Chiroptical and magnetic properties of star-shaped Fe-4(III) complexes from chiral Schiff bases. Structural and magnetic correlations based on continuous shape measures

New chiral Fe-4(III) star-shaped complexes have been synthesized starting from enantiomerically pure Schiff bases and chiroptically and magnetically characterized. The structural and magnetic properties of the complete family of 40 Fe-4 complexes reported in the literature have been analyzed in the search for synthetic and magnetostructural correlations

DNA interaction and cytotoxicity studies of new ruthenium(II) cyclopentadienyl derivative complexescontaining heteroaromatic ligands

Four ruthenium(II) complexes with the formula [Ru(eta(5)-C(5)H(5))(PP)L][CF(3)SO(3)], being (PP = two triphenylphosphine molecules), L = 1-benzylimidazole, 1; (PP = two triphenylphosphine molecules), L = 2,2'bipyridine, 2; (PP = two triphenylphosphine molecules), L = 4-Methylpyridine, 3; (PP = 1,2-bis(diphenylphosphine) ethane), L = 4-Methylpyridine, 4, were prepared, in view to evaluate their potentialities as antitumor agents. The compounds were completely characterized by NMR spectroscopy and their crystal and molecular structures were determined by X-ray diffraction. Electrochemical studies were carried out giving for all the compounds quasi-reversible processes. The images obtained by atomic force microscopy (AFM) suggest interaction with pBR322 plasmid DNA. Measurements of the viscosity of solutions of free DNA and DNA incubated with different concentrations of the compounds confirmed this interaction. The cytotoxicity of compounds 1234 was much higher than that of cisplatin against human leukemia cancer cells (HL-60 cells). IC(50) values for all the compounds are in the range of submicromolar amounts. Apoptotic death percentage was also studied resulting similar than that of cisplatin. (C) 2010 Elsevier Inc. All rights reserved

Determination of ZFS parameters from the EPR spectra of mono-, di- and trinuclear Mn II complexes: impact of magnetic coupling

International audienc

Singlet ground states in compounds with a [MnIII4O 2 ] 8+ core due to broken degeneration

International audienc

Organocatalytic enantioselective pyrazol-3-one addition to maleimides: reactivity and stereochemical course

The enantioselective synthesis of pyrazol-3-ones has not been extensively studied in organic synthesis. Here in we report the first asymmetric addition of pyrazolones to maleimides catalyzed by bifunctional thiourea catalysts

Dinuclear Ln III Complexes with 9-Anthracenecarboxylate Showing Field-Induced SMM and Visible/NIR Luminescence

International audienc

Reactivity in polynuclear transition metal chemistry as a means to obtain high-spin molecules: substitution of mu(4)-OH- by eta 1,mu(4)-N-3(-) increases nine times the ground-state S value of a nonanuclear nickel(II) cage

The reaction of di-2-pyridyl ketone, (2-py)(2)CO, with Ni(O2CMe)(2). 4H(2)O yields the cage [Ni-9(OH)(2)(O2CMe)(8)(2-py) 2CO2(4)], which reacts further with N-3(-) ions to give the structurally similar cluster [Ni-9(N-3)(2)(O2CMe)(8)(2-py) 2CO2(4)] containing extremely rare eta (1),mu (4)-N-3(-) groups; magnetic studies reveal that the spin ground state of the latter is nine times the ground state of the former

New ternary complexes of copper(II) with 2,2 `-bipyridine (Bpy) and phosphocholine (PCh(-)) or the quaternary 1-(2-phosphonomethoxy)ethyl derivative of 2,4-diaminopyrimidine (PMEDAPy(-))

The polynuclear Cu-II complexes [Cu4Cl2 (bpy)(4)(PCh(-))(2)] (ClO4)(4)center dot H2O (1) and [Cu-6(bpy)(6)(PMEAPy(-))(4)](ClO4)(8)center dot 2H(2)O (2), where bpy = 2,2`-bipyridine, PCh(-) = phosphocholine ([2-(phosphonooxy)ethyl]trimethylammonium) and PMEDAPy(-) = 1-[2(phosphonomethoxy) ethyl]-2,4-diaminopyrimidine, have been synthesized and characterized by X-ray single-crystal analysis. Compound 1 crystallizes in the triclinic system (P-1 space group) and consists of tetranuclear Cu-II units, which are threefoldly bridged by mu(3)-O, O`, O``-phosphate groups in a square arrangement around the copper atoms. Complex 2 crystallizes in the monoclinic system (P2(1)/c space group) and consists of hexanuclear Cu-II units containing the same kind of mu(3)-phosph(on)ate bridges like 1 and in addition mu(4)-O, O`, O`` -phosphonate bridges. The topology of compound 2 can be envisaged as two triangular subunits linked by means of a double Cu–O–Cu bridge provided by the μ4-phosphonate unit. Magnetic susceptibility measurements of the two complexes in the temperature range of 2–300 K show weak antiferromagnetic couplings mediated by the phosph(on)ate bridges

Easy synthesis of 7-alkylbicyclo[3.3.1]non-6-en-3-ones by silica gel-promoted fragmentation of 3-alkyl-2-oxaadamant-1-yl mesylates

A synthesis of 7-alkylbicyclo[3.3.1]non-6-en-3-ones4b-f and 4j, k by reaction of the corresponding 3-alkyl-2-oxaadamant-1-yl mesylates3 with silica gel in methylene chloride at room temperature, is described. The method failed to give enones4a, g and the related compounds4l, m, what can be rationalized on mechanistic grounds. The synthesis of several bicyclic enones4 from the readily available diketones1a-c [X = CH2, (CH3O)2C, (CH3O)(CH3)C] via the corresponding oxaadamantanols2 and mesylates3, is described