Synthesis, structural characterization, antimicrobial and cytotoxic effects of aziridine, 2-aminoethylaziridine and azirine complexes of copper(ii) and palladium(ii)

摘要

The synthesis, spectroscopic and X-ray structural characterization of copper(ii) and palladium(ii) complexes with aziridine ligands as 2-dimethylaziridine HNCH _2CMe _2 (a), the bidentate N-(2-aminoethyl)aziridines C _2H _4NC _2H _4NH _2 (b) or CH _2CMe _2NCH _2CMe _2NH _2 (c) as well as the unsaturated azirine NCH _2CPh (d) are reported. Cleavage of the cyclometallated Pd(ii) dimer [μ-Cl(C _6H _4CHMeNMe _2-C,N)Pd] _2 with ligand a yielded compound [Cl(NHCH _2CMe _2)(C _6H _4CHMe _2NMe _2-C,N)Pd] (1a). The reaction of the aziridine complex trans-[Cl _2Pd(HNC _2H _4) _2] with an excess of aziridine in the presence of AgOTf gave the ionic chelate complex trans-[(C _2H _4NC _2H _4NH _2-N,N′) _2Pd](OTf) _2 (2b) which contains the new ligand b formed by an unexpected insertion and ring opening reaction of two aziridines ("aziridine dimerization"). CuCl _2 reacted in pure HNC _2H _4 or HNCH _2CMe _2 (b) again by "dimerization" to give the tris-chelated ionic complex [Cu(C _2H _4NC _2H _4NH _2-N,N′) _3]Cl _2 (3b) or the bis-chelated complex [CuCl(C _2H _2Me _2NC _2H _2Me _2NH _2-N,N′) _2]Cl (4c). By addition of 2H-3-phenylazirine (d) to PdCl _2, trans-[Cl _2Pd(NCH _2CPh) _2] (5d) was formed. All new compounds were characterized by NMR, IR and mass spectra and also by X-ray structure analyses (except 3b). Additionally the cytotoxic effects of these complexes were examined on HL-60 and NALM-6 human leukemia cells and melanoma WM-115 cells. The antimicrobial activity was also determined. The growth of Gram-positive bacterial strains (S. aureus, S. epidermidis, E. faecalis) was inhibited by almost all tested complexes at the concentrations of 37.5-300.0 μg mL ~(-1). However, MIC values of complexes obtained for Gram-negative E. coli and P. aeruginosa, as well as for C. albicans yeast, mostly exceeded 300 μg mL ~(-1). The highest antibacterial activity was achieved by complexes 1a and 2b. Complex 2b also inhibited the growth of Gram-negative bacteria.