Search results for "ELEMENT"
showing 10 items of 13601 documents
New, Multi‐Dimensional Cu(tn)‐[M(CN) 6 ] n – Cyano‐Bridged, Bimetallic Coordination Materials (M = Fe II , Co III , Cr III and tn = 1,3‐Diaminopropan…
2005
Reaction of the [Fe I I I (CN) 6 ] 3 - anion with [Cu I I (tn)(H 2 O) n ] 2 + (tn = 1,3-diaminopropane) affords the compounds [{Cu I I (tn)} 2 -{Fe I I (CN) 6 }].KCl.5H 2 O (1), [(Cu"(tn))2(Fe"(CN) 6 )].4H 2 O (2), and [{Cu I I (tnH) 2 (H 2 O) 2 }{Fe I I (CN) 6 }].2H 2 O (3). Each iron center in 1 and 2 is linked to six copper(II) ions by six cyanide bridges, while each copper ion is linked to three equivalent iron(II) ions. Despite these resemblances, the two compounds present large structural differences caused by two different orientations of the Cu-NC-Fe bridges: compound 1 has a 2D structure which can be described as successions of "Cu 4 Fe 3 " defective cubane units, while compound 2 …
Highly antiproliferative neutral Ru(ii)-arene phosphine complexes
2018
Six ruthenium(II)- and four gold(I)-phosphine based complexes were synthesized and fully characterized. Some of them displayed strong antiproliferative properties for several types of cancer including colon, breast, and lung. Notably, two of the Ru(II) complexes displayed an IC50 of around 2 μM, which is exceptional for these types of complexes. The dramatic impact of the nature of the arene coordinated on the ruthenium center was clearly evidenced.
Magneto-structural correlations in asymmetric oxalato-bridged dicopper(II) complexes with polymethyl-substituted pyrazole ligands
2018
Two oxalato-bridged dinuclear copper(II) complexes, [{Cu(Hdmpz)3}2(μ-ox)](ClO4)2·2H2O (1) and [{Cu(Htmpz)3}2(μ-ox)](ClO4)2·2H2O (2) (Hdmpz = 3,5-dimethyl-1H-pyrazole and Htmpz = 3,4,5-trimethyl-1H-pyrazole), have been synthesized and structurally and magnetically characterized. The crystal structures of 1 and 2 consist of asymmetric bis-bidentate μ-oxalatodicopper(II) complex cations with two short [Cu–O = 1.976(2) (1) and 1.973(2) Å (2)] and two long copper–oxygen bonds [Cu–O = 2.122(2) (1) and 2.110(2) Å (2)]. The environment at each CuII ion in 1 and 2 is closer to the trigonal bipyramidal geometry than to the square pyramidal [τ = 0.633 (1) and 0.711 (2)]. The magnetic properties of 1 a…
Synthesis, crystal structure and magnetic properties of the cyclic tetranuclear compound [Cu4(pz)4(hppa)2(H2O)4] [pz = pyrazolate; hppa = R,S-2-hydro…
2019
Abstract The synthesis, X-ray structure and magnetic properties of the neutral tetranuclear copper(II) complex of formula [Cu4(pz)4(hppa)2(H2O)4] (1) [Hpz = pyrazole and hppa = R,S-2-hydroxo-2-phenyl-2-(1-pyrazolyl)acetate] are reported. Remarkably, the structure of 1 reveals the presence of the S- and R-forms of the new hppa ligand which is formed in situ in the complex reaction between copper(II), pyrazole and phenylmalonate in water:methanol solvent mixture under ambient conditions. The two crystallographically independent copper(II) ions [Cu(1)/Cu(2)] are five-coordinate in square pyramidal surroundings. Three nitrogen atoms, from two pz groups and one hppa ligand and one oxygen atom of…
DFT Study on the Interaction of Tris(benzene-1,2-dithiolato)molybdenum Complex with Water. A Hydrolysis Mechanism Involving a Feasible Seven-Coordina…
2016
In the present work, the reactivity of the tris(benzene-1,2-dithiolato)molybdenum complex ([Mo(bdt)3]) toward water is studied by means of the density functional theory (DFT). DFT calculations were performed using the M06, B3P86, and B3PW91 hybrid functionals for comparison purposes. The M06 method was employed to elucidate the reaction pathway, relative stability of the intermediate products, nature of the Mo–S bond cleavage, and electronic structure of the involved molybdenum species. This functional was also used to study the transference of electrons from the molybdenum center toward the ligands. The reaction pathway confirms that [Mo(bdt)3] undergoes hydrolysis, yielding dihydroxo-bis(…
Mono-DMSO ligated cobalt nitrophenylcorroles: electrochemical and spectral characterization
2018
Four mono-DMSO ligated cobalt corroles with one or three meso-nitrophenyl substituents on the macrocycle were synthesized and investigated as to their electrochemical and spectroscopic properties in CH2Cl2 and DMSO. Comparisons are made between redox reactions of the five-coordinate DMSO adducts in the current study and earlier examined five- and six-coordinate cobalt corroles with pyridine axial ligands which were characterized in a variety of nonaqueous electrochemical solvents. The binding of carbon monoxide (CO) is also investigated.
