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Photochemistry and Redox Chemistry of an Unsymmetrical Bimetallic Copper(I) Complex
2016
The bimetallic copper(I) complex Cu2L2 (cis-1) is formed with high diasteroselectivity from [Cu(NCCH3)4][BF4] and HL (4-tert-butyl phenyl(pyrrolato-2-yl-methylene)amine) in a kinetically controlled reaction. cis-1 features a rather short Cu···Cu distance of 2.4756(6) A and is weakly emissive at room temperature in solution. Oxidatively triggered disproportionation of cis-1 yields elemental copper and the mononuclear copper(II) complex CuL2 (trans-2). One-electron reduction of trans-2 gives cuprate [2]– with a bent bis(pyrrolato) coordinated copper(I) entity. The imine donor atoms of [2]– can insert an additional copper(I) ion giving exclusively the bimetallic complex cis-1 closing the oxida…
On the Road to MM′X Polymers: Redox Properties of Heterometallic Ni···Pt Paddlewheel Complexes
2014
On the quest of heterometallic mixed-valence MM'X chains, we have prepared two stable discrete bimetallic compounds: the reduced (PPN)[ClNi(μ-OSCPh)4Pt] (PPN = bis(triphenylphosphine)iminium; OSCPh = benzothiocarboxylato) and the oxidized [(H2O)Ni(μ-OSCPh)4PtCl] species. The role of the aqua and chlorido axial ligands is crucial to facilitate oxidation of the {Ni(μ-OSCPh)4Pt} core. Experimental and theoretical analyses indicate that a NiPt-Cl/Cl-NiPt isomerization process occurs in the oxidized species. The electronic structure of the reduced system shows two unpaired electrons, one located in a d(x(2)-y(2)) orbital of the Ni(II) ion and a second in the antibonding d(z(2)-dz(2)) combination…
Hybrid Molecular Materials Based upon Magnetic Polyoxometalates and Organic π-Electron Donors: Syntheses, Structures, and Properties of Bis(ethylene…
1998
International audience; The syntheses, crystal structures, and physical properties of the series of radical salts made with bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or ET) and monosubstituted α-Keggin polyoxoanions of formula [XZ(H2O)M11O39]5- (XZM11 = Si(IV)Fe(III)Mo11, Si(IV)Cr(III)W11, P(V)Con(II)W11, P(V)Ni(II)W11, P(V)Cu(II)W11 P(V)Zn(II)W11, P(V)Mn(II)W11, and P(V)Mn(II)Mo11) containing a magnetic metal ion Z on a peripheral octahedral site of the Keggin union are reported. They all crystallize in two related series called α2 and α3. The general structure consists of alternating layers of the organic donor and the Keggin polyoxometalates. While the stoichiometry and α-packing a…
A decacobalt(ii) cluster with triple-sandwich structure obtained by partial reductive hydrolysis of a pentacobalt(ii/iii) Weakley-type polyoxometalat…
2016
Partial reductive hydrolysis of a penta-CoII/III cluster [CoII4(H2O)2(CoIIIW9O34)(PW9O34)]12− (1) leads to the formation of [Co2{Co3(H2O)(Co(OH)2W7O26)(PW9O34)}2]22− (2). This polyoxometalate is made up of two capping [PW9O34]9− units and two bridging [W7O26]10− units that assemble to encapsulate a novel deca-CoII cluster core comprising octahedral and tetrahedral CoII ions.
Electrochemical instability of highly fluorinated tetraphenyl borates and syntheses of their respective biphenyls
2018
Highly fluorinated tetraphenyl borate anions are of importance as weakly coordinating anions in metalorganic reactions. However, at high positive potentials their electrochemical stability in organic solvents is not sufficient. This was investigated by a comprehensive cyclic voltammetry study and can be used synthetically to generate highly fluorinated biphenyls.
Electrochemical, Spectroelectrochemical, and Structural Studies of Mono- and Diphosphorylated Zinc Porphyrins and Their Self-Assemblies
2019
International audience; Three series of porphyrins containing a Zn(II) central metal ion and zero, one or two phosphoryl groups at the meso-positions of the macrocycle were characterized as to their electrochemical, spectroscopic and structural properties in non-aqueous media. The investigated compounds are represented as 5,15-bis(4'-R-phenyl)porphyrinatozinc, 10-(diethoxyphosphoryl)-5,15-bis(4'-R-phenyl)porphyrinatozinc and 5,15-bis(diethoxyphosphoryl)-10,20-bis(4'-R-phenyl)porphyrinatozinc, where R = OMe, Me, H or CN. Linear-free energy relationships are observed between the measured redox potentials at room temperature and the electronic nature of the substituents at the 5 and 15 meso-ph…
Localization of alkali metal ions in sodium-promoted palladium catalysts as studied by low energy ion scattering and transmission electron microscopy
1996
Three series of palladium-based catalysts have been studied by Low Energy Ion Scattering (LEIS) and Transmission Electron Microscopy (TEM). The first series is comprised of Na-Pd/SiO{sub 2} catalysts, obtained by addition of palladium to a silica support and by further addition of sodium ions with a Na/Pd atomic ratio (R) equal to 0,6.4 and 25.6. The second series consists of palladium catalysts supported on natural pumice, in which, due to a different loading of supported palladium, R{prime}, the (Na+K)/Pd atomic ratio, is equal to 17.0 and 39.4. The third series is represented by two palladium-based catalysts supported on {open_quotes}model pumices,{close_quotes} synthetic silico-aluminat…
The nature of interactions of benzene with CF3I and CF3CH2I
2019
In situ grown crystals of CF3I and CF3CH2I are dominated by I⋯I and F⋯F interactions. Their co-crystals with benzene, (CF3I)2·C6H6 and CF3CH2I·C6H6, contain two completely different sets of intermolecular interactions. (CF3I)2·C6H6 shows a unique halogen-bond type: above-the-bond C–I⋯πC6H6 interactions. CF3CH2I·C6H6 shows above-the-centre C–H⋯πC6H6 interactions. These interactions are electrostatically dominated type II halogen bonds between single halogenoalkane molecules and weaker dispersion dominated interactions between the co-crystal components. The observed preferences for benzene for the two binding partners match with calculated molecular electrostatic potentials.
An investigation of photo- and pressure-induced effects in a pair of isostructural two-dimensional spin-crossover framework materials
2014
International audience; Two new isostructural iron(II) spin-crossover (SCO) framework (SCOF) materials of the type [Fe(dpms)2 (NCX)2 ] (dpms=4,4'-dipyridylmethyl sulfide; X=S (SCOF-6(S)), X=Se (SCOF-6(Se))) have been synthesized. The 2D framework materials consist of undulating and interpenetrated rhomboid (4,4) nets. SCOF-6(S) displays an incomplete SCO transition with only approximately 30 % conversion of high-spin (HS) to low-spin iron(II) sites over the temperature range 300-4 K (T1/2 =75 K). In contrast, the NCSe(-) analogue, SCOF-6(Se), displays a complete SCO transition (T1/2 =135 K). Photomagnetic characterizations reveal quantitative light- induced excited spin-state trapping (LIES…
Theoretical search for very short metal-actinide bonds: NUIr and isoelectronic systems.
2004
, respectively. These analogues provide anexample ofthe isolobal principle, now without any outsideligands onthePt atom,asituation describedasits “autogenicisolobality”. These systems have multiple C Pt bonds. Theisolobal principle of Hoffmann refers to the similar chemicalbehaviorofansphybridandametalatomwithligands,-ML