Search results for "rganometallic compounds"

Cubane-Type Mo3FeS44+,5+ Complexes Containing Outer Diphosphane Ligands: Ligand Substitution Reactions, Spectroscopic Studies, and Electronic Structu…

2012

A general protocol to access Mo(3)FeS(4)(4+) clusters selectively modified at the Fe coordination site is presented starting from the all-chlorine Mo(3)(FeCl)S(4)(dmpe)(3)Cl(3) (1) [dmpe = 1,2-bis(dimethylphosphane-ethane)] cluster and tetrabutylammonium salts (n-Bu(4)NX) (X = CN(-), N(3)(-), and PhS(-)). Clusters Mo(3)(FeX)S(4)(dmpe)(3)Cl(3) [X = CN(-) (2), N(3)(-) (3), and PhS(-) (4)] are prepared in high yield, and comparison of geometric and redox features upon modification of the coordination environment at the Fe site at parity of ligands at the Mo sites is also presented. The existence of the cubane-type Mo(3)FeS(4)(4+,5+) redox couple is demonstrated by cyclic voltammetry and for co…

Stepwise sequential redox potential modulation possible on a single platform.

2011

Step by step: The cluster [3,3'-Co(1,2-C(2)B(9)H(11))(2)](-) is an excellent platform for making a stepwise tunable redox potential system by dehydroiodination. With the addition of up to eight iodine substituents (purple; see picture), there is a fall in the E(1/2)(Co(III)/Co(II)) value from -1.80 V to -0.68 V (vs. Fc(+)/Fc; Fc = ferrocene). A practical application of this tunability has been observed in the growth of polypyrrole.

Expanding the 2, 2’-bipyrimidine bridged 1D homonuclear coordination polymers family: [MIIbpymCl2] (M=Fe, Co) magnetic and structural characterization

2013

One pot reaction of hydrated chloride salts of Fe(II) and Co(II) with stoichiometric amounts of 2, 2’-bipyrimidine (bpym) in a methanol/ acetonitrile mixture afforded the corresponding 1D homonuclear coordination polymers, [μ-(bpym)MCl2]n. Crystal structures of both complexes are isomorphous in the highly symmetric orthorhombic space group Fddd. The 1D coordination polymers are composed of almost orthogonal alternating bipyrimidine bridges linking the {MCl2} units. The magnetic behaviour of the Fe(II)compound can be well understood as a uniform S=2 chain with antiferromagnetic exchange interaction between metal ion sites. In the case of the Co(II) ion, also an antiferromagnetic interaction …

Exploring the redox reactivity of magnesium porphine. Insight into the origins of electropolymerisation.

2010

International audience; Magnesium(II) porphine, MgP (1), was synthesised according to the Lindsey procedure allowing to isolate and crystallise 1-formyldipyrromethane (2) as a synthetic intermediate. Unprecedented Xray diffraction studies revealed multiple intermolecular associations in the crystal between neighbouring units of 2, namely hydrogen bond and CH … π. The electrochemical behaviour of 1 was examined by means of cyclic voltammetry. In oxydation, two well-defined and distinct steps are assigned to macrocycle concerned electron transfers yielding initially the π-cation radical and π dication, respectively. The highly reactive dication condenses neutral magnesium porphine to form a d…

Electrochemical synthesis and structural characterization of Co(II), Ni(II) and Cu(II) complexes of N,N-bis(4,5-dimethyl-2-hydroxybenzyl)-N-(2-pyridy…

2009

The electrochemical oxidation of anodic metal (cobalt, nickel or copper) in a cell containing an acetonitrile solution of the ligand N,N-bis(4,5-dimethyl-2-hydroxybenzyl)-N-(2-pyridylmethyl)amine (H2L) affords complexes [Co2L2].H2O (1), [Ni3L3] (2) and [Cu2L2] 3H2O (4). On using nickel as the anode and the addition to the solution electrolytic phase of the amount of water necessary to saturate the solution, the electrolytic process gave rise to the new compound [Ni2L2(H2O)1.5].CH3CN (3). Compounds 1 and 4 are dimeric and the metal atoms are pentacoordinated. Compound 3 also consists of dimeric neutral molecules with the nickel atoms in both penta- and hexacoordinated environments. The cryst…

