👤 Fabbiani FP

Title: Exploring the in vitro anticancer activities of Re(I) picolinic acid and its fluorinated complex derivatives on lung cancer cells: a structural study. Abstract: Fifteen rhenium(I) tricarbonyl complexes of the form fac-[Re(N,O')(CO)3(X)], where N,O'-bidentate ligand = 2-picolinic acid (Pico); 3,5-difluoropyridine-2-carboxylic acid (Dfpc); 3-trifluoromethyl-pyridine-2-carboxylic acid (Tfpc) and X = H2O; pyrazole (Pz); pyridine (Py); imidazole (Im); and methanol (CH3OH) were synthesized using the '2 + 1' mixed ligand approach with an average yield of 84%. The complexes were characterized using the following spectroscopic techniques: IR, 1H and 13C NMR, UV/Vis, and single-crystal X-ray diffraction. The effect of the fluorine atoms on the backbone of the N,O'-bidentate ligand was investigated and a trend was noticed in the carbonyl stretching frequencies: with Pico < Tfpc < Dfpc. The in vitro biological screening on Vero (healthy mammalian), HeLa (cervical carcinoma) and A549 (lung cancer) cells revealed one toxic complex, fac-[Re(Pico)(CO)3(H2O)], with respective LC50 values of 9.0 ± 0.9, 15.8 ± 4.9 (SI = 0.570) and 20.9 ± 0.8 (SI = 0.430) μg/mL. As a result, it can be used as a positive control drug of toxicity. Show less

The synthesis and characterization of ruthenium(II) arene complexes of the general formula [(eta(6)-arene)Ru(XY)Z](+), where arene = p-cymene (p-cym), hexamethylbenzene (hmb), or biphenyl (bip), XY = o-phenylenediamine (o-pda), o-benzoquinonediimine (o-bqdi), or 4,5-dimethyl-o-phenylenediamine (dmpda), and Z = Cl, Br, or I, are reported (complexes 1-6). In addition, the X-ray crystal structures of [(eta(6)-p-cym)Ru(o-pda)Cl]PF(6) (1) and [(eta(6)-hmb)Ru(o-bqdi)Cl]PF(6) (3PF(6)) are described. The Ru-N distances in 3PF(6) are significantly shorter [2.033(4) and 2.025(4) A] compared to those in 1 [2.141(2) and 2.156(2) A]. All of the imine complexes (3-5) exhibit a characteristic broad (1)H NMR NH resonance at ca. delta 14-15. Complex 1 undergoes concomitant ligand-based oxidation and hydrolysis (38% after 24 h) in water. The oxidation also occurs in methanol. The iodido complex [(eta(6)-p-cym)Ru(o-bqdi)I]I (4) did not undergo hydrolysis, whereas the chlorido complex 3 showed relatively fast hydrolysis (t(1/2) = 7.5 min). Density functional theory calculations showed that the total bonding energy of 9-EtG in [(eta(6)-p-cym)Ru(o-pda)(9-EtG-N7)](2+) (1EtG) is 23.8 kJ/mol lower than that in [(eta(6)-p-cym)Ru(o-bqdi)(9-EtG-N7)](2+) (3EtG). The greater bonding energy is related to the contribution from strong hydrogen bonding between the NH proton of the chelating ligand and O6 of 9-EtG (1.69 A). A loss of cytotoxic activity was observed upon oxidation of the amine ligand to an imine (e.g., IC(50) = 11 microM for 1 and IC(50) > 100 microM for 3, against A2780 ovarian cancer cells). The relationship between the cytotoxic activity and the solution and solid state structures of the imine and amine complexes is discussed. Show less

We report structure-activity relationships for organometallic RuII complexes of the type [(eta6-arene)Ru(XY)Cl]Z, where XY is an N,N- (diamine), N,O- (e.g., amino acidate), or O,O- (e.g., beta-diketonate) chelating ligand, the arene ranges from benzene derivatives to fused polycyclic hydrocarbons, and Z is usually PF6. The X-ray structures of 13 complexes are reported. All have the characteristic "piano-stool" geometry. The complexes most active toward A2780 human ovarian cancer cells contained XY=ethylenediamine (en) and extended polycyclic arenes. Complexes with polar substituents on the arene or XY=bipyridyl derivatives exhibited reduced activity. The activity of the O,O-chelated complexes depended strongly on the substituents and on the arene. For arene=p-cymene, XY=amino acidate complexes were inactive. Complexes were not cross-resistant with cisplatin, and cross-resistance to Adriamycin was circumvented by replacing XY=en with 1,2-phenylenediamine. Some complexes were also active against colon, pancreatic, and lung cancer cells. Show less