31p1H NMR spectrum of 3 indicated a similar ligand arrangement for this complex, magnetic equivalence of the phosphorus atoms was established for 1. The presence of two AB quartets in the 31P1H NMR spectra of 2 and 3 suggests that both the Λ and Δ diastereomers are present in methanol solution. Reaction of [RuCl2(PPh3)3] with glycine or L-alanine in acetone leads to the formation of the Schiff base complexes {Ru[(CH3)2C:NCH(R)COO]2(PPh3)2}, (R H(4), R CH3(5)). In contrast, 3 is obtained once again with L-valine. Crystal structures were performed for 4 and 5. The PPh3 ligands are sited trans to one another in 4 and to ammine nitrogens in 5, which crystallizes as the Λ diastereomer. © 1990.