η5-Pentamethylcyclopentadienylruthenium(II) complexes containing η6-coordinated α-amino acids

Article abstract of DOI:10.1016/0022-328X(94)80165-7

Reaction of *RuCl2>2 with L-alanine (L-alaH) in methanol at room temperature in the presence of NaOMe yields the complex Na*RuCl(L-ala(> (1), which contains a five-membered N,O-coordinated chelate ring.The analogous complex Na*RuCl(L-phe)> (2) is obtained under similar conditions but at 0 deg C in 90percent yield.At temperatures above 20 deg C both 2 and the η⁶-coordinated complex *Ru(L-pheH)>Cl (4) are obtained, with the proportion of the latter increasing with temperature.Compound 4 is obtained in 88percent yield by refluxing *RuCl2>2 and L-phenylalanine (L-pheH) in CH3OH/CH3ONa followed by separation from 2.The analogous ruthenium(II) sandwich complexes 5-10 were obtained from L-tyrosine and L-tryptophane and various derivatives. *Ru(L-met)> (3), prepared by the reaction of *RuCl2>2 with L-methionine (L-metH) in CH3OH/CH3ONa, displays N,O,S-coordination. Key words: Ruthenium; Cyclopentadienyl; Amino acid; ?-Bonding