Hydrogen and Copper Ion Induced Molecular Reorganizations in Two New Scorpiand-Like Ligands Appended with Pyridine Rings

2010

The synthesis of two new ligands constituted of a tris(2-aminoethyl)amine moiety linked to the 2,6 positions of a pyridine spacer through methylene groups in which the hanging arm is further functionalized with a 2-pycolyl (L1) or 3-pycolyl (L2) group is presented. The protonation of L1 and L2 and formation of Cu(2+) complexes have been studied using potentiometric, NMR, X-ray, and kinetic experiments. The results provide new information about the relevance of molecular movements in the chemistry of this kind of so-called scorpiand ligand. The comparison between these two ligands that only differ in the position of the substituent at the arm reveals important differences in both thermodynam…

Use of a reduced Schiff-Base ligand to prepare novel chloro-bridged chains of rare Cu(II) trinuclear complexes with mixed azido/oxo and chloro/oxo br…

2010

Two mixed bridged one-dimensional (1D) polynuclear complexes, [Cu(3)L(2)(mu(1,1)-N(3))(2)(mu-Cl)Cl](n) (1) and {[Cu(3)L(2)(mu-Cl)(3)Cl].0.46CH(3)OH}(n) (2), have been synthesized using the tridentate reduced Schiff-base ligand HL (2-[(2-dimethylamino-ethylamino)-methyl]-phenol). The complexes have been characterized by X-ray structural analyses and variable-temperature magnetic susceptibility measurements. In both complexes the basic trinuclear angular units are joined together by weak chloro bridges to form a 1D chain. The trinuclear structure of 1 is composed of two terminal square planar [Cu(L)(mu(1,1)-N(3))] units connected by a central Cu(II) atom through bridging nitrogen atoms of end…

Syntheses, structures, and magnetic properties of diphenoxo-bridged Cu(II)Ln(III) and Ni(II)(low-spin)Ln(III) compounds derived from a compartmental …

2010

Syntheses, characterization, and magnetic properties of a series of diphenoxo-bridged discrete dinuclear M(II)Ln(III) complexes (M = Cu or Ni, Ln = Ce-Yb) derived from the compartmental Schiff base ligand, H(2)L, obtained on condensation of 3-ethoxysalicylaldehyde with trans-1,2-diaminocyclohexane, are described. Single crystal X-ray structures of eight Cu(II)Ln(III) compounds (Ln = Ce (1), Pr (2), Nd (3), Sm (4), Tb (7), Ho (9), Er (10), and Yb (12)) and three Ni(II)Ln(III) (Ln = Ce (13), Sm (16), and Gd (18)) compounds have been determined. Considering the previously reported structure of the Cu(II)Gd(III) (6) compound (Eur. J. Inorg. Chem. 2005, 1500), a total of twelve structures are di…

Molecular Lead Clusters?From Unexpected Discovery to Rational Synthesis

2004

Multinuclear Cytotoxic Metallodrugs: Physicochemical Characterization and Biological Properties of Novel Heteronuclear Gold-Titanium Complexes

2011

An unprecedented series of titanocene-gold bi- and trimetallic complexes of the general formula [[(η(5)-C(5)H(5))(μ-η(5):κ(1)-C(5)H(4)(CH(2))(n)PPh(2))TiCl(2)](m)AuCl(x)](q+) (n = 0, 2, or 4; m = 1, x = 1, q = 0 or m = 2, x = 0, q = 1) have been prepared and characterized spectroscopically. The luminescence spectroscopy and photophysics of one of the compounds, [[(η(5)-C(5)H(5))(μ-η(5):κ(1)-C(5)H(4)PPh(2))TiCl(2)](2)Au]PF(6), have been investigated in 2MeTHF solution and in the solid state at 77 and 298 K. Evidence for interfragment interactions based on the comparison of electronic band positions and emission lifetimes, namely, triplet energy transfer (ET) from the Au- to the Ti-containing…