Metal complexes of biologically important ligands, LXXVIII. Synthesis of palladium complexes of ferrocenyl-substituted amino acid derivatives

Abstract

Schiff bases from ferrocene aldehyde and α-amino acidates react with PdCl2 or Na2PdCl4 to give N,O-chelate complexes (2a–e, 3). The related N-ferrocenylmethylen-α-amino acid esters give, with Pd(OAc)2, cyclopalladated acetate-bridged complexes (4a,b). N,O-chelate complexes (5–7) are obtained from Na2PdCl4 with N-ferrocenylmethyl prolinate and-alaninate as well as with N,N-dibenzyl glycinate. The ethyl ester of N,N-dibenzylglycine and Pd(OAc)2 form the cyclopalladated acetate-bridged complex 8, while the ester of N-monobenzylglycine and Na2PdCl4 affords trans-PdCl2(L)2 with a monodentate N-coordinated ligand. The structures of 2a, 4a, 5, 7, and 9 were determined by X-ray diffraction. Keywords: ferrocene, amino acids, palladium(II) complexes, crystal structures.

Preparation, Reactivity and Peptide Labelling Properties of (η6‐Arene)ruthenium(II) Complexes with Pendant Carboxylate Groups

“…A range of sandwich complexes have been prepared for this purpose in recent years including the ferrocenylmethyl [30,31] and [(η 5 -Cp*)M{η 6 - nϩ (R ϭ N-succinimide; M ϭ Ir, n ϭ 2; M ϭ Ru, n ϭ 1) fragments. [32,33] We, therefore, prepared both [(η 6 -C 6 Me 6 )Ru(η 6 -ppa)](OTf) 2 and [(η 6 -C 6 Me 6 )Ru(η 6 -pba)](OTf) 2 (10) as potential N-terminal labels for peptides.…”

Ferrocenoyl-amino acids: redox response towards di- and trivalent metal ions

“…Some metal complexes of Fc amino acid conjugates have been reported in the literature over the years. Ferrocenylimines of the amino acids Gly, Ala, Leu and Val and ferrocenylmethyl amino acid conjugates of Ala and Pro were exploited by Beck and coworkers as ligands for Pd(II) [17] giving a series of mononuclear or binuclear complexes in which N,O-chelation of the ligand was observed. Similarly, metal complexes of bisdimethyl ferrocenoyl derivatives of Gly, Ala, Phe and Tyr were used for their antibacterial properties [18].…”

Metal Complexes of Biologically Important Ligands, CLXXII [1]. Metal Ions and Metal Complexes as Protective Groups of Amino Acids and Peptides – Reactions at Coordinated Amino Acids

“…The Fem group can be easily introduced by reaction of cysteine with ferrocenyl methanol [253] in the presence of acid whereby the ferrocenylmethyl cation as active species [254] is added to the thiol group and can be selectively cleaved [251,252]. Fem amino acids have been used as ligands in Pd(II) complexes [247], and the anions of ferrocenylmethyl-S-cysteine and ferrocenylenbis(methyl-S-cysteine) (60) (Scheme 11) have been proven as multidendate ligands to yield coordination polymers [255].…”