Half-sandwich type rhodium(III)-aminohydroxamate complexes: the role of the position of the amino group in metal ion binding

0502720 - BFÚ 2019 RIV GB eng J - Článek v odborném periodiku
Parajdi-Losonczi, P.L. - Buglyo, P. - Skakalova, H. - Kašpárková, Jana - Lihi, N. - Farkas, E.
Half-sandwich type rhodium(III)-aminohydroxamate complexes: the role of the position of the amino group in metal ion binding.
New Journal of Chemistry. Roč. 42, č. 10 (2018), s. 7659-7670. ISSN 1144-0546. E-ISSN 1369-9261
Institucionální podpora: RVO:68081707
Klíčová slova: pentamethylcyclopentadienyl rhodium complexes * comparative solution equilibrium * x-ray * organometallic complexes
Obor OECD: Inorganic and nuclear chemistry
Impakt faktor: 3.069, rok: 2018

Complex formation equilibria between [(eta(5)-Cp*) Rh-III(H2O)(3)](2+) and aminohydroxamic acids (L-2-aminoN-hydroxyacetamide (alpha-alahaH), 3-amino-N-hydroxypropanamide (beta-alahaH) and 4-amino-N-hydroxybutanamide (GABAha, gamma-abhaH)) having the primary amino group in different chelatable positions relative to the hydroxamic function were studied using pH-potentiometric, H-1 NMR and ESI-MS methods and the formation constants of the complexes present in aqueous solution are reported. The relative order of the pH-dependent conditional stability of the hydroxamate type (O,O) and (N-amino, N-hydroxamato) chelates was found to determine to a great extent the coordination modes both in the mono-and various dinuclear species formed. While with alpha-alaha(-), a 5-membered (N,N) chelated mononuclear complex predominates, with beta-alaha-in a wide pH-range, very stable dinuclear cluster ions exist. With gamma-abha(-), in the most stable complexes, two ligands (in reverse variation) link two half-sandwich cations, coordinating each ligand via the hydroxamate chelate to one metal centre, while via the amino-N to the other one. This arrangement seems to be further stabilized by a hydrogen bond as DFT calculations support the extra stabilization effect of internal H-bonding in [{(eta(5)-Cp*) Rh-III}(2)H1(gamma-abha)(2)](+). The synthesis, spectral (NMR and IR) and MS characterization of a novel complex with an iridium analogue, [(eta(5)-Cp*) Ir-III(alpha-alaha) Br] (1) is also described. This complex was tested for its in vitro cytotoxicity using human-derived cancer cell lines (A2780, HeLa, DU-145, A549, and MCF-7) and showed insignificant anti-proliferative activity in the micromolar concentration range.
Trvalý link: http://hdl.handle.net/11104/0294619