catena-Poly[[chlorido(methyl phenyl sulfide-κS)mercury(II)]-μ-chlorido]

The title compound, [HgCl2(C7H8S)]n, was isolated from the reaction of MeSPh with HgCl2. The HgII atom has a distorted tetra­hedral geometry and is coordinated by one S atom and three Cl atoms. Two of the Cl atoms act as bridging ligands between the Hg atoms, forming a two-dimensional polymeric structure

Two-dimensional polymeric [Hg4(μ2-I)6I2(μ2-C4S6)]n

The title compound, poly[(μ2-2H,5H-1,3-dithiolo[4,5-d][1,3]di­thiole-2,5-dithione)hexa-μ2-iodido-diiodidotetra­mercury(II)], [Hg4I8(C4S6)]n, represents the first example of a coordination polymer assembled by the α,α-C4S6 dithione ligand. The HgII ions are four-coordinated in a distorted tetra­hedral geometry, the coordination demand being satisfied either by four bridging iodide ligands or by three iodide ligands (one terminal and two bridging) and a thio­carbonyl S atom. Due to the bridging nature of the dithione ligand, the coordination polymer has a two-dimensional structure, built up of undulated layers parallel to (001). There is an inversion center at the mid-point of the central C=C double bond

Somatostatin subtype-2 receptor-targeted metal-based anticancer complexes

Conjugates of a dicarba analogue of octreotide, a potent somatostatin agonist whose receptors are overexpressed on tumor cells, with [PtCl 2(dap)] (dap = 1-(carboxylic acid)-1,2-diaminoethane) (3), [(η 6-bip)Os(4-CO 2-pico)Cl] (bip = biphenyl, pico = picolinate) (4), [(η 6-p-cym)RuCl(dap)] + (p-cym = p-cymene) (5), and [(η 6-p-cym)RuCl(imidazole-CO 2H)(PPh 3)] + (6), were synthesized by using a solid-phase approach. Conjugates 3-5 readily underwent hydrolysis and DNA binding, whereas conjugate 6 was inert to ligand substitution. NMR spectroscopy and molecular dynamics calculations showed that conjugate formation does not perturb the overall peptide structure. Only 6 exhibited antiproliferative activity in human tumor cells (IC 50 = 63 ± 2 μ in MCF-7 cells and IC 50 = 26 ± 3 μ in DU-145 cells) with active participation of somatostatin receptors in cellular uptake. Similar cytotoxic activity was found in a normal cell line (IC 50 = 45 ± 2.6 μ in CHO cells), which can be attributed to a similar level of expression of somatostatin subtype-2 receptor. These studies provide new insights into the effect of receptor-binding peptide conjugation on the activity of metal-based anticancer drugs, and demonstrate the potential of such hybrid compounds to target tumor cells specifically. © 2012 American Chemical Society

Transition metal catalyzed element–element′ additions to alkynes

The efficient and stereoselective synthesis of, or precursors to, multi-substituted alkenes has attracted substantial interest due to their existence in various industrially and biologically important compounds. One of the most atom economical routes to such alkenes is the transition metal catalyzed hetero element–element′ π-insertion into alkynes. This article provides a thorough up-to-date review on this area of chemistry, including discussions on the mechanism, range of Esingle bondE′ bonds accessible and the stoichiometric/catalytic transition metal mediators employed

Comment entrer dans les mêmes savoirs en formation professionnelle ? Étude prospective de l’organisation de l’activité enseignante en comptabilité-gestion en France et au Gabon

International audienc

Construction of 1D and 2D Copper(I) Coordination Polymers Assembled by PhS(CH2)nSPh (n = 1,2) Dithioether Ligands: Surprising Effect of the Spacer Length on the Dimensionality, Cluster Nuclearity and the Fluorescence Properties of the Metal-Organic Framework

