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Pivarcsik T, Kiss MA, Rapuš U, Kljun J, Spengler G, Frank É, Turel I, Enyedy ÉA. Organometallic Ru(II), Rh(III) and Re(I) complexes of sterane-based bidentate ligands: synthesis, solution speciation, interaction with biomolecules and anticancer activity. Dalton Trans 2024; 53:4984-5000. [PMID: 38406993 DOI: 10.1039/d3dt04138g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
In this study, we present the synthesis, characterization and in vitro cytotoxicity of six organometallic [Ru(II)(η6-p-cymene)(N,N)Cl]Cl, [Rh(III)(η5-C5Me5)(N,N)Cl]Cl and [Re(I)(CO)3(N,N)Cl] complexes, in which the (N,N) ligands are sterane-based 2,2'-bipyridine derivatives (4-Me-bpy-St-OH, 4-Ph-bpy-St-OH). The solution chemical behavior of the ligands and the complexes was explored by UV-visible spectrophotometry and 1H NMR spectroscopy. The ligands and their Re(I) complexes are neutral at pH = 7.40; this contributes to their highly lipophilic character (log D7.40 > +3). The Ru(II) and Rh(III) half-sandwich complexes are much more hydrophilic, and this property is greatly affected by the actual chloride ion content of the medium. The half-sandwich Ru and Rh complexes are highly stable in 30% (v/v) DMSO/water (<5% dissociation at pH = 7.40); this is further increased in water. The Rh(III)(η5-C5Me5) complexes were characterized by higher water/chloride exchange and pKa constants compared to their Ru(II)(η6-p-cymene) counterparts. The Re(I)(CO)3 complexes are also stable in solution over a wide pH range (2-12) without the release of the bidentate ligand; only the chlorido co-ligand can be replaced with OH- at higher pH values. A comprehensive discussion of the binding affinity of the half-sandwich Ru(II) and Rh(III) complexes toward human serum albumin and calf-thymus DNA is also provided. The Ru(II)(η6-p-cymene) complexes interact with human serum albumin via intermolecular forces, while for the Rh(III)(η5-C5Me5) complexes the coordinative binding mode is suggested as well. They are also able to interact with calf-thymus DNA, most likely via the coordination of the guanine nitrogen. The Ru(II)(η6-p-cymene) complexes were found to be the most promising among the tested compounds as they exhibited moderate-to-strong cytotoxic activity (IC50 = 3-11 μM) in LNCaP as well as in PC3 prostate cells in an androgen receptor-independent manner. They were also significantly cytotoxic in breast and colon adenocarcinoma cancer cell lines and showed good selectivity for cancer cells.
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Affiliation(s)
- Tamás Pivarcsik
- MTA-SZTE Lendület Functional Metal Complexes Research Group, Department of Molecular and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7-8., H-6720 Szeged, Hungary.
- Department of Molecular and Analytical Chemistry, University of Szeged, Dóm tér 7-8., H-6720 Szeged, Hungary
| | - Márton A Kiss
- Department of Molecular and Analytical Chemistry, University of Szeged, Dóm tér 7-8., H-6720 Szeged, Hungary
| | - Uroš Rapuš
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Jakob Kljun
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Gabriella Spengler
- MTA-SZTE Lendület Functional Metal Complexes Research Group, Department of Molecular and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7-8., H-6720 Szeged, Hungary.
- Department of Medical Microbiology, Albert Szent-Györgyi Health Center and Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis u. 6, H-6725 Szeged, Hungary
| | - Éva Frank
- Department of Molecular and Analytical Chemistry, University of Szeged, Dóm tér 7-8., H-6720 Szeged, Hungary
| | - Iztok Turel
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Éva A Enyedy
- MTA-SZTE Lendület Functional Metal Complexes Research Group, Department of Molecular and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7-8., H-6720 Szeged, Hungary.
- Department of Molecular and Analytical Chemistry, University of Szeged, Dóm tér 7-8., H-6720 Szeged, Hungary
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Nagy S, Ozsváth A, Bényei AC, Farkas E, Buglyó P. Donor Atom Preference of Organoruthenium and Organorhodium Cations on the Interaction with Novel Ambidentate (N,N) and (O,O) Chelating Ligands in Aqueous Solution. Molecules 2021; 26:molecules26123586. [PMID: 34208223 PMCID: PMC8230953 DOI: 10.3390/molecules26123586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/04/2021] [Accepted: 06/04/2021] [Indexed: 11/16/2022] Open
Abstract
Two novel, pyridinone-based chelating ligands containing separated (O,O) and (Namino,Nhet) chelating sets (Namino = secondary amine; Nhet = pyrrole N for H(L3) (1-(3-(((1H-pyrrole-2-yl)methyl)-amino)propyl)-3-hydroxy-2-methylpyridin-4(1H)-one) or pyridine N for H(L5) (3-hydroxy-2-methyl-1-(3-((pyridin-2-ylmethyl)amino)propyl)pyridin-4(1H)-one)) were synthesized via reduction of the appropriate imines. Their proton dissociation processes were explored, and the molecular structures of two synthons were assessed by X-ray crystallography. These ambidentate chelating ligands are intended to develop Co(III)/PGM (PGM = platinum group metal) heterobimetallic multitargeted complexes with anticancer potential. To explore their metal ion binding ability, the interaction with Pd(II), [(η6-p-cym)Ru]2+ and [(η5-Cp*)Rh]2+ (p-cym = 1-methyl-4-isopropylbenzene, Cp* = pentamethyl-cyclopentadienyl anion) cations was studied in aqueous solution with the combined use of pH-potentiometry, NMR and HR ESI-MS. In general, organorhodium was found to form more labile complexes over ruthenium, while complexation of the (N,N) chelating set was slower than the processes of the pyridinone unit with (O,O) coordination. Formation of the organoruthenium complexes starts at lower pH (higher thermodynamic stabilities of the corresponding complexes) than for [(η5-Cp*)Rh]2+ but, due to the higher affinity of [η6-p-cym)Ru]2+ towards hydrolysis, the complexed ligands are capable of competing with hydroxide ion in a lesser extent than for the rhodium systems. As a result, under biologically relevant conditions, the rhodium binding effectivity of the ligands becomes comparable or even slightly higher than their effectivity towards ruthenium. Our results indicate that H(L3) is a less efficient (N,N) chelator for these metal ions than H(L5). Similarly, due to the relative effectivity of the (O,O) and (N,N) chelates at a 1:1 metal-ion-to-ligand ratio, H(L5) coordinates in a (N,N) manner to both cations in the whole pH range studied while, for H(L3), the complexation starts with (O,O) coordination. At a 2:1 metal-ion-to-ligand ratio, H(L3) cannot hinder the intensive hydrolysis of the second metal ion, although a small amount of 2:1 complex with [(η5-Cp*)Rh]2+ can also be detected.
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Affiliation(s)
- Sándor Nagy
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Hungary; (S.N.); (A.O.); (E.F.)
| | - András Ozsváth
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Hungary; (S.N.); (A.O.); (E.F.)
| | - Attila Cs. Bényei
- Department of Physical Chemistry, University of Debrecen, H-4032 Debrecen, Hungary;
| | - Etelka Farkas
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Hungary; (S.N.); (A.O.); (E.F.)
| | - Péter Buglyó
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Hungary; (S.N.); (A.O.); (E.F.)
- Correspondence:
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