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- Novel ruthenium methylcyclopentadienyl complex bearing a bipyridine perfluorinated ligand shows strong activity towards colorectal cancer cellsPublication . Teixeira, Ricardo G.; Brás, Ana Rita; Côrte-Real, Leonor; Tatikonda, Rajendhraprasad; Sanches, Anabela; Robalo, Maria Paula; Avecilla, Fernando; Moreira, Tiago; Garcia, M. Helena; Haukka, Matti; Preto, Ana; Valente, AndreiaThree new compounds have been synthesized and completely characterized by analytical and spectroscopic techniques. The new bipyridine-perfluorinated ligand L1 and the new organometallic complex [Ru(eta(5)-MeCp)(PPh3)(2)Cl] (Ru1) crystalize in the centrosymmetric triclinic space group P (1) over bar. Analysis of the phenotypic effects induced by both organometallic complexes Ru1 and [Ru(eta(5)-MeCp)(PPh3)(L1)] [CF3SO3] (Ru2), on human colorectal cancer cells (SW480 and RKO) survival, showed that Ru2 has a potent anti-proliferative activity, 4-6 times higher than cisplatin, and induce apoptosis in these cells. Data obtained in a noncancerous cell line derived from normal colon epithelial cells (NCM460) revealed an intrinsic selectivity of Ru2 for malignant cells at low concentrations, showing the high potential of this compound as a selective anticancer agent. (C) 2017 Elsevier Masson SAS. All rights reserved.
- Complexes of copper(II) with 3-(ortho-substituted phenylhydrazo)pentane-2,4-diones: syntheses,properties and catalytic activity for cyclohexane oxidationPublication . Kopylovich, Maximilian N.; Nunes, Andreia C. C.; Mahmudov, Kamran; Haukka, Matti; Mac Leod, Tatiana C. O.; Martins, Luisa; Kuznetsov, Maxim L.; Pombeiro, ArmandoReactions of copper(II) with 3-phenylhydrazopentane-2,4-diones X-2-C6H4-NHN = C{C(= O)CH3}(2) bearing a substituent in the ortho-position [X = OH (H2L1) 1, AsO3H2 (H3L2) 2, Cl (HL3) 3, SO3H (H2L4) 4, COOCH3 (HL5) 5, COOH (H2L6) 6, NO2 (HL7) 7 or H (HL8) 8] lead to a variety of complexes including the monomeric [CuL4(H2O)(2)]center dot H2O 10, [CuL4(H2O)(2)] 11 and [Cu(HL4)(2)(H2O)(4)] 12, the dimeric [Cu-2(H2O)(2)(mu-HL2)(2)] 9 and the polymeric [Cu(mu-L-6)](n)] 13 ones, often bearing two fused six-membered metallacycles. Complexes 10-12 can interconvert, depending on pH and temperature, whereas the Cu(II) reactions with 4 in the presence of cyanoguanidine or imidazole (im) afford the monomeric compound [Cu(H2O)(4){NCNC(NH2)(2)}(2)](HL4)(2)center dot 6H(2)O 14 and the heteroligand polymer [Cu(mu-L-4)(im)](n) 15, respectively. The compounds were characterized by single crystal X-ray diffraction (complexes), electrochemical and thermogravimetric studies, as well as elemental analysis, IR, H-1 and C-13 NMR spectroscopies (diones) and ESI-MS. The effects of the substituents in 1-8 on the HOMO-LUMO gap and the relative stability of the model compounds [Cu(OH)(L-8)(H2O)]center dot H2O, [Cu(L-1)(H2O)(2)]center dot H2O and [Cu(L-4)(H2O)(2)]center dot H2O are discussed on the basis of DFT calculations that show the stabilization follows the order: two fused 6-membered > two fused 6-membered/5-membered > one 6-membered metallacycles. Complexes 9, 10, 12 and 13 act as catalyst precursors for the peroxidative oxidation (with H2O2) of cyclohexane to cyclohexanol and cyclohexanone, in MeCN/H2O (total yields of ca. 20% with TONs up to 566), under mild conditions.
- Rhenium complexes of tris(pyrazolyl)methanes and sulfonate derivativePublication . Alegria, Elisabete; Martins, Luisa; Haukka, Matti; Pombeiro, ArmandoThe trioxo [ReO3{SO3C(pz)3}] (1) (pz = pyrazolyl) and oxo [ReOCl{SO3C(pz)3}(PPh3)]Cl (2) compounds with tris(pyrazolyl)methanesulfonate were obtained by treatment of Re2O7 or [ReOCl3(PPh3)2], respectively, with Li[SO3C(pz)3], whereas [ReCl3{HC(pz)3}] (3), [ReCl3{HC(3,5-Me2pz)3}] (4) and [ReCl4{η2-HC(pz)3}] (5) were prepared by reaction of [ReOCl3(PPh3)2] (3,4) or [ReCl4(NCMe)2] (5) with hydrotris(pyrazolyl)methane HC(pz)3 (3,5) or hydrotris(3,5-dimethyl-1-pyrazolyl)methane HC(3,5-Me2pz)3 (4). [ReO{SO3C(pz)3}{OC(CH3)2pz}][ReO4] 6, with a chelated pyrazolyl-alkoxide, was derived from an unprecedented ketone-pyrazolyl coupling on reaction of crude 1 with acetone. The compounds have been characterized by elemental analyses, IR and NMR spectroscopies, FAB-MS spectrometry and cyclic voltammetry and, in the case of 5 and 6, also by single-crystal X-ray diffraction. The electrochemical EL Lever parameter has been estimated, for the first time, for the SO3C(pz)3− and oxo ligands allowing the measurement of their electron-donor character and comparison with other ligands. Compounds 1, 2 and 6 appear to be the first tris(pyrazolyl)methanesulfonate complexes of rhenium to be reported.