International audienceTreatment of CuI with PhSCH2SPh in MeCN solution affords, by a self‐assembly reaction, the monodimensional metal–organic coordination polymer [Cu4I4{μ‐PhS2CH2SPh}2]n (1), in which Cu4(μ3‐I)4 cluster units are linked by the dithioether ligand in a 1D necklace structure. In contrast, the reaction of PhSCH2CH2SPh with CuI results in the formation of the metallopolymer [(CuI)2{μ‐PhS(CH2)2SPh}2]n (2). The 2D network of 2 is built from dimeric Cu2I2 units which are connected by 1,2‐bis(phenylthio)ethane bridging ligands. The solid‐state luminescence spectrum of 1 exhibits a strong emission around 532 nm, whereas a weak emission centred at 413 nm is observed in the case of 2

1,1,2,2-tetramethyl-1,2-bis(phenylthiomethyl)disilane, a flexible ligand for the construction of macrocyclic, mesocyclic and bridged dithioether complexes. Synthesis of silylated olefins by catalytic bis-silylation of alkynes

International audienc

Formation of Extended 1D and 2D Coordination Polymers in Tetrathioether Complexes of Mercury (II) and Copper (I): Crystal Structures of [(Ge(CH2SPh)4)]HgBr2]n and [(Ge(CH2SPh)4)(Cu2I2)]n

International audienceA one-dimensional (1D) coordination polymer of stoichiometry [{{Ge(CH2SPh)4}HgBr2}n] (2b) has been prepared by treatment of HgBr2 with the functionalized germane Ge(CH2SPh)4 (1b), which is acting as a tetradentate thioether ligands. The extended structure results from weak intermolecular Hg–S interactions linking the monomeric {Ge(CH2SPh)4}HgBr2 units, as established using single-crystal X-ray diffraction. The effective coordination around the mercury atoms is best described as distorted octahedral. Upon reaction of CuI with 1b in a 2:1 metal-to-ligand ratio, the novel metal-organic polymer [{{Ge(CH2SPh)4}(Cu2I2)}n] (3), which incorporates rhombic dinuclear Cu(μ-I)2Cu units within its 2D sheet-like network, was obtained. The luminescence properties of 1b and 3 have been investigated both in solution and in the solid state. Upon treatment of 1b with [{Re(μ-Br)(CO)3(THF)}2] the mononuclear compound fac-[ReBr(CO)3{Ge(CH2SPh)4}] (4) is formed. In this chelate complex, two CH2SPh arms are ligated on ReI, the remaining two CH2SPh arms are dangling

Cyclopentadienyl Chemistry in Water: Synthesis and Properties of Bifunctionalized [(η5^5-C5_5H3_3{COOR}2_2)M(CO)3_3] (M = Re and 99m^{99m}Tc) Complexes

Complexes of the [(η5-C5H4COOR)M(CO)3] type (M = 99mTc, Re; R = targeting function) are basic bioorganometallic structures with the potential of combining molecular imaging (99mTc) with therapy (cold Re or 186/188Re). So far, the single carboxylate group on the cyclopentadienyl ring (Cp–) limited targeting to one function. The concept of Cp– as a scaffold for attaching biological molecules could be extended substantially with two or more functionalities bound to the Cp– ligand. Accordingly, the rarely studied bis-substituted cyclopentadienyl ligands [C5H3(1,2-COOMe)2]− and [C5H3(1,3-COOMe)2]− were synthesized and their coordination to the fac-{M(CO)3}+ moiety was studied in water. Both ligands are deprotonated at physiological pH and do not undergo Diels–Alder reactions. In water, they react directly with [Re(OH2)3(CO)3]+ to form [(η5-C5H3{1,2-COOMe}2)Re(CO)3] and [(η5-C5H3{1,3-COOMe}2)Re(CO)3]. Controlled hydrolysis at neutral to alkaline pH gives the monoesters and fully hydrolyzed [(η5-C5H3{1,2-COOH}2)Re(CO)3] and [(η5-C5H3{1,3-COOH}2)Re(CO)3]. Thermal treatment leads to decarboxylation and formation of [(η5-C5H4COOH)Re(CO)3]. The corresponding 99mTc homologues are directly accessible under slightly acidic conditions from [99mTcO4]− in high yields. In the presented strategy, the Cp– ring acts as a scaffold for attaching multiple targeting agents or pharmacophores at the same time