A reinvestigation of compound CpMo(PMe3)2(CH3)2: Alkylation by single electron transfer and radical addition?
2001
International audience; The synthesis of the half-sandwich molybdenum(III) diphosphine dimethyl complex CpMo(PMe3)2(CH3)2 has been reinvestigated. The compound was obtained from the corresponding dichloro complex CpMo(PMe3)2Cl2 and methyllithium at low temperatures and isolated as a crystalline product by conducting all operations at temperatures lower than −10 °C. The complex is thermally unstable at room temperature but has been fully characterised by EPR spectroscopy, cyclic voltammetry and X-ray diffraction. The formation reaction is retarded by excess phosphine. On the basis of this and other related observations, a mechanism involving phosphine pre-dissociation followed by single elec…
Theoretical investigation of the spin crossover transition states of the addition of methane to a series of Group 6 metallocenes using minimum energy…
2016
International audience; Density functional calculations are reported on the addition of methane to Group 6 metallocenes, M(η-C5H5)2 (M), M(CH2(η-C5H4)2) (a-M) and M(η-C5Me5)2 (M*) where M = Mo and W. Full geometry optimisations were carried out on the singlet and triplet 16 electron complexes, 1[M] and 3[M], the η2-methane complexes, 1[M(η2-CH4)], and the hydridomethyl adducts, 1[M(CH3)(H)]. The triplet state for [M] was found to be more stable for all six metallocenes, the difference being least in the case of the ansa-bridged system. Formation of the hydridomethyl complexes was exoenergetic for all tungsten systems and for a-Mo, the other two Mo systems being endoenergetic. Minumum energy…
Cobalt Clusters with Cubane-Type Topologies Based on Trivacant Polyoxometalate Ligands.
2016
Four novel cobalt-substituted polyoxometalates having cobalt cores exhibiting cubane or dicubane topologies have been synthesized and characterized by IR, elemental analysis, electrochemistry, UV-vis spectroscopy, X-ray single-crystal analysis, and magnetic studies. The tetracobalt(II)-substituted polyoxometalate [Co4(OH)3(H2O)6(PW9O34)](4-) (1) consists of a trilacunary [B-α-PW9O34](9-) unit which accommodates a cubane-like {Co(II)4O4} core. In the heptacobalt(II,III)-containing polyoxometalates [Co7(OH)6(H2O)6(PW9O34)2](9-) (2), [Co7(OH)6(H2O)4(PW9O34)2]n(9n-) (3), and [Co7(OH)6(H2O)6(P2W15O56)2](15-) (4), dicubane-like {Co(II)6Co(III)O8} cores are encapsulated between two heptadentate [B…
Reactivity of di-n-butyl-dicyclopentadienylzirconium towards amido stabilized stannylenes
2009
Abstract Reaction of Sn[(N(C 6 H 3 i Pr 2 -2,6)(SiMe 3 )] 2 and [{Sn(N(C 6 H 3 i Pr 2 -2,6)(SiMe 3 )(μ-Cl) 2 ] with di- n -butyl-dicyclopentadienylzirconium yielded the trimetallic a carbene-like complex {[(N(C 6 H 3 i Pr 2 -2,6)(SiMe 3 )]( n -Bu)Sn} 2 Cp 2 Zr. The oxidation of {[(N(C 6 H 3 i Pr 2 -2,6)(SiMe 3 )]( n -Bu)Sn} 2 Cp 2 Zr by oxygen gives the five-membered dioxadistannazirconacyclic complex {[(N(C 6 H 3 i Pr 2 -2,6)(SiMe 3 )]( n -Bu)Sn} 2 O 2 Cp 2 Zr.