Structural and solution speciation studies on fac-tricarbonylrhenium(I) complexes of 2,2′-bipyridine analogues

Pivarcsik, Tamás (author), Kljun, Jakob (author), Clemente Rodriguez, Sergio (author), Cortés Alcaraz, David (author), Rapuš, Uroš (author), Nové, Márta (author), Várkonyi, Egon F. (author), Nyári, József (author), Bogdanov, Anita (author), Spengler, Gabriella (author), Turel, Iztok (author), Enyedy, Éva A. (author)

In this study, we report the synthesis and characterization of 12 novel rhenium(I) complexes with the general formula fac-[Re(CO)$_3$(NN)X]$^{n+}$ where (NN) is a 2,2′-bipyridine analogue ligand, X = Cl$^–$, Br$^–$, or H$_2$O, and n = 0 or 1, focusing on their speciation in an aqueous solution. The prepared organorhenium complexes are stable in a wide pH range in an aqueous solution, and no release of the bidentate ligands or the carbonyl ligands was observed. The stability of the complexes in various biologically relevant matrices (cell culture medium and real blood serum) was also demonstrated. However, the simultaneous substitution of the halido ligand by water and slow hydrolysis of the ester bonds in the ligands were observed, affecting both the solubility and the lipophilicity of the compounds. The aqua complexes became more lipophilic in the presence of chloride ions, while the hydrophilicity increased significantly with time due to the hydrolysis of the ester bonds, which probably contributed to their weak pharmacological activity. The results also showed kinetically hindered aqueous solvation of the halido complexes and low chloride ion affinity of the aqua complexes. The deprotonation of the coordinated aqua ligand in the complexes occurs in the pH = 7–10 range, leading to significant formation (18–30%) of hydroxido species at pH = 7.4. The halido complexes showed somewhat higher cytotoxicity (IC$_{50}$ = 60–99 μM) on human colon adenocarcinoma cancer cells (Colo205 and Colo320) than the corresponding aqua complexes (IC50 > 100 μM). In all cases, no antibacterial effect was observed (MIC > 100 μM), but some of the complexes showed moderate antiviral activity (IC$_{50}$ ∼ 50 μM) on Herpes simplex virus 2.

• Language: English
• Keywords: rhenium, organorhenium(I) carbonyl ligands, pyridine ligands
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2024
• Number of pages: Str. 44601-44615
• Numbering: Vol. 9, iss. 44
• PID: 20.500.12556/RUL-165001
• UDC: 546.719:547.82
• ISSN on article: 2470-1343
• DOI: 10.1021/acsomega.4c07117
• COBISS.SI-ID: 215709955
• Publication date in RUL: 20.11.2024

Record is a part of a journal

• Title: ACS omega
• Shortened title: ACS omega
• Publisher: American Chemical Society
• ISSN: 2470-1343
• COBISS.SI-ID: 525873945

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: renij, organorenijevi(I) trikarbonilni kompleksi, piridinski ligandi