A relationship between pKa values, binding abilities to copper(ii) and iron(iii) and anticancer activity of 8-hydroxyquinoline derived Mannich bases.

New generations of Hoveyda and bis‐carbene type of ruthenium‐based olefin metathesis catalysts (10 and 12), containing cationic cyclic alkyl amino carbene (CAAC) ligands, have been synthetized. The catalysts show exceptional stability and activity in environmentally benign, protic media. Various olefin metatheses reactions of OH functionalized feedstock (e. g. RCM, ROMP CM) can be carried out at as low as 0.05 mol % catalyst loading in methanol, isopropanol, water or methanol/water solvent mixture, accomplishing the lowest applied catalyst loading reported so far in these media. The facile olefin metathesis of renewable feedstocks including phospholipids (23) and vegetable oils (20) in protic media has also been demonstrated.

Five Ru(II)( 6 -toluene) complexes formed with 2-picolinic acid and its various derivatives have been synthesized and characterized. X-ray structures of four complexes are also

Please cite this article as: J.P. Mészáros, J.M. Poljarevic, G.T. Gál, et al., Comparative solution and structural studies of half-sandwich rhodium and ruthenium complexes bearing curcumin and acetylacetone, Journal of Inorganic Biochemistry, https://doi.ABSTRACT Half-sandwich organometallic complexes of curcumin are extensively investigated as anticancer compounds. Speciation studies were performed to explore the solution stability of curcumin complexes formed with [Rh( 5 -C5Me5)(H2O)3] 2+ . Acetylacetone (Hacac), as the simplest -diketone ligand bearing (O,O) donor set, was involved for comparison and its Ru( 6 -p-cymene), Ru( 6 -toluene) complexes were also studied. 1 H NMR, UV-visible and pH-potentiometric titrations revealed a clear trend of stability constants of the acac complexes: Ru( 6 -p-cymene) > Ru( 6 -toluene) > Rh( 5 -C5Me5). Despite this order, the highest extent of complex formation is seen for the Rh( 5 -C5Me5) complexes at pH 7.4. Formation constant of [Rh( 5 -C5Me5)(H2curcumin)(H2O)] + reveals similar solution stability to that of the acac complex. Additionally, structures of two complexes were determined by Xray crystallography. The in vitro cytotoxicity of curcumin was not improved by the complexation with these organometallic cations. Highlights ► Solution stability of Ru(arene) and Rh(C5Me5) complexes of acac and curcumin ► Acac is used as curcumin binding model ► X-ray crystal structures of two complexes and comparison with analogous structures ► Antiproliferative activity against multidrug resistant human cancer cell lines ► Human serum albumin binding and interaction with cell culture